Category Archives: Quantum Physics

Physicists have been trying to unite the discipline's dominant theories of quantum mechanics and general relativity into a grand unifying theory for years and a group of University of British Columbia researchers think they might finally have made some progress towards a solution.

The theories of quantum mechanics and general relativity are the two best ways we have to describe how the universe works.

Quantum mechanics is a branch of physicsthat examines the natural world at the sub-atomic level.

Einstein's theory of general relativity explains phenomena on a grander scale like black holesor how light travels through a galaxy.

While each theory works well to describe phenomena in its respective area, they are mutually incompatible, according to JaymieMatthews, a professor of astronomy and astrophysics at the University of British Columbia..

Even famed Cambridge University mathematics professor Stephen W. Hawking switches between the theories of quantum mechanics and general relativity, Matthews says. (Kimberly White/Reuters)

"General relativity has passed every test that has been put to it. Quantum mechanics as a theory has passed every test that has been applied to it," explained Matthews.

"But if you try to take general relativity to the tiniest scales, it kind of breaks down, and if you take quantum mechanics to the largest scale, it breaks down."

The solution has been to use the theories in their respective areas and kind of avoid the "elephant in the universe" incompatibility issue.

"That profound disagreement between general relativity and quantum mechanics disturbs people."

A new paper by three UBC scientists attempts to reconcile these two theories by addressing the problem of our expanding universe.

Astronomers say theuniverse is constantly expanding at an ever-increasing rate which suggests something, which scientists refer to as dark energy,is pushing it out.

When physicists apply quantum mechanics to this problem, they theorize the energyin questionmust be incredibly dense.

But the theory of relativity says energy with this much density would have a strong gravitational effect which some scientists maintain would cause the universe to explode, which, of course, hasn't happened.

In their paper, UBC PhD students Qingdi Wang and Zhen Zhu, along with physics and astronomy professor Bill Unruh, have devised a formula where they say the value of this forceis fluctuating wildly between positive and negative values and the net result is almost zero.

This accounts for both the zero density and the ever-increasing expansion.

The paper says we can't feel the movement because it is very, very small.

"This happens at very tiny scales, billions and billions times smaller even than an electron," described Wang in a news release.

The research is important because if it is well-received, it could put us closer to a uniform theory of everything.

"If quantum mechanics and general relativity can agree with one another, there is no disturbing cosmological elephant in the universe. That would remove one of the most frustrating things," Matthews said.

Listen to the interview withJaymie Matthews on CBC's The Early Edition:

"We like to think we live in an elegant universe," he added. "This would be one step closer to a grand unified theory in which you could describe the universe on a piece of paper."

The research paper was published in Physical Review D last week.

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UBC researchers propose answer to fundamental space problem - CBC.ca

May 12, 2017 Eduardo Mucciolo, Professor and Chair of the Department of Physics at the University of Central Florida. Credit: University of Central Florida

A well-known computational problem seeks to find the most efficient route for a traveling salesman to visit clients in a number of cities. Seemingly simple, it's actually surprisingly complex and much studied, with implications in fields as wide-ranging as manufacturing and air-traffic control.

Researchers from the University of Central Florida and Boston University have developed a novel approach to solve such difficult computational problems more quickly. As reported May 12 in Nature Communications, they've discovered a way of applying statistical mechanics, a branch of physics, to create more efficient algorithms that can run on traditional computers or a new type of quantum computational machine, said Professor Eduardo Mucciolo, chair of the Department of Physics in UCF's College of Sciences.

Statistical mechanics was developed to study solids, gasses and liquids at macroscopic scales, but is now used to describe a variety of complex states of matter, from magnetism to superconductivity. Methods derived from statistical mechanics have also been applied to understand traffic patterns, the behavior of networks of neurons, sand avalanches and stock market fluctuations.

There already are successful algorithms based on statistical mechanics that are used to solve computational problems. Such algorithms map problems onto a model of binary variables on the nodes of a graph, and the solution is encoded on the configuration of the model with the lowest energy. By building the model into hardware or a computer simulation, researchers can cool the system until it reaches its lowest energy, revealing the solution.

"The problem with this approach is that often one needs to get through phase transitions similar to those found when going from a liquid to a glass phase, where many competing configurations with low energy exist," Mucciolo said. "Such phase transitions slow down the cooling process to a crawl, rendering the method useless."

Mucciolo and fellow physicists Claudio Chamon and Andrei Ruckenstein of BU overcame this hurdle by mapping the original computational problem onto an elegant statistical model without phase transitions, which they called the vertex model. The model is defined on a two-dimensional lattice and each vertex corresponds to a reversible logic gate connected to four neighbors. Input and output data sit at the boundaries of the lattice. The use of reversible logic gates and the regularity of the lattice were crucial ingredients in avoiding the phase-transition snag, Mucciolo said.

"Our method basically runs things in reverse so we can solve these very hard problems," Mucciolo said. "We assign to each of these logic gates an energy. We configured it in such a way that every time these logic gates are satisfied, the energy is very low - therefore, when everything is satisfied, the overall energy of the system should be very low."

Chamon, a professor of physics at BU and the team leader, said the research represents a new way of thinking about the problem.

"This model exhibits no bulk thermodynamic-phase transition, so one of the obstructions for reaching solutions present in previous models was eliminated," he said.

The vertex model may help solve complex problems in machine learning, circuit optimization, and other major computational challenges. The researchers are also exploring whether the model can be applied to the factoring of semi-primes, numbers that are the product of two prime numbers. The difficulty of performing this operation with very large semi-primes underlies modern cryptography and has offered a key rationale for the creation of large-scale quantum computers.

Moreover, the model can be generalized to add another path toward the solution of complex classical computational problems by taking advantage of quantum mechanical parallelismthe fact that, according to quantum mechanics, a system can be in many classical states at the same time.

"Our paper also presents a natural framework for programming special-purpose computational devices, such as D-Wave Systems machines, that use quantum mechanics to speed up the time to solution of classical computational problems," said Ruckenstein.

Zhi-Cheng Yang, a graduate student in physics at BU, is also a co-author on the paper. The universities have applied for a patent on aspects of the vertex model.

Explore further: Study offers new theoretical approach to describing non-equilibrium phase transitions

More information: C. Chamon et al, Quantum vertex model for reversible classical computing, Nature Communications (2017). DOI: 10.1038/ncomms15303

Imaginary numbers are a solution to a very real problem in a study published today in Scientific Reports.

While technologies that currently run on classical computers, such as Watson, can help find patterns and insights buried in vast amounts of existing data, quantum computers will deliver solutions to important problems where ...

One of the most striking discoveries of quantum information theory is the existence of problems that can be solved in a more efficient way with quantum resources than with any known classical algorithm.

How fast will a quantum computer be able to calculate? While fully functional versions of these long-sought technological marvels have yet to be built, one theorist at the National Institute of Standards and Technology (NIST) ...

(Phys.org) -- While there has been some skepticism as to whether the Canadian company D-Waves quantum computing system, the D-Wave One, truly involves quantum computing, the company is intent on proving that the system ...

Physicists have developed a quantum machine learning algorithm that can handle infinite dimensionsthat is, it works with continuous variables (which have an infinite number of possible values on a closed interval) instead ...

A well-known computational problem seeks to find the most efficient route for a traveling salesman to visit clients in a number of cities. Seemingly simple, it's actually surprisingly complex and much studied, with implications ...

By precisely measuring the entropy of a cerium copper gold alloy with baffling electronic properties cooled to nearly absolute zero, physicists in Germany and the United States have gleaned new evidence about the possible ...

When Northwestern Engineering's Erik Luijten met Zbigniew Rozynek, they immediately became united by a mystery.

It's a material world, and an extremely versatile one at that, considering its most basic building blocksatomscan be connected together to form different structures that retain the same composition.

Researchers at the National Institute of Standards and Technology (NIST) have produced and precisely measured a spectrum of X-rays using a new, state-of-the-art machine. The instrument they used to measure the X-rays took ...

Scientists have discovered a way to solve a problem that has baffled humans for so long it is mentioned in the Bible: achieving the most efficient packing of objects such as grains and pharmaceutical drugs.

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If this tech solves the traveling salesman problem in non-polynomial time without quantum computers, the Nobel Committee should create a Computer Science prize for it.

