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Quantum Physics: Are Entangled Particles Connected Via An Undetected Dimension? Forbes The informed reader will note a stunning parallel with the ultraviolet catastrophe which led to quantum theory. This term, discussed elsewhere, refers to the fact that using Maxwell's equations and classic mechanics, we get spontaneous infinite ...

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Quantum Physics: Are Entangled Particles Connected Via An Undetected Dimension? - Forbes

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In Erwin Schrodingers thought experiment, the hypothetical cat can either be alive or dead at the same time in a quantum phenomenon known as superposition.

Physicists have now found a way to carry out the experiment and reveal the exact point that objects can switch between classical physics and quantum physics physics on a subatomic scale.

Team leader Alexander Lvovsky, from the University of Calgary and the Russian Quantum Centre, said: "One of the fundamental questions of physics is the boundary between the quantum and classical worlds.

Can quantum phenomena, provided ideal conditions, be observed in macroscopic objects?

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"Theory gives no answer to this question - maybe there is no such boundary.

What we need is a tool that will probe it.

In the researchers experiment, two coherent light waves represented Schrodingers cat for which the fields of the electromagnetic waves pointed in opposite directions at the same time.

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The University of Calgarys Anastasia Pushkina, co-author of the research, said: In essence, we cause interference of two 'cats' on a beam splitter.

This leads to an entangled state in the two output channels of that beam splitter.

In one of these channels, a special detector is placed.

In the event this detector shows a certain result, a 'cat' is born in the second output whose energy is more than twice that of the initial one.

When the team measured the results, they found that they could convert a pair of negative Schrodingers cats with an amplitude of 1.15 to a single positive cat with an amplitude of 1.85 in steps which could have huge implications for the quantum physics.

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The X-ray caused a sensation when it was discovered by German scientist Prof. Roentgen in 1895. He was awarded the first Nobel Prize for physics in 1901. Pictured below are X-rays of the hands of King George and Queen Mary, 1896 / Pics: SSPL

Demid Sychev, a graduate student from the Russian Quantum Centre, added: It is important that the procedure can be repeated: new 'cats' can, in turn, be overlapped on a beam splitter, producing one with even higher energy, and so on.

"Thus, it is possible to push the boundaries of the quantum world step by step, and eventually to understand whether it has a limit."

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Scientists 'BREED' Schrodinger's Cat in massive quantum physics breakthrough - Express.co.uk

Entangled cats? Stranger things could happen if quantum rules scaled up to the everyday world.

Ryan Schneider / Getty

What is the limit to self-contradiction? The question arises in politics and quantum physics alike.

A team of Russian and Canadian physicists have figured out how to push the limits of self-contradicting quantum states, by breeding Schrdingers cats.

Their experiment, which involves sending cat-state photons through a hall of mirrors which multiplies their number, is described in Nature Photonics today.

Using the new method, the authors hope to help answer a fundamental question, namely: at what scale does the absurdity of quantum mechanics end and common-sense reality begin?

In the microscopic world of quantum mechanics, particles can do seemingly impossible things: such as being simultaneously in two contradictory states at once. For the Austrian physicist Erwin Schrdinger, who helped put quantum mechanics on firm foundations in 1926 with his Nobel- winning equation, this idea was too crazy to be believed.

In 1935, to illustrate how absurd quantum ideas had become, Schrdinger came up with a scenario involving a cat which, according to quantum theory, is both alive and dead at the same time.

The way he did it was to link the fate of a cat to a specific quantum event.

With ingenuity more typical of a Bond villain than a physicist, Schrdinger imagined a cat trapped inside a steel box along with some radioactive material, a Geiger counter, a hammer and a vial of hydrogen cyanide. If one of the radioactive atoms decays a chance quantum event it would trigger the hammer to smash the vial of poisonous gas, and farewell Felix.

Before you open the box to check, says quantum theory, the radioactive atom is both decayed and not-decayed. By extension, said Schrdinger, the cat is both alive and deadthe distinction between them blurry and smeared out.

But what seemed impossible to Schrdinger, is a commonplace for modern day physicists, who have worked out how to produce various analogues of Schrdingers cat in real physical systems. They are used in many quantum technologies including quantum computation, teleportation, and cryptography.

