Category Archives: Quantum Physics

Classification: Academic Level ESalary package: $183,749 per annum plus 17% SuperannuationTerm:Full Time, Fixed Term (5 years)Position Description & Selection Criteria:SmartSat_Booklet_Final02062022__V2.pdf

The ANU College of Science (CoS) comprises: the Research School of Astronomy and Astrophysics, the Research School of Biology, the Research School of Chemistry, the Research School of Earth Science, the Fenner School of Environment and Society, the Mathematical Sciences Institute, the Research School of Physics, and the Centre for the Public Awareness of Science. Staff and students within the ANU College of Science conduct research and deliver a research-led education program that encompasses the entire breadth of the sciences, supported by extensive international networks and by world-class facilities. The College has a strong tradition of research excellence that has fostered distinguished Nobel Laureates and Kyoto Prize winners and that trains scientific leaders in disciplines in which the ANU is consistently ranked in the top twenty in the world.

The Research School of Physics (RSPhys)represents Australia's largest university-based research and teaching activity in the physics discipline. Fields of research include quantum physics, nuclear physics, electronic materials engineering, photonic and meta-optic materials, computational and theoretical physics. The underlying impetus of our research is a belief in the fundamental important of physics to science and technology and the key role physics must play in addressing the challenges facing the modern world. We tackle these challenges by collaborating widely across academia as well as with government and industry. The School has a longstanding culture of precision measurement with a strength in quantum phenomena and is involved in six Australian Research Council (ARC) Centres of Excellence contributing richly to quantum, optical and electronic technologies.There is no better place to study and research physics than the Research School of Physics at The Australian National University.

The ANU Institute for Space (InSpace) is the gateway to University wide space capability via a single innovation institute. The institute resides in the ANU DVCR&I portfolio.

As a a member of Research School of Physics, accountable to the Head, Department of Quantum Science and Technology. This position will work closely with the SmartSat CRC to develop fundamental and translational research related to precision measurement in the space environment, and via membership of the ANU Institute for Space, will continue to ensure strong synergies between the University and SmartSat.

A substantial start-up will be made available to the Chair to be used in agreement with SmartSat in the development and delivery of SmartSat R&D projects which deliver on the SmartSat research milestones, building capability and developing proposals in attracting additional funding for SmartSat and the ANU.

The Australian National University is a world-leading institution and provides a range of lifestyle, financial and non-financial rewards and programs to support staff in maintaining a healthy work/life balance whilst encouraging success in reaching their full career potential. For more information, please click here.

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For more information about the position please contact Professor Tim Senden on T: +61 2 61252476 E: Director.Physics@anu.edu.au

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Application information

In order to apply for his role, please make sure that you upload the following documents:

Applications which do not address the selection criteria may not be considered for the position.

Please note: The successful applicant must have rights to live and work in this country.

The successful candidate will be required to undergo a background check during the recruitment process. An offer of employment is conditional on satisfactory results.

Closing Date: 22 June 2022

Continued here:

Professor, SmartSat Chair in precision measurement in Space job with AUSTRALIAN NATIONAL UNIVERSITY (ANU) | 296545 - Times Higher Education

image:A cascade of particles and gluons initiated by a decelerating charm quark. The more developed the cascade, the lower the energies of secondary particles and the greater the opening angle of dead cones avoided by subsequent gluons. view more

Credit: Source: CERN

A phenomenon that directly proves the existence of quark mass has been observed for the first time in extremely energetic collisions of lead nuclei. A team of physicists working on the ALICE detector at the Large Hadron Collider can boast this spectacular achievement the observation of the dead cone effect.

The objects that make up our physical everyday life can have many different properties. Among these, a fundamental role is played by mass. Despite being so fundamental, mass has a surprisingly complex origin. Its primary source is the complex interactions binding triplets of quarks in the interiors of protons and neutrons. In modern physics it is assumed that the masses of the quarks themselves, originating from their interactions with the Higgs field (its manifestations are the famous Higgs bosons), contribute only a few percent to the mass of a proton or neutron. However, this has only been a hypothesis. Although the masses of single quarks have been determined from measurements for many years, only indirect methods were used. Now, thanks to the efforts of scientists and engineers working in Geneva at the LHC of the European Organization for Nuclear Research (CERN), it has finally been possible to observe a phenomenon that directly proves the existence of the mass of one of the heavy quarks.