Stimulate-annealing problem was a bitch due to phase transition. This seems like actually innovation, rather than the descriptive and iceberg-meting garbage permeating the site.

Really cool work, love to see physicists in CS. Simulated Annealling is the beginning, I think there's a lot more: a principle of least information in AI will emerge, I predict, matching physics principle of least action, and in time computation will illuminate more physics. For instance, imagine if its NOT the case that there is physical solution to Travelling salesman or other NP complete problems, (meaning no physical system computes their solution) that's profound as a solution. It implies an anonymity to photons for instance, the fact that they have no history. It also lends a lot of credence to those weird ideas that we're all living in a computer simulation.

Einsteins quote about everything being explained as simply as possible is sort of similar - less energy expenditure.

Right, Occam's razor has formal statements in information theory too. Its really just kind of common sense: if we encoded the world around us smartly, common things, like an orange in an orange tree, would little information to encode, but uncommon things, like a traffic cone in an orange tree would take more info. So an AI, on seeing something orange between the leaves of an orange tree, should assume its an orange, as our brains would.

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Physics may bring faster solutions for tough computational problems - Phys.Org

In physics, a quantum (plural: quanta) is the minimum amount of any physical entity involved in an interaction. The fundamental notion that a physical property may be "quantized" is referred to as "the hypothesis of quantization".[1] This means that the magnitude of the physical property can take on only certain discrete values.

For example, a photon is a single quantum of light (or of any other form of electromagnetic radiation), and can be referred to as a "light quantum". Similarly, the energy of an electron bound within an atom is also quantized, and thus can only exist in certain discrete values. The fact that electrons can only exist at discrete energy levels in an atom causes atoms to be stable, and hence matter in general is stable.

Quantization is one of the foundations of the much broader physics of quantum mechanics. Quantization of the energy and its influence on how energy and matter interact (quantum electrodynamics) is part of the fundamental framework for understanding and describing nature.

The word quantum comes from the Latin quantus, meaning "how great". "Quanta", short for "quanta of electricity" (electrons), was used in a 1902 article on the photoelectric effect by Philipp Lenard, who credited Hermann von Helmholtz for using the word in the area of electricity. However, the word quantum in general was well known before 1900.[2] It was often used by physicians, such as in the term quantum satis. Both Helmholtz and Julius von Mayer were physicians as well as physicists. Helmholtz used quantum with reference to heat in his article[3] on Mayer's work, and the word quantum can be found in the formulation of the first law of thermodynamics by Mayer in his letter[4] dated July 24, 1841. Max Planck used quanta to mean "quanta of matter and electricity",[5] gas, and heat.[6] In 1905, in response to Planck's work and the experimental work of Lenard (who explained his results by using the term quanta of electricity), Albert Einstein suggested that radiation existed in spatially localized packets which he called "quanta of light" ("Lichtquanta").[7]

The concept of quantization of radiation was discovered in 1900 by Max Planck, who had been trying to understand the emission of radiation from heated objects, known as black-body radiation. By assuming that energy can only be absorbed or released in tiny, differential, discrete packets he called "bundles" or "energy elements",[8] Planck accounted for certain objects changing colour when heated.[9] On December 14, 1900, Planck reported his findings to the German Physical Society, and introduced the idea of quantization for the first time as a part of his research on black-body radiation.[10] As a result of his experiments, Planck deduced the numerical value of h, known as the Planck constant, and could also report a more precise value for the AvogadroLoschmidt number, the number of real molecules in a mole and the unit of electrical charge, to the German Physical Society. After his theory was validated, Planck was awarded the Nobel Prize in Physics in 1918 for his discovery.

While quantization was first discovered in electromagnetic radiation, it describes a fundamental aspect of energy not just restricted to photons.[11] In the attempt to bring experiment into agreement with theory, Max Planck postulated that electromagnetic energy is absorbed or emitted in discrete packets, or quanta.[12]

The adjective "quantum" is frequently used in common parlance to mean the opposite of its scientific definition. A "quantum leap" has been used colloquially since the 1950s to imply a large change, as opposed to the smallest possible change.[13][14] It is also used in a range of pseudoscientific beliefs (quantum mysticism), where the adjective is used to imply that a paranormal event is a consequence of quantum physics.[15][16]

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Quantum - Wikipedia

May 10, 2017 The rotating centrifuge in which the entangled photon source was accelerated to 30 times its weight. Credit: IQOQI/AW

Einstein's "spooky action at a distance" persists even at high accelerations, researchers of the Austrian Academy of Sciences and the University of Vienna were able to show in a new experiment. A source of entangled photon pairs was exposed to massive stress: The photons' entanglement survived the drop in a fall tower as well as 30 times the Earth's gravitational acceleration in a centrifuge. This was reported in the most recent issue of Nature Communications. The experiment helps deepen our understanding of quantum mechanics and at the same time gives valuable results for quantum experiments in space.

Einstein's theory of relativity and the theory of quantum mechanics are two important pillars of modern physics. On the way of achieving a "Theory of Everything," these two theories have to be unified. This has not been achieved as of today, since phenomena of both theories can hardly be observed simultaneously. A typical example of a quantum mechanical phenomenon is entanglement: This means that the measurement of one of a pair of light particles, so-called photons, defines the state of the other particle immediately, regardless of their separation. High accelerations on the other hand can best be described by the theory of relativity. Now for the first time, quantum technologies enable us to observe these phenomena at once: The stability of quantum mechanical entanglement of photon pairs can be tested while the photons undergo relativistically relevant acceleration.

Quantum entanglement proves to be highly robust

Researchers of the Viennese Institute of Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences (OeAW) and of the University of Vienna have now investigated this area of research experimentally for the first time. They could show in their experiment that entanglement between photons survives even when the source of entangled photon pairs including the detectors are experiencing free fall or are being accelerated with 30g, that is, 30 times the Earth's acceleration. Doing so, the Viennese researchers have experimentally established an upper bound below which there is no degradation of entanglement quality.

Important for quantum experiments with satellites

"These experiments shall help to unify the theories of quantum mechanics and relativity," says Rupert Ursin, group leader at IQOQI Vienna. The sturdiness of quantum entanglement even for strongly accelerated systems is crucial also for quantum experiments in space. "If entanglement were too fragile, quantum experiments could not be carried out on a satellite or an accelerated spacecraft or only in a very limited range," exemplifies Matthias Fink, first author of the publication.

12 meters falling height and 30g

In order to prove the robustness of quantum entanglement, quantum physicist Matthias Fink and his colleagues mounted a source of polarization-entangled photon pairs in a crate which was firstly dropped from a height of 12 meters to achieve zero gravity during the fall. In the second part of the experiment, the crate was fixed to the arm of a centrifuge and then accelerated up to 30g. As a comparison for the reader: A roller coaster ride exerts maximally 6g on the passengers.

Detectors mounted on the crate monitored the photons' entanglement during the experiments. Analysing the data, the physicists could calculate an upper bound of disadvantageous effects of acceleration on entanglement. The data showed that entanglement quality did not significantly exceed the expected contribution of background noise. "Our next challenge will be to stabilize the setup even more in order for it to withstand much higher accelerations. This would enhance the explanatory power of the experiment even further," says Matthias Fink.

Explore further: Researchers demonstrated violation of Bell's inequality on frequency-bin entangled photon pairs

More information: Experimental test of photonic entanglement in accelerated reference frames, Nature Communications, 2017. DOI: 10.1038/NCOMMS15304

Quantum entanglement, one of the most intriguing features of multi-particle quantum systems, has become a fundamental building block in both quantum information processing and quantum computation. If two particles are entangled, ...

Scientists have discovered a new mechanism involved in the creation of paired light particles, which could have significant impact on the study of quantum physics.

Researchers at the Institute of Quantum Optics and Quantum Information, the University of Vienna, and the Universitat Autonoma de Barcelona have achieved a new milestone in quantum physics: they were able to entangle three ...

Albert Einstein called quantum entanglementtwo particles in different locations, even on other sides of the universe, influencing each other"spooky action at a distance."

Physicists of the group of Prof. Anton Zeilinger at the Institute for Quantum Optics and Quantum Information (IQOQI), the University of Vienna, and the Vienna Center for Quantum Science and Technology (VCQ) have, for the ...