In essence, a particle in a Schrdingers cat state is one that is holding two contradictory states at once. For example, an electron could be simultaneously spin up and spin down. Or, a photon of light could be simultaneously waving in two opposite directions.

Until now, experimenters have only managed to muster small groups of Schrdingers cat photons with limited energies, but the new work creates any number by breeding them.

The method works by taking two photons, already in cat states, and firing them simultaneously through the same beam-splitter, which gets the two photons entangled. After some more beam-splitting the arrangement spits out more cat states than went in a bit like if Felix hopped through a cat-flap and two cats appeared on the other side.

The snag is, the process only works about one fifth of the time. (The rest of the time, there's no entanglement, and no breeding of cats.)

And running the photons through the ring again would increase the amplitude even further. Using this iterative approach could potentially produce as many quantum cat states as you like.

Thus, it is possible to push the boundaries of the quantum world step by step, and eventually to understand whether it has a limit, says Demid Sychev, of the Russian Quantum Center and the Moscow State Pedagogical University, and lead author of the study.

Meanwhile, the debate which originated with Schrdinger, Bohr and Einstein continues today: the question of whether the universe is innately fuzzy or whether it is just the way we see it. As Schrdinger eloquently put it in 1935: There is a difference between a shaky or out-of-focus photograph and a snapshot of clouds and fog banks.

Producing quantum phenomena with more particles, and in larger scales, might just help us spot the difference between these two pictures, and finally get to grips with reality.

Even if our politicians still struggle with it.

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Physicists breed Schrdinger's cats to find boundaries of the | Cosmos - Cosmos

May 1, 2017 ThALES. Credit: R. Cubitt, ILL

In modern physics of the past century, understanding the electronic properties and interactions between electrons inside matter has been a major challenge. Electrons are responsible for the chemical link between atoms and almost all factors that characterise a piece of matter, such as colour, heat transport, conductivity and magnetism. An elementary property of electrons is the spin, and the combination of electronic spins on the atomic level can induce a magnetic moment on certain atoms, which constitute the material. These moments can add up to macroscopic magnetic forces.

As magnetism is the footprint of the interactive behaviour of electrons, studying it on the atomic level informs us about the collective electronic behaviour in the atomic environment. This can explain macroscopically observed electronic properties, like the temperature dependence of the conductivity.

On the atomic level, magnetic ions are closely packed and thus mutually influence each other, resulting in the adoption of a common magnetic order to minimise their energy balance. A slight perturbation leads to a spin wave, whereby an oscillation of one magnetic moment around its central axis induces oscillating perturbations with a slight phase shift on the atomic neighbours. Spin waves are routinely observed in ordered magnetic materials by inelastic neutron scattering (INS) on spectrometers at the Institut Laue-Langevin (ILL).

Transitioning from a classical to a quantum magnetic world

The magnetic moment is characterised by its spin number. The larger the spin number, the more appropriate it is to compare the atomic magnetic moment with a classical magnet. Lowering the spin means accentuating its quantum properties; exploring the transition into the quantum world, which is fundamentally different from the daily, macroscopic world, is one of the most exciting challenges in solid state physics.

The most cited example is the spin -1/2 moments placed in the corner of an equidistant triangle. Due to its quantum nature, one spin can only point upwards or downwards with respect to its local axis. A magnetic exchange between the spin moments, that is antiferromagnetic in nature, forces them to align antiparallel to each other. As a quantum magnet cannot order, rather than adopting one ground state, several states are equally likely (6 in the case of the triangle), and the spins are in a super-positioned state pointing in several directions at once.

Combining equidistant triangles leads to a two-dimensional network of spins. Its ground state, i.e. the spin arrangement with the lowest possible energy cost, has challenged theorists for decades. In 1973, noble laureate P.W. Anderson proposed a so-called 'quantum spin liquid state,' which is conceptually completely different to ordered magnetic phases. Anderson argued that for a triangular system, it is energetically more favourable for spins to organise into bonds. In these valence bonds, electrons are quantum mechanically 'entangled,' a purely quantum mechanical state. A superposition of a manifold of bond pattern exists in parallel and bonds fluctuate due to a quantum mechanical principle, which imposes zero point motions on the particles. This state is called a Resonant Valence Bond (RVB) state.