When lead nuclei collide at the LHC particle accelerator, the energy density can become so great that protons and neutrons decay and momentarily form quark-gluon plasma. The quarks inside then move in a powerful field of strong interactions and begin to lose energy by emitting gluons. However, they do this in a rather peculiar way, which our team was the first to succeed in observing, Prof. Marek Kowalski from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow starts to explain. Prof. Kowalski is one of the members of a large international collaboration carrying out measurements using the ALICE detector.

Gluons are particles that carry strong interactions between quarks. Their role is therefore similar to that of photons, which are responsible for the electromagnetic interactions between, for example, electrons. In electrodynamics, there is a phenomenon concerning electrons decelerating in an electromagnetic field: they lose energy by emitting photons and the higher the energy of the electron, the more often the photons fly in a direction increasingly consistent with its direction of motion. This effect is the basis of free-electron lasers today unique, powerful devices capable of producing ultra-short pulses of X-rays.

Electrons decelerating in a magnetic field like to emit 'forward' photons, in an angular cone. The higher their original energy, the narrower the cone. Quarks have quite the opposite predilection. When they lose energy in a field of strong interactions, they emit gluons, but the lower the energy and the larger the mass of the quark, the fewer gluons fly 'forward', says Prof. Kowalski and specifies: It follows from the theory that there should be a certain angular cone around the direction ofquark motion in which gluons do not appear. This cone the more divergent, the lower the energy of the quark and the higher its mass is called the dead cone.

Theorists predicted the phenomenon of the dead cone more than 30 years ago. Unfortunately, its existence in experiments has so far been noticed only indirectly. Both the nature of the phenomenon and the recording process are extremely difficult to observe directly. A decelerating quark emits gluons, which themselves can emit further gluons at different angles or transform into secondary particles. These particles have smaller and smaller energies, so the gluons they emit will avoid larger and larger dead cones. To make matters worse, individual detectors can only record this complex cascade in its final state, at different distances from the collision point, and therefore at different times. To observe the dead cone effect, millions of cascades produced by charm quarks had to be reconstructed from fragmentary data. The analysis, performed with sophisticated statistical tools, included data collected during the three years the LHC was in operation.

Experimental confirmation of the existence of the dead cone phenomenon is an achievement of considerable physical significance. This is because the world of quarks and gluons is governed by strong interactions described by a theory called quantum chromodynamics, which predicts that the dead cone effect can only occur when a quark emitting gluons has non-zero mass. The present result, published in the prestigious journal Nature, is therefore the first direct experimental confirmation of the existence of quark masses.

In the gigantic amount of data collected at the ALICE detector during the collision of lead nuclei and protons, we have traced a phenomenon that we know can only occur in nature when quarks have non-zero masses. Current measurements do not allow us to estimate the magnitude of the mass of the charm quarks we observed, nor do they tell us anything about the masses of quarks of other kinds. So we have a spectacular success, but in fact it is only a prelude to a long line of research, stresses Prof. Kowalski.

The first direct observation of the dead cone effect involved only gluons emitted by charm (c) quarks. Scientists now intend to look for dead cones in processes involving quarks with larger masses, especially beauty (b) quarks. This will be a huge challenge because the higher the mass ofthe quark, the less frequently it is produced in collisions, and therefore the more difficult it will be to collect a number of cases that will guarantee adequate reliability of statistical analyses.

The reported research is of fundamental importance to modern physics. This is because the Standard Model is the basic tool currently used to describe phenomena involving elementary particles. Masses of quarks are the key constants here, responsible for the correspondence between theoretical description and physical reality. It is therefore hardly surprising that the observations of dead cones, raising hopes for direct measurements of quark masses, are of such interest to physicists.