(Phys.org)"Spooky action at a distance," Einstein's famous, dismissive characterization of quantum entanglement, has long been established as a physical phenomenon, and researchers are keen to develop practical applications ...

Researchers have uncovered the exact mechanism that causes new solar cells to break down in air, paving the way for a solution.

More than 400 years ago, renowned mathematician and scientist Johannes Kepler speculated about the creation of one of nature's most angelic and unique shapes: the six-sided snowflake. Although atoms would not be discovered ...

(Phys.org)Physicists have theoretically shown that a superconducting current of electrons can be induced to flow by a new kind of transport mechanism: the potential flow of information. This unusual phenomenon is predicted ...

National Institute of Standards and Technology (NIST) physicists have solved the seemingly intractablepuzzle of how to control the quantum properties of individual charged molecules, or molecular ions. Thesolution is to use ...

Einstein's "spooky action at a distance" persists even at high accelerations, researchers of the Austrian Academy of Sciences and the University of Vienna were able to show in a new experiment. A source of entangled photon ...

An experiment at the cutting edge of condensed matter physics and materials science has revealed that the dream of more efficient energy usage can become reality. An international collaboration led by the scientists of Italy's ...

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It's way past time for sci-writers to stop gushing, "Spooky action, blah, blah". No one not living on Mars is not sick of this tired put-down of entanglement, not unlike the despised `god particle' moniker of the Higgs. AE did not believe in god or spooks, & used those terms colloquially. But now the sci-writers, lacking any creativity for modern descriptions, all parrot AE.

What? Is this supposed to mean the centrifuge produced 30g?

The use of intriguing and interesting language to inspire interest in the subject at hand is a tool used by all journalists. Spooky action at a distance has been referred to as often as it has because it is effective at gaining attention. To lobby for the removal of such an iconic phrase as spooky action at a distance from scientific journals would be counterproductive to the goal of spreading interest in the scientific study of reality and the laws governing it. There is an intrinsic value to use outrageous language to describe outrageous scientific phenomenon. One of Einstein's greatest contributions to science was the interest he created in the subject. Also while his religious beliefs were far from firmly established he often referred to a Force having a role in the guiding of our universe. The article was informative, interesting, and entertaining. And just to make clear what was very clear in the article, yes 30 times Earth's gravity is 30g. It said 30g multiple times

The force does not guide. It survives. Whether anyone learns... we'll see.

Fill a bucket on a rope with water, whirl it around, figure out why the water doesn't spill. Or read this 🙂 https://en.wikipe...ntrifuge

What was discovered was that the aperatus could survive. The limited "relative forces" of these experiments really can't be expected to do much else. Want to determin the "strength" of entangment then send one of the entangled pairs through an accelerator.

Hence you have here peddling cliches, catch phrases, gross simplifications in the aura of mystery and discovery while scientific formalism suffers. All in attempt to draw audiences to science and advertisers.

This particular piece fails to explain what actually those researchers wanted to accomplish and why would they expect entanglement of photons (a phase entanglement vs. spin (magnetic) entanglement) to be affected by inertial acceleration of measly 30g (1E5g may be).

Also and most importantly why would they expect to influence an "undetermined" state of a phase of light of entangled pair by mechanical force. I am sure in the paper they answer those questions quite simply.

An interesting take on addressing the problem of misinterpretation of QM I found here: https://questforn...-quanta/

It's an important point that entanglement still occurs across varying gravity strengths. It's one of those assumptions that must be tested; these are some important negative results.

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Unbreakable quantum entanglement - Phys.Org

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FORT WORTH (CBS11) He studies the theories behind the subatomic building blocks of the universe. Hes earned a degree in physics from TCU. He is 14-years old.

Most 14-year-olds are learning to navigate the halls of high school as a freshman.

Carson Huey-You navigates the intricate world of quantum physics on a wall-sized college classroom white board.

Im studying physics but in particular quantum physics eventually going into research and teaching after graduate school, he said.

Huey-You will graduate TCU with a bachelors degree in physics Saturday.

He was 10 when Professor Magnus Rittby took him under his wing.

Of course I had reservations, he laughed. Ive never seen a 10-year-old apply for college. But he was a bright kid and I just thought it was worth fighting for him to get admitted and try it.

The age difference between him and his classmates is something Huey-You is accustomed to. After homeschooling, he started school in the 8th grade at five years old.

Its no different than what Im used to because I was around it all through high school, Huey-You said. So, I got used to it there and its really the same thing here. Its also good because they sort of accept me as an equal.

And that acceptance came with more than classwork as a 10-year-old had to learn how to manage himself maturely in a college environment.

I tried making it work both ways, Rittby said. That is, being mature about the academics but still being able to be a kid at heart which I think he still is. And I want to keep it that way.

I have Cannan my younger brother, Huey-You said of how he spends his down time. So we play together a lot. I have a puppy named Klaus. He likes to run around and hes very energetic.

Perhaps its not surprising that in a world of theoretical formulas where age is not a factor Huey-You never thought that he could actually earn his PhD when other students his age are graduating high school.

Its kind of surprising but then at the same time its really cool! he laughed.

His younger brother Cannan is graduating high school this week and will study physics and astronomy at TCU.

He is 11 years-old and already has taken some advanced classes at TCU.

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14-Year-Old Earns Physics Degree From TCU CBS Dallas / Fort ... - CBS DFW

Quantum entanglement is just one of the many weird things that pop up when you try to understand the laws governing the world of subatomic particles. The phenomenon of entanglement wherein two particles can be separated by billions of light-years and yet be instantly affected by changes to the quantum state of one another seems so outlandish that even Albert Einstein (the essence of intelligence anthropomorphized) had trouble wrapping his head around the concept.

Despite Einsteins reservations, though, quantum entanglement has been empirically observed several times over the past few decades. The spooky action at a distance as the famed physicist once derisively called it is very real.

Read:Schrdingers Cat Is Now Dead And Alive In Two Boxes

In a series of experiments described in a study published Wednesday in the journal Nature Communications a team of researchers has now shown that quantum entanglement persists even at high accelerations. The experiments not only help scientists deepen their understanding of quantum mechanics, they also help them take a step toward the holy grail of particle physics the unification of quantum mechanics and relativity.

In their experiments, the researchers subjected pairs of entangled photons to accelerations of up to 30g (or 30 times the acceleration due to gravity a free-falling object experiences on Earth) in centrifuges.

Detectors mounted on the crate monitored the photons' entanglement during the experiments. Analysing the data, the physicists could calculate an upper bound of disadvantageous effects of acceleration on entanglement, the University of Vienna explained in a statement. The data showed thatentanglement quality did not significantly exceed the expected contribution of background noise.

Not only do the experiments prove that the phenomenon of entanglement is strong enough to persist even in experiments that may one day be carried out on a satellite or an accelerated spacecraft, they also suggests quantum mechanical entanglement ofphoton pairscan be tested while the particles undergo relativistic acceleration conditions under whichattempts to unify quantum mechanics and relativity into an overarching theory of everything can be made.

Currently, the universe we live in obeys two seemingly incompatiblelaws quantum mechanics, whichgovernsthe behavior of subatomic particles;and relativity, which describeshow clumps of atoms, such ashumans, stars and galaxies,behave. Formulating an all-encompassing theory of everything, one that resolves the apparent contradictions between quantum mechanics and relativity has, for the longest time, been the main goal of particle physicists.

This, however, is easier said than done. The seemingly insurmountable problem is that gravity, which is a product of massive objects warping space-time as explained by Einsteins theory of general relativity does not follow the laws of quantum physics.

As long as these descriptions of nature remain confined to their own scope of application, they cannot contribute to a unified theory that captures physics at the boundary between these specialized regimes, the researchers wrote in the study. Our experimental platform represents a testbed that can readily be upgraded for measurements with higher precision, by using a ultra-bright source of entangled photons, and higher-dimensional degrees of freedom, such as energy-time entanglement.

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Quantum Entanglement Persists Even Under High Accelerations ... - International Business Times

Quantum entanglement is just one of the many weird things that pop up when you try to understand the laws governing the world of subatomic particles. The phenomenon of entanglement wherein two particles can be separated by billions of light-years and yet be instantly affected by changes to the quantum state of one another seems so outlandish that even Albert Einstein (the essence of intelligence anthropomorphized) had trouble wrapping his head around the concept.