Neutron scattering provides experimental proof for the RVB state

Here at ILL, two cold three-axis spectrometers, IN14 and IN12, contributed over decades to the discovery and unravelling of magnetic correlations in classical and non-conventional superconductors, multiferroic crystals and a wide range of low-dimensional, frustrated and quantum magnetic systems. As both instruments dated from the 1980s, they were in need of a complete refurbishment to be able to continue contributing to the scientific progress in these fields. The new IN12 spectrometer's relocation and refurbishment was completed in 2012, and by the end of 2014, the IN14 spectrometer was replaced by its successor, ThALES.

ThALES, Three-Axis instrument for Low Energy Spectroscopy, is a next generation cold neutron three-axis spectrometer that builds on the strengths of its predecessor, IN14, but uses state-of-the-art neutron optics. The ThALES project is a collaboration between ILL and Charles University, Prague, and is financed by the Czech Ministry of Science and Education.

After replacing the IN14, ThALES became the new reference for cold single crystal neutron spectroscopy at a steady state neutron source like the ILL reactor. ThALES has been fully optimised to address the physics of highly correlated electron systems and scientific problems in the field of quantum magnetism. Moreover, the flexibility of the spectrometer has been enhanced through the implementation of various optical elements.

The key aims of ThALES are:

ThALES was used to carry out INS measurements in a recent study conducted by a collaboration of scientists, including ILL's Martin Boehm, current co-ordinator of the EU-funded neutron network SINE2020. The study published in Nature, titled 'Evidence for a spinon Fermi surface in a triangular lattice quantum-spin-liquid candidate,' argued that the triangular-lattice antiferromagnet YbMgGaO4 has the long sought quantum spin liquid RVB ground state. This study was the first to use neutron scattering as a means of providing experimental proof for the RVB state.

The experimental effort to discover the RVB ground state has considerably increased since P.W. Anderson suggested that it might explain the phenomenon of superconductivity in a class of materials that show particularly high transition temperatures between a normal conducting and superconducting state. However, providing experimental proof for the existence of the RVB state is very challenging, because while a magnetically ordered system has a clear experimental response, the RVB state is characterised by the absence of a measurable quantity.

Due to the lack of a measurable quantity, the experimental approach of this study, using ThALES, selected indirect experimental proof by deliberately exciting the ground state with neutrons and measuring the dynamic response. According to theoretical expectations, the excited spin liquid behaves 'exotically,' meaning the excited state is explained by spinons with very unusual properties. Spinons can rearrange the distribution of valence bonds and travel throughout the triangular plane with a minimum amount of energy.

In a scattering process between the neutron and the spin liquid, the law of conservation of total momentum imposes the creation of two spin-1/2 spinons in the liquid. This pair of spinons travel in opposite directions with a total amount of energy equalling the loss of neutron energy in the scattering process. Using the ThALES spectrometer, it is possible to trace the direction and energies of the spinons by measuring the direction and energy of the neutron that created the spinon pair. In this way, this study traced a complete dynamical landscape of the spin quantum liquid in the triangular plane, and compared the measurements with theoretical predictions, which gave strong evidence for the existence of the spin liquid phase in YbMgGaO4.

This research is important as a quantum spin liquid state of matter is potentially relevant for applications of quantum information. Moreover, experimental identification of a quantum spin liquid state contributes greatly to our understanding of quantum matter.

Explore further: Novel state of matter: Observation of a quantum spin liquid

More information: Yao Shen et al. Evidence for a spinon Fermi surface in a triangular-lattice quantum-spin-liquid candidate, Nature (2016). DOI: 10.1038/nature20614

Journal reference: Nature

Provided by: Institut Laue-Langevin

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Electrons are repelled by other electrons (Coulomb's Law). This is the opposite of a "bond". Electrons are attracted by protons. The most simple atom is Hydrogen. This is a very engaging subject, which I have studied since 1989. Max Planck's original quantum theory was based on the hydrogen atom as an electronic system, and there were no conflicts. My book ("The Secret of Gravity", 1997) presents proof that gravity is an electronic force. The dynamic forces of hydrogen atoms can be analyzed using special computer programs ("Analyzing Atoms Using the SPICE Computer Program", Computing in Science and Engineering, Vol. 14, No. 3, May/June 2012). An electronic model of the hydrogen atom is presented and analyzed.

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The application of three-axis low energy spectroscopy in quantum physics research - Phys.Org