Despite Einsteins reservations, though, quantum entanglement has been empirically observed several times over the past few decades. The spooky action at a distance as the famed physicist once derisively called it is very real.

Read:Schrdingers Cat Is Now Dead And Alive In Two Boxes

In a series of experiments described in a study published Wednesday in the journal Nature Communications a team of researchers has now shown that quantum entanglement persists even at high accelerations. The experiments not only help scientists deepen their understanding of quantum mechanics, they also help them take a step toward the holy grail of particle physics the unification of quantum mechanics and relativity.

In their experiments, the researchers subjected pairs of entangled photons to accelerations of up to 30g (or 30 times the acceleration due to gravity a free-falling object experiences on Earth) in centrifuges.

Detectors mounted on the crate monitored the photons' entanglement during the experiments. Analysing the data, the physicists could calculate an upper bound of disadvantageous effects of acceleration on entanglement, the University of Vienna explained in a statement. The data showed thatentanglement quality did not significantly exceed the expected contribution of background noise.

Not only do the experiments prove that the phenomenon of entanglement is strong enough to persist even in experiments that may one day be carried out on a satellite or an accelerated spacecraft, they also suggests quantum mechanical entanglement ofphoton pairscan be tested while the particles undergo relativistic acceleration conditions under whichattempts to unify quantum mechanics and relativity into an overarching theory of everything can be made.

Currently, the universe we live in obeys two seemingly incompatiblelaws quantum mechanics, whichgovernsthe behavior of subatomic particles;and relativity, which describeshow clumps of atoms, such ashumans, stars and galaxies,behave. Formulating an all-encompassing theory of everything, one that resolves the apparent contradictions between quantum mechanics and relativity has, for the longest time, been the main goal of particle physicists.

This, however, is easier said than done. The seemingly insurmountable problem is that gravity, which is a product of massive objects warping space-time as explained by Einsteins theory of general relativity does not follow the laws of quantum physics.

As long as these descriptions of nature remain confined to their own scope of application, they cannot contribute to a unified theory that captures physics at the boundary between these specialized regimes, the researchers wrote in the study. Our experimental platform represents a testbed that can readily be upgraded for measurements with higher precision, by using a ultra-bright source of entangled photons, and higher-dimensional degrees of freedom, such as energy-time entanglement.

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Quantum Entanglement Persists Even Under High Accelerations, Experiments Reveal - International Business Times

We are living through the most heavily freighted general election of modern times, with several weighty and overlapping questions bearing down upon it.

It will, of course, be remembered as the Euro election for the party competition about the nature of Brexit and the future relations of Britain with the European Union, all of which morphs into the wider Britains-place-in-the-world question.

The very configuration and make-up of the United Kingdom is also in play, with the Scottish question running through the pursuit of seats north of the border, even though the last referendum on independence is but two-and-a-half years behind us. By the time of the 2022 general, election we could be a much diminished nation, out of the European Union and shorn of Scotland.

In that event, a political nation consisting of England, Wales and Northern Ireland would be hard put to provide a plausible centre-Left alternative government, or to place a programme before the electorate, even if Labour could somehow emerge healed and growing in strength out of its current period of intense self-harm. For the survival of the standard model of UK politics is also in play in the 2017 general election it is a model that does not fly without the jostling between liberal capitalism and social democracy that, so far, has been the essential nature of all our general elections since 1945.

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A general election, like quantum physics, is a thing of waves and particles - The Tablet

This article is a non-technical introduction to the subject. For the main encyclopedia article, see Quantum mechanics.

Quantum mechanics is the science of the very small. It explains the behaviour of matter and its interactions with energy on the scale of atoms and subatomic particles.

By contrast, classical physics only explains matter and energy on a scale familiar to human experience, including the behaviour of astronomical bodies such as the Moon. Classical physics is still used in much of modern science and technology. However, towards the end of the 19th century, scientists discovered phenomena in both the large (macro) and the small (micro) worlds that classical physics could not explain.[1] Coming to terms with these limitations led to two major revolutions in physics which created a shift in the original scientific paradigm: the theory of relativity and the development of quantum mechanics.[2] This article describes how physicists discovered the limitations of classical physics and developed the main concepts of the quantum theory that replaced it in the early decades of the 20th century. These concepts are described in roughly the order in which they were first discovered. For a more complete history of the subject, see History of quantum mechanics.

Light behaves in some respects like particles and in other respects like waves. Matterparticles such as electrons and atomsexhibits wavelike behaviour too. Some light sources, including neon lights, give off only certain frequencies of light. Quantum mechanics shows that light, along with all other forms of electromagnetic radiation, comes in discrete units, called photons, and predicts its energies, colours, and spectral intensities. Since one never observes half a photon, a single photon is a quantum, or smallest observable amount, of the electromagnetic field. More broadly, quantum mechanics shows that many quantities, such as angular momentum, that appeared to be continuous in the zoomed-out view of classical mechanics, turn out to be (at the small, zoomed-in scale of quantum mechanics) quantized. Angular momentum is required to take on one of a set of discrete allowable values, and since the gap between these values is so minute, the discontinuity is only apparent at the atomic level.

Many aspects of quantum mechanics are counterintuitive and can seem paradoxical, because they describe behaviour quite different from that seen at larger length scales. In the words of quantum physicist Richard Feynman, quantum mechanics deals with "nature as She is absurd".[3] For example, the uncertainty principle of quantum mechanics means that the more closely one pins down one measurement (such as the position of a particle), the less accurate another measurement pertaining to the same particle (such as its momentum) must become.

Thermal radiation is electromagnetic radiation emitted from the surface of an object due to the object's internal energy. If an object is heated sufficiently, it starts to emit light at the red end of the spectrum, as it becomes red hot.

Heating it further causes the colour to change from red to yellow, white, and blue, as light at shorter wavelengths (higher frequencies) begins to be emitted. A perfect emitter is also a perfect absorber: when it is cold, such an object looks perfectly black, because it absorbs all the light that falls on it and emits none. Consequently, an ideal thermal emitter is known as a black body, and the radiation it emits is called black-body radiation.

In the late 19th century, thermal radiation had been fairly well characterized experimentally.[note 1] However, classical physics led to the Rayleigh-Jeans law, which, as shown in the figure, agrees with experimental results well at low frequencies, but strongly disagrees at high frequencies. Physicists searched for a single theory that explained all the experimental results.

The first model that was able to explain the full spectrum of thermal radiation was put forward by Max Planck in 1900.[4] He proposed a mathematical model in which the thermal radiation was in equilibrium with a set of harmonic oscillators. To reproduce the experimental results, he had to assume that each oscillator emitted an integer number of units of energy at its single characteristic frequency, rather than being able to emit any arbitrary amount of energy. In other words, the energy emitted by an oscillator was quantized.[note 2] The quantum of energy for each oscillator, according to Planck, was proportional to the frequency of the oscillator; the constant of proportionality is now known as the Planck constant. The Planck constant, usually written as h, has the value of 69666629999999999996.631034J s. So, the energy E of an oscillator of frequency f is given by

To change the colour of such a radiating body, it is necessary to change its temperature. Planck's law explains why: increasing the temperature of a body allows it to emit more energy overall, and means that a larger proportion of the energy is towards the violet end of the spectrum.

Planck's law was the first quantum theory in physics, and Planck won the Nobel Prize in 1918 "in recognition of the services he rendered to the advancement of Physics by his discovery of energy quanta".[6] At the time, however, Planck's view was that quantization was purely a heuristic mathematical construct, rather than (as is now believed) a fundamental change in our understanding of the world.[7]

In 1905, Albert Einstein took an extra step. He suggested that quantisation was not just a mathematical construct, but that the energy in a beam of light actually occurs in individual packets, which are now called photons.[8]The energy of a single photon is given by its frequency multiplied by Planck's constant:

For centuries, scientists had debated between two possible theories of light: was it a wave or did it instead comprise a stream of tiny particles? By the 19th century, the debate was generally considered to have been settled in favour of the wave theory, as it was able to explain observed effects such as refraction, diffraction, interference and polarization. James Clerk Maxwell had shown that electricity, magnetism and light are all manifestations of the same phenomenon: the electromagnetic field. Maxwell's equations, which are the complete set of laws of classical electromagnetism, describe light as waves: a combination of oscillating electric and magnetic fields. Because of the preponderance of evidence in favour of the wave theory, Einstein's ideas were met initially with great skepticism. Eventually, however, the photon model became favoured. One of the most significant pieces of evidence in its favour was its ability to explain several puzzling properties of the photoelectric effect, described in the following section. Nonetheless, the wave analogy remained indispensable for helping to understand other characteristics of light: diffraction, refraction and interference.

In 1887, Heinrich Hertz observed that when light with sufficient frequency hits a metallic surface, it emits electrons.[9] In 1902, Philipp Lenard discovered that the maximum possible energy of an ejected electron is related to the frequency of the light, not to its intensity: if the frequency is too low, no electrons are ejected regardless of the intensity. Strong beams of light toward the red end of the spectrum might produce no electrical potential at all, while weak beams of light toward the violet end of the spectrum would produce higher and higher voltages. The lowest frequency of light that can cause electrons to be emitted, called the threshold frequency, is different for different metals. This observation is at odds with classical electromagnetism, which predicts that the electron's energy should be proportional to the intensity of the radiation.[10]:24 So when physicists first discovered devices exhibiting the photoelectric effect, they initially expected that a higher intensity of light would produce a higher voltage from the photoelectric device.

Einstein explained the effect by postulating that a beam of light is a stream of particles ("photons") and that, if the beam is of frequency f, then each photon has an energy equal to hf.[9] An electron is likely to be struck only by a single photon, which imparts at most an energy hf to the electron.[9] Therefore, the intensity of the beam has no effect[note 3] and only its frequency determines the maximum energy that can be imparted to the electron.[9]

To explain the threshold effect, Einstein argued that it takes a certain amount of energy, called the work function and denoted by , to remove an electron from the metal.[9] This amount of energy is different for each metal. If the energy of the photon is less than the work function, then it does not carry sufficient energy to remove the electron from the metal. The threshold frequency, f0, is the frequency of a photon whose energy is equal to the work function:

If f is greater than f0, the energy hf is enough to remove an electron. The ejected electron has a kinetic energy, EK, which is, at most, equal to the photon's energy minus the energy needed to dislodge the electron from the metal:

Einstein's description of light as being composed of particles extended Planck's notion of quantised energy, which is that a single photon of a given frequency, f, delivers an invariant amount of energy, hf. In other words, individual photons can deliver more or less energy, but only depending on their frequencies. In nature, single photons are rarely encountered. The Sun and emission sources available in the 19th century emit vast numbers of photons every second, and so the importance of the energy carried by each individual photon was not obvious. Einstein's idea that the energy contained in individual units of light depends on their frequency made it possible to explain experimental results that had hitherto seemed quite counterintuitive. However, although the photon is a particle, it was still being described as having the wave-like property of frequency. Once again, the particle account of light was being compromised[11][note 4].

The relationship between the frequency of electromagnetic radiation and the energy of each individual photon is why ultraviolet light can cause sunburn, but visible or infrared light cannot. A photon of ultraviolet light will deliver a high amount of energy enough to contribute to cellular damage such as occurs in a sunburn. A photon of infrared light will deliver a lower amount of energy only enough to warm one's skin. So, an infrared lamp can warm a large surface, perhaps large enough to keep people comfortable in a cold room, but it cannot give anyone a sunburn.

All photons of the same frequency have identical energy, and all photons of different frequencies have proportionally (order 1, Ephoton = hf ) different energies. However, although the energy imparted by photons is invariant at any given frequency, the initial energy state of the electrons in a photoelectric device prior to absorption of light is not necessarily uniform. Anomalous results may occur in the case of individual electrons. For instance, an electron that was already excited above the equilibrium level of the photoelectric device might be ejected when it absorbed uncharacteristically low frequency illumination. Statistically, however, the characteristic behaviour of a photoelectric device will reflect the behaviour of the vast majority of its electrons, which will be at their equilibrium level. This point is helpful in comprehending the distinction between the study of individual particles in quantum dynamics and the study of massed particles in classical physics.

By the dawn of the 20th century, evidence required a model of the atom with a diffuse cloud of negatively charged electrons surrounding a small, dense, positively charged nucleus. These properties suggested a model in which the electrons circle around the nucleus like planets orbiting a sun.[note 5] However, it was also known that the atom in this model would be unstable: according to classical theory, orbiting electrons are undergoing centripetal acceleration, and should therefore give off electromagnetic radiation, the loss of energy also causing them to spiral toward the nucleus, colliding with it in a fraction of a second.

A second, related, puzzle was the emission spectrum of atoms. When a gas is heated, it gives off light only at discrete frequencies. For example, the visible light given off by hydrogen consists of four different colours, as shown in the picture below. The intensity of the light at different frequencies is also different. By contrast, white light consists of a continuous emission across the whole range of visible frequencies. By the end of the nineteenth century, a simple rule known as Balmer's formula had been found which showed how the frequencies of the different lines were related to each other, though without explaining why this was, or making any prediction about the intensities. The formula also predicted some additional spectral lines in ultraviolet and infrared light which had not been observed at the time. These lines were later observed experimentally, raising confidence in the value of the formula.

The mathematical formula describing hydrogen's emission spectrum.

In 1885 the Swiss mathematician Johann Balmer discovered that each wavelength (lambda) in the visible spectrum of hydrogen is related to some integer n by the equation

where B is a constant which Balmer determined to be equal to 364.56nm.

In 1888 Johannes Rydberg generalized and greatly increased the explanatory utility of Balmer's formula. He predicted that is related to two integers n and m according to what is now known as the Rydberg formula:[13]

where R is the Rydberg constant, equal to 0.0110nm1, and n must be greater than m.

Rydberg's formula accounts for the four visible wavelengths of hydrogen by setting m = 2 and n = 3, 4, 5, 6. It also predicts additional wavelengths in the emission spectrum: for m = 1 and for n > 1, the emission spectrum should contain certain ultraviolet wavelengths, and for m = 3 and n > 3, it should also contain certain infrared wavelengths. Experimental observation of these wavelengths came two decades later: in 1908 Louis Paschen found some of the predicted infrared wavelengths, and in 1914 Theodore Lyman found some of the predicted ultraviolet wavelengths.[13]

Note that both Balmer and Rydberg's formulas involve integers: in modern terms, they imply that some property of the atom is quantised. Understanding exactly what this property was, and why it was quantised, was a major part in the development of quantum mechanics, as will be shown in the rest of this article.

In 1913 Niels Bohr proposed a new model of the atom that included quantized electron orbits: electrons still orbit the nucleus much as planets orbit around the sun, but they are only permitted to inhabit certain orbits, not to orbit at any distance.[14] When an atom emitted (or absorbed) energy, the electron did not move in a continuous trajectory from one orbit around the nucleus to another, as might be expected classically. Instead, the electron would jump instantaneously from one orbit to another, giving off the emitted light in the form of a photon.[15] The possible energies of photons given off by each element were determined by the differences in energy between the orbits, and so the emission spectrum for each element would contain a number of lines.[16]

Starting from only one simple assumption about the rule that the orbits must obey, the Bohr model was able to relate the observed spectral lines in the emission spectrum of hydrogen to previously known constants. In Bohr's model the electron simply wasn't allowed to emit energy continuously and crash into the nucleus: once it was in the closest permitted orbit, it was stable forever. Bohr's model didn't explain why the orbits should be quantised in that way, nor was it able to make accurate predictions for atoms with more than one electron, or to explain why some spectral lines are brighter than others.

Although some of the fundamental assumptions of the Bohr model were soon found to be wrong, the key result that the discrete lines in emission spectra are due to some property of the electrons in atoms being quantised is correct. The way that the electrons actually behave is strikingly different from Bohr's atom, and from what we see in the world of our everyday experience; this modern quantum mechanical model of the atom is discussed below.

A more detailed explanation of the Bohr model.

Bohr theorised that the angular momentum, L, of an electron is quantised:

where n is an integer and h is the Planck constant. Starting from this assumption, Coulomb's law and the equations of circular motion show that an electron with n units of angular momentum will orbit a proton at a distance r given by

where ke is the Coulomb constant, m is the mass of an electron, and e is the charge on an electron. For simplicity this is written as

where a0, called the Bohr radius, is equal to 0.0529nm. The Bohr radius is the radius of the smallest allowed orbit.

The energy of the electron[note 6] can also be calculated, and is given by

Thus Bohr's assumption that angular momentum is quantised means that an electron can only inhabit certain orbits around the nucleus, and that it can have only certain energies. A consequence of these constraints is that the electron will not crash into the nucleus: it cannot continuously emit energy, and it cannot come closer to the nucleus than a0 (the Bohr radius).

An electron loses energy by jumping instantaneously from its original orbit to a lower orbit; the extra energy is emitted in the form of a photon. Conversely, an electron that absorbs a photon gains energy, hence it jumps to an orbit that is farther from the nucleus.

Each photon from glowing atomic hydrogen is due to an electron moving from a higher orbit, with radius rn, to a lower orbit, rm. The energy E of this photon is the difference in the energies En and Em of the electron:

Since Planck's equation shows that the photon's energy is related to its wavelength by E = hc/, the wavelengths of light that can be emitted are given by

This equation has the same form as the Rydberg formula, and predicts that the constant R should be given by

Therefore, the Bohr model of the atom can predict the emission spectrum of hydrogen in terms of fundamental constants.[note 7] However, it was not able to make accurate predictions for multi-electron atoms, or to explain why some spectral lines are brighter than others.

Just as light has both wave-like and particle-like properties, matter also has wave-like properties.[17]

Matter behaving as a wave was first demonstrated experimentally for electrons: a beam of electrons can exhibit diffraction, just like a beam of light or a water wave.[note 8] Similar wave-like phenomena were later shown for atoms and even molecules.

The wavelength, , associated with any object is related to its momentum, p, through the Planck constant, h:[18][19]

The relationship, called the de Broglie hypothesis, holds for all types of matter: all matter exhibits properties of both particles and waves.

The concept of waveparticle duality says that neither the classical concept of "particle" nor of "wave" can fully describe the behaviour of quantum-scale objects, either photons or matter. Waveparticle duality is an example of the principle of complementarity in quantum physics.[20][21][22][23][24] An elegant example of waveparticle duality, the double slit experiment, is discussed in the section below.

In the double-slit experiment, as originally performed by Thomas Young and Augustin Fresnel in 1827, a beam of light is directed through two narrow, closely spaced slits, producing an interference pattern of light and dark bands on a screen. If one of the slits is covered up, one might naively expect that the intensity of the fringes due to interference would be halved everywhere. In fact, a much simpler pattern is seen, a simple diffraction pattern. Closing one slit results in a much simpler pattern diametrically opposite the open slit. Exactly the same behaviour can be demonstrated in water waves, and so the double-slit experiment was seen as a demonstration of the wave nature of light.

Variations of the double-slit experiment have been performed using electrons, atoms, and even large molecules,[25][26] and the same type of interference pattern is seen. Thus it has been demonstrated that all matter possesses both particle and wave characteristics.

Even if the source intensity is turned down, so that only one particle (e.g. photon or electron) is passing through the apparatus at a time, the same interference pattern develops over time. The quantum particle acts as a wave when passing through the double slits, but as a particle when it is detected. This is a typical feature of quantum complementarity: a quantum particle will act as a wave in an experiment to measure its wave-like properties, and like a particle in an experiment to measure its particle-like properties. The point on the detector screen where any individual particle shows up will be the result of a random process. However, the distribution pattern of many individual particles will mimic the diffraction pattern produced by waves.

De Broglie expanded the Bohr model of the atom by showing that an electron in orbit around a nucleus could be thought of as having wave-like properties. In particular, an electron will be observed only in situations that permit a standing wave around a nucleus. An example of a standing wave is a violin string, which is fixed at both ends and can be made to vibrate. The waves created by a stringed instrument appear to oscillate in place, moving from crest to trough in an up-and-down motion. The wavelength of a standing wave is related to the length of the vibrating object and the boundary conditions. For example, because the violin string is fixed at both ends, it can carry standing waves of wavelengths 2l/n, where l is the length and n is a positive integer. De Broglie suggested that the allowed electron orbits were those for which the circumference of the orbit would be an integer number of wavelengths. The electron's wavelength therefore determines that only Bohr orbits of certain distances from the nucleus are possible. In turn, at any distance from the nucleus smaller than a certain value it would be impossible to establish an orbit. The minimum possible distance from the nucleus is called the Bohr radius.[27]

De Broglie's treatment of quantum events served as a starting point for Schrdinger when he set out to construct a wave equation to describe quantum theoretical events.

In 1922, Otto Stern and Walther Gerlach shot silver atoms through an (inhomogeneous) magnetic field. In classical mechanics, a magnet thrown through a magnetic field may be, depending on its orientation (if it is pointing with its northern pole upwards or down, or somewhere in between), deflected a small or large distance upwards or downwards. The atoms that Stern and Gerlach shot through the magnetic field acted in a similar way. However, while the magnets could be deflected variable distances, the atoms would always be deflected a constant distance either up or down. This implied that the property of the atom which corresponds to the magnet's orientation must be quantised, taking one of two values (either up or down), as opposed to being chosen freely from any angle.

Ralph Kronig originated the theory that particles such as atoms or electrons behave as if they rotate, or "spin", about an axis. Spin would account for the missing magnetic moment[clarification needed], and allow two electrons in the same orbital to occupy distinct quantum states if they "spun" in opposite directions, thus satisfying the exclusion principle. The quantum number represented the sense (positive or negative) of spin.

The choice of orientation of the magnetic field used in the Stern-Gerlach experiment is arbitrary. In the animation shown here, the field is vertical and so the atoms are deflected either up or down. If the magnet is rotated a quarter turn, the atoms will be deflected either left or right. Using a vertical field shows that the spin along the vertical axis is quantised, and using a horizontal field shows that the spin along the horizontal axis is quantised.

If, instead of hitting a detector screen, one of the beams of atoms coming out of the Stern-Gerlach apparatus is passed into another (inhomogeneous) magnetic field oriented in the same direction, all of the atoms will be deflected the same way in this second field. However, if the second field is oriented at 90 to the first, then half of the atoms will be deflected one way and half the other, so that the atom's spin about the horizontal and vertical axes are independent of each other. However, if one of these beams (e.g. the atoms that were deflected up then left) is passed into a third magnetic field, oriented the same way as the first, half of the atoms will go one way and half the other, even though they all went in the same direction originally. The action of measuring the atoms' spin with respect to a horizontal field has changed their spin with respect to a vertical field.

The Stern-Gerlach experiment demonstrates a number of important features of quantum mechanics:

In 1925, Werner Heisenberg attempted to solve one of the problems that the Bohr model left unanswered, explaining the intensities of the different lines in the hydrogen emission spectrum. Through a series of mathematical analogies, he wrote out the quantum mechanical analogue for the classical computation of intensities.[28] Shortly afterwards, Heisenberg's colleague Max Born realised that Heisenberg's method of calculating the probabilities for transitions between the different energy levels could best be expressed by using the mathematical concept of matrices.[note 9]

In the same year, building on de Broglie's hypothesis, Erwin Schrdinger developed the equation that describes the behaviour of a quantum mechanical wave.[29] The mathematical model, called the Schrdinger equation after its creator, is central to quantum mechanics, defines the permitted stationary states of a quantum system, and describes how the quantum state of a physical system changes in time.[30] The wave itself is described by a mathematical function known as a "wave function". Schrdinger said that the wave function provides the "means for predicting probability of measurement results".[31]

Schrdinger was able to calculate the energy levels of hydrogen by treating a hydrogen atom's electron as a classical wave, moving in a well of electrical potential created by the proton. This calculation accurately reproduced the energy levels of the Bohr model.

In May 1926, Schrdinger proved that Heisenberg's matrix mechanics and his own wave mechanics made the same predictions about the properties and behaviour of the electron; mathematically, the two theories had an underlying common form. Yet the two men disagreed on the interpretation of their mutual theory. For instance, Heisenberg accepted the theoretical prediction of jumps of electrons between orbitals in an atom,[32] but Schrdinger hoped that a theory based on continuous wave-like properties could avoid what he called (as paraphrased by Wilhelm Wien) "this nonsense about quantum jumps."[33]

Bohr, Heisenberg and others tried to explain what these experimental results and mathematical models really mean. Their description, known as the Copenhagen interpretation of quantum mechanics, aimed to describe the nature of reality that was being probed by the measurements and described by the mathematical formulations of quantum mechanics.

The main principles of the Copenhagen interpretation are:

Various consequences of these principles are discussed in more detail in the following subsections.

Suppose it is desired to measure the position and speed of an object for example a car going through a radar speed trap. It can be assumed that the car has a definite position and speed at a particular moment in time. How accurately these values can be measured depends on the quality of the measuring equipment if the precision of the measuring equipment is improved, it will provide a result that is closer to the true value. It might be assumed that the speed of the car and its position could be operationally defined and measured simultaneously, as precisely as might be desired.

In 1927, Heisenberg proved that this last assumption is not correct.[35] Quantum mechanics shows that certain pairs of physical properties, such as for example position and speed, cannot be simultaneously measured, nor defined in operational terms, to arbitrary precision: the more precisely one property is measured, or defined in operational terms, the less precisely can the other. This statement is known as the uncertainty principle. The uncertainty principle isn't only a statement about the accuracy of our measuring equipment, but, more deeply, is about the conceptual nature of the measured quantities the assumption that the car had simultaneously defined position and speed does not work in quantum mechanics. On a scale of cars and people, these uncertainties are negligible, but when dealing with atoms and electrons they become critical.[36]

Heisenberg gave, as an illustration, the measurement of the position and momentum of an electron using a photon of light. In measuring the electron's position, the higher the frequency of the photon, the more accurate is the measurement of the position of the impact of the photon with the electron, but the greater is the disturbance of the electron. This is because from the impact with the photon, the electron absorbs a random amount of energy, rendering the measurement obtained of its momentum increasingly uncertain (momentum is velocity multiplied by mass), for one is necessarily measuring its post-impact disturbed momentum from the collision products and not its original momentum. With a photon of lower frequency, the disturbance (and hence uncertainty) in the momentum is less, but so is the accuracy of the measurement of the position of the impact.[37]

The uncertainty principle shows mathematically that the product of the uncertainty in the position and momentum of a particle (momentum is velocity multiplied by mass) could never be less than a certain value, and that this value is related to Planck's constant.

Wave function collapse is a forced expression for whatever just happened when it becomes appropriate to replace the description of an uncertain state of a system by a description of the system in a definite state. Explanations for the nature of the process of becoming certain are controversial. At any time before a photon "shows up" on a detection screen it can only be described by a set of probabilities for where it might show up. When it does show up, for instance in the CCD of an electronic camera, the time and the space where it interacted with the device are known within very tight limits. However, the photon has disappeared, and the wave function has disappeared with it. In its place some physical change in the detection screen has appeared, e.g., an exposed spot in a sheet of photographic film, or a change in electric potential in some cell of a CCD.

Because of the uncertainty principle, statements about both the position and momentum of particles can only assign a probability that the position or momentum will have some numerical value. Therefore, it is necessary to formulate clearly the difference between the state of something that is indeterminate, such as an electron in a probability cloud, and the state of something having a definite value. When an object can definitely be "pinned-down" in some respect, it is said to possess an eigenstate.

In the Stern-Gerlach experiment discussed above, the spin of the atom about the vertical axis has two eigenstates: up and down. Before measuring it, we can only say that any individual atom has equal probability of being found to have spin up or spin down. The measurement process causes the wavefunction to collapse into one of the two states.

The eigenstates of spin about the vertical axis are not simultaneously eigenstates of spin about the horizontal axis, so this atom has equal probability of being found to have either value of spin about the horizontal axis. As described in the section above, measuring the spin about the horizontal axis can allow an atom which was spin up to become spin down: measuring its spin about the horizontal axis collapses its wave function into one of the eigenstates of this measurement, which means it is no longer in an eigenstate of spin about the vertical axis, so can take either value.

In 1924, Wolfgang Pauli proposed a new quantum degree of freedom (or quantum number), with two possible values, to resolve inconsistencies between observed molecular spectra and the predictions of quantum mechanics. In particular, the spectrum of atomic hydrogen had a doublet, or pair of lines differing by a small amount, where only one line was expected. Pauli formulated his exclusion principle, stating that "There cannot exist an atom in such a quantum state that two electrons within [it] have the same set of quantum numbers."[38]

A year later, Uhlenbeck and Goudsmit identified Pauli's new degree of freedom with the property called spin whose effects were observed in the SternGerlach experiment.

Bohr's model of the atom was essentially a planetary one, with the electrons orbiting around the nuclear "sun." However, the uncertainty principle states that an electron cannot simultaneously have an exact location and velocity in the way that a planet does. Instead of classical orbits, electrons are said to inhabit atomic orbitals. An orbital is the "cloud" of possible locations in which an electron might be found, a distribution of probabilities rather than a precise location.[38] Each orbital is three dimensional, rather than the two dimensional orbit, and is often depicted as a three-dimensional region within which there is a 95 percent probability of finding the electron.[39]

Schrdinger was able to calculate the energy levels of hydrogen by treating a hydrogen atom's electron as a wave, represented by the "wave function" , in an electric potential well, V, created by the proton. The solutions to Schrdinger's equation are distributions of probabilities for electron positions and locations. Orbitals have a range of different shapes in three dimensions. The energies of the different orbitals can be calculated, and they accurately match the energy levels of the Bohr model.

Within Schrdinger's picture, each electron has four properties:

The collective name for these properties is the quantum state of the electron. The quantum state can be described by giving a number to each of these properties; these are known as the electron's quantum numbers. The quantum state of the electron is described by its wave function. The Pauli exclusion principle demands that no two electrons within an atom may have the same values of all four numbers.

The first property describing the orbital is the principal quantum number, n, which is the same as in Bohr's model. n denotes the energy level of each orbital. The possible values for n are integers:

The next quantum number, the azimuthal quantum number, denoted l, describes the shape of the orbital. The shape is a consequence of the angular momentum of the orbital. The angular momentum represents the resistance of a spinning object to speeding up or slowing down under the influence of external force. The azimuthal quantum number represents the orbital angular momentum of an electron around its nucleus. The possible values for l are integers from 0 to n 1 (where n is the principal quantum number of the electron):

The shape of each orbital is usually referred to by a letter, rather than by its azimuthal quantum number. The first shape (l=0) is denoted by the letter s (a mnemonic being "sphere"). The next shape is denoted by the letter p and has the form of a dumbbell. The other orbitals have more complicated shapes (see atomic orbital), and are denoted by the letters d, f, g, etc.

The third quantum number, the magnetic quantum number, describes the magnetic moment of the electron, and is denoted by ml (or simply m). The possible values for ml are integers from l to l (where l is the azimuthal quantum number of the electron):

The magnetic quantum number measures the component of the angular momentum in a particular direction. The choice of direction is arbitrary, conventionally the z-direction is chosen.

The fourth quantum number, the spin quantum number (pertaining to the "orientation" of the electron's spin) is denoted ms, with values +12 or 12.

The chemist Linus Pauling wrote, by way of example:

In the case of a helium atom with two electrons in the 1s orbital, the Pauli Exclusion Principle requires that the two electrons differ in the value of one quantum number. Their values of n, l, and ml are the same. Accordingly they must differ in the value of ms, which can have the value of +12 for one electron and 12 for the other."[38]

It is the underlying structure and symmetry of atomic orbitals, and the way that electrons fill them, that leads to the organisation of the periodic table. The way the atomic orbitals on different atoms combine to form molecular orbitals determines the structure and strength of chemical bonds between atoms.

In 1928, Paul Dirac extended the Pauli equation, which described spinning electrons, to account for special relativity. The result was a theory that dealt properly with events, such as the speed at which an electron orbits the nucleus, occurring at a substantial fraction of the speed of light. By using the simplest electromagnetic interaction, Dirac was able to predict the value of the magnetic moment associated with the electron's spin, and found the experimentally observed value, which was too large to be that of a spinning charged sphere governed by classical physics. He was able to solve for the spectral lines of the hydrogen atom, and to reproduce from physical first principles Sommerfeld's successful formula for the fine structure of the hydrogen spectrum.

Dirac's equations sometimes yielded a negative value for energy, for which he proposed a novel solution: he posited the existence of an antielectron and of a dynamical vacuum. This led to the many-particle quantum field theory.

The Pauli exclusion principle says that two electrons in one system cannot be in the same state. Nature leaves open the possibility, however, that two electrons can have both states "superimposed" over each of them. Recall that the wave functions that emerge simultaneously from the double slits arrive at the detection screen in a state of superposition. Nothing is certain until the superimposed waveforms "collapse". At that instant an electron shows up somewhere in accordance with the probability that is the square of the absolute value of the sum of the complex-valued amplitudes of the two superimposed waveforms. The situation there is already very abstract. A concrete way of thinking about entangled photons, photons in which two contrary states are superimposed on each of them in the same event, is as follows:

Imagine that the superposition of a state that can be mentally labeled as blue and another state that can be mentally labeled as red will then appear (in imagination, of course) as a purple state. Two photons are produced as the result of the same atomic event. Perhaps they are produced by the excitation of a crystal that characteristically absorbs a photon of a certain frequency and emits two photons of half the original frequency. So the two photons come out "purple." If the experimenter now performs some experiment that will determine whether one of the photons is either blue or red, then that experiment changes the photon involved from one having a superposition of "blue" and "red" characteristics to a photon that has only one of those characteristics. The problem that Einstein had with such an imagined situation was that if one of these photons had been kept bouncing between mirrors in a laboratory on earth, and the other one had traveled halfway to the nearest star, when its twin was made to reveal itself as either blue or red, that meant that the distant photon now had to lose its "purple" status too. So whenever it might be investigated after its twin had been measured, it would necessarily show up in the opposite state to whatever its twin had revealed.

In trying to show that quantum mechanics was not a complete theory, Einstein started with the theory's prediction that two or more particles that have interacted in the past can appear strongly correlated when their various properties are later measured. He sought to explain this seeming interaction in a classical way, through their common past, and preferably not by some "spooky action at a distance." The argument is worked out in a famous paper, Einstein, Podolsky, and Rosen (1935; abbreviated EPR), setting out what is now called the EPR paradox. Assuming what is now usually called local realism, EPR attempted to show from quantum theory that a particle has both position and momentum simultaneously, while according to the Copenhagen interpretation, only one of those two properties actually exists and only at the moment that it is being measured. EPR concluded that quantum theory is incomplete in that it refuses to consider physical properties which objectively exist in nature. (Einstein, Podolsky, & Rosen 1935 is currently Einstein's most cited publication in physics journals.) In the same year, Erwin Schrdinger used the word "entanglement" and declared: "I would not call that one but rather the characteristic trait of quantum mechanics."[40] The question of whether entanglement is a real condition is still in dispute.[41] The Bell inequalities are the most powerful challenge to Einstein's claims.

The idea of quantum field theory began in the late 1920s with British physicist Paul Dirac, when he attempted to quantise the electromagnetic field a procedure for constructing a quantum theory starting from a classical theory.

A field in physics is "a region or space in which a given effect (such as magnetism) exists."[42] Other effects that manifest themselves as fields are gravitation and static electricity.[43] In 2008, physicist Richard Hammond wrote that

Sometimes we distinguish between quantum mechanics (QM) and quantum field theory (QFT). QM refers to a system in which the number of particles is fixed, and the fields (such as the electromechanical field) are continuous classical entities. QFT ... goes a step further and allows for the creation and annihilation of particles . . . .

He added, however, that quantum mechanics is often used to refer to "the entire notion of quantum view."[44]:108

In 1931, Dirac proposed the existence of particles that later became known as antimatter.[45] Dirac shared the Nobel Prize in Physics for 1933 with Schrdinger, "for the discovery of new productive forms of atomic theory."[46]

On its face, quantum field theory allows infinite numbers of particles, and leaves it up to the theory itself to predict how many and with which probabilities or numbers they should exist. When developed further, the theory often contradicts observation, so that its creation and annihilation operators can be empirically tied down. Furthermore, empirical conservation laws like that of mass-energy suggest certain constraints on the mathematical form of the theory, which are mathematically speaking finicky. The latter fact both serves to make quantum field theories difficult to handle, but has also lead to further restrictions on admissible forms of the theory; the complications are mentioned below under the rubrik of renormalization.

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Introduction to quantum mechanics - Wikipedia

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by John Assaraf,

Nobel Prize winning physicists have proven beyond doubt that the physical world is one large sea of energy that flashes into and out of being in milliseconds, over and over again.

This is the world of Quantum Physics.

They have proven that thoughts are what put together and hold together this ever-changing energy field into the objects that we see.

So why do we see a person instead of a flashing cluster of energy?

A movie is a collection of about 24 frames a second. Each frame is separated by a gap. However, because of the speed at which one frame replaces another, our eyes get cheated into thinking that we see a continuous and moving picture.

A TV tube is simply a tube with heaps of electrons hitting the screen in a certain way, creating the illusion of form and motion.

This is what all objects are anyway. You have 5 physical senses (sight, sound, touch, smell, and taste).

Each of these senses has a specific spectrum (for example, a dog hears a different range of sound than you do; a snake sees a different spectrum of light than you do; and so on).

In other words, your set of senses perceives the sea of energy from a certain limited standpoint and makes up an image from that.

It is not complete, nor is it accurate. It is just an interpretation.

All of our interpretations are solely based on the internal map of reality that we have, and not the real truth. Our map is a result of our personal lifes collective experiences.

Our thoughts are linked to this invisible energy and they determine what the energy forms. Your thoughts literally shift the universe on a particle-by-particle basis to create your physical life.

Look around you.

Everything you see in our physical world started as an idea, an idea that grew as it was shared and expressed, until it grew enough into a physical object through a number of steps.

You literally become what you think about most.

Your life becomes what you have imagined and believed in most.

The world is literally your mirror, enabling you to experience in the physical plane what you hold as your truth until you change it.

Quantum physics shows us that the world is not the hard and unchangeable thing it may appear to be. Instead, it is a very fluid place continuously built up using our individual and collective thoughts.

What we think is true is really an illusion, almost like a magic trick.

Fortunately we have begun to uncover the illusion and most importantly, how to change it.

Nine systems comprise the human body including Circulatory, Digestive, Endocrine, Muscular, Nervous, Reproductive, Respiratory, Skeletal, and Urinary.

Tissues and organs.

Cells.

Molecules.

Atoms.

Sub-atomic particles.

Energy!

You and I are pure energy-light in its most beautiful and intelligent configuration. Energy that is constantly changing beneath the surface and you control it all with your powerful mind.

If you could see yourself under a powerful electron microscope and conduct other experiments on yourself, you would see that you are made up of a cluster of ever-changing energy in the form of electrons, neutrons, photons and so on.

So is everything else around you. Quantum physics tells us that it is the act of observing an object that causes it to be there where and how we observe it.

An object does not exist independently of its observer! So, as you can see, your observation, your attention to something, and your intention, literally creates that thing.

This is scientific and proven.

Your world is made of spirit, mind and body.

Each of those three, spirit, mind and body, has a function that is unique to it and not shared with the other. What you see with your eyes and experience with your body is the physical world, which we shall call Body. Body is an effect, created by a cause.

This cause is Thought.

Body cannot create. It can only experience and be experienced that is its unique function.

Thought cannot experience it can only make up, create and interpret. It needs a world of relativity (the physical world, Body) to experience itself.

Spirit is All That Is, that which gives Life to Thought and Body.

Body has no power to create, although it gives the illusion of power to do so. This illusion is the cause of much frustration. Body is purely an effect and has no power to cause or create.

The key with all of this information is how do you learn to see the universe differently than you do now so that you can manifest everything you truly desire.

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Tags: electrons, energy, EVERYTHING Is Energy, illusion, magic, particles, Physics, quantum physics, The World Of Quantum Physics, The World Of Quantum Physics: EVERYTHING Is Energy

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The World Of Quantum Physics: EVERYTHING Is Energy : In5D ...