The Henryk Niewodniczaski Institute of Nuclear Physics (IFJ PAN) is currently one of the largest research institutes of the Polish Academy of Sciences. A wide range of research carried out at IFJ PAN covers basic and applied studies, from particle physics and astrophysics, through hadron physics, high-, medium-, and low-energy nuclear physics, condensed matter physics (including materials engineering), to various applications of nuclear physics in interdisciplinary research, covering medical physics, dosimetry, radiation and environmental biology, environmental protection, and other related disciplines. The average yearly publication output of IFJ PAN includes over 600 scientific papers in high-impact international journals. Each year the Institute hosts about 20 international and national scientific conferences. One of the most important facilities of the Institute is the Cyclotron Centre Bronowice (CCB), which is an infrastructure unique in Central Europe, serving as a clinical and research centre in the field of medical and nuclear physics. In addition, IFJ PAN runs four accredited research and measurement laboratories. IFJ PAN is a member of the Marian Smoluchowski Krakw Research Consortium: "Matter-Energy-Future", which in the years 2012-2017 enjoyed the status of the Leading National Research Centre (KNOW) in physics. In 2017, the European Commission granted the Institute the HR Excellence in Research award. The Institute holds A+ Category (the highest scientific category in Poland) in the field of sciences and engineering.

CONTACTS:

Prof. Marek Kowalski

Institute of Nuclear Physics, Polish Academy of Sciences

tel.: +48 12 6628074

email: marek.kowalski@cern.ch, marek.kowalski@ifj.edu.pl

SCIENTIFIC PUBLICATIONS:

Direct observation of the dead-cone effect in quantum chromodynamics

ALICE Collaboration

Nature 605, 440446 (2022)

DOI: https://doi.org/10.1038/s41586-022-04572-w

LINKS:

http://www.ifj.edu.pl/

The website of the Institute of Nuclear Physics, Polish Academy of Sciences.

http://press.ifj.edu.pl/

Press releases of the Institute of Nuclear Physics, Polish Academy of Sciences.

IMAGES:

IFJ220609b_fot01s.jpg

HR: http://press.ifj.edu.pl/news/2022/06/09/IFJ220609b_fot01.jpg

A cascade of particles and gluons initiated by a decelerating charm quark. The more developed the cascade, the lower the energies of secondary particles and the greater the opening angle of dead cones avoided by subsequent gluons. (Source: CERN)

Direct observation of the dead-cone effect in quantum chromodynamics

18-May-2022

Read the rest here:

Difficult-to-observe effect confirms the existence of quark mass - EurekAlert

What is our place in the universe? How do we explain what happens around us? These are big questions to ask on our quest to understand the complexities of physics and the universe. Thats why weve curated this round up of the best physics books to gain a deeper understanding from the top authors in the field.

Physics can be a dense and detailed study, with complicated theories and exploration of ideas that can be difficult for anyone to fully comprehend. They explain these concepts in ways that are approachable and will continue your journey of understanding our physical world.

Weve collected the best physics books written by some of the worlds most renowned scientists, including Stephen Hawking, Brian Greene, and Richard Feynman. These are the books that break down complicated matters to simple, easy-to-read concepts, get to the heart of the matter quickly without getting lost in the details, and entertain you along the way with their humor and personal stories.

If you want to discover anything from the origins of physics through to its evolution into the modern century, these are the best physics books to add to your library for all levels of enthusiasts to expand your thinking and knowledge of the way our world works.

If you're looking for physics books that specifically deal with the cosmos, then you can check out our guide to the best astronomy books.

1. The Elegant Universe

Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory

Price: $11.59 (paperback, new)

Author: Brian Greene

Publisher: W. W. Norton & Company

Release date: October 11, 2010

Expertly organized

Uses relatable analogies

Complex topics accessible for those without a scientific background

Later chapters can grow in complexity and may seem daunting

Written by one of the worlds most renowned string theorists, The Elegant Universe takes complex topics and makes them easily accessible to any reader with or without a science background! Greene creates an impactful and visual reading experience as he navigates through the mysteries of the universe. This international bestseller inspired a major Nova special and leans into Greens expertise in superstring theory.

The Elegant Universe brings thoughtful discussion surrounding special relativity, general relativity, and quantum mechanics, paving the way towards an explanation of all forces and matter. Simple analogies and footnotes break down heavier topics with a dash of humor. Readers will be delighted by the approachable way in which Greene ties in string theory to help our understanding of the vast universe.

2. The Feynman Lectures on Physics (box set)

The New Millennium Edition

Price: $115.99 (hardcover, new)

Author: Richard P. Feynman

Publisher: Basic Books

Release date: January 4, 2011

World's greatest lectures still used in universities today

Approachable intro for those interested in the foundations of physics

Expensive, but they are hardcovers

Unmissable content for any student and those eager to learn more about this expansive field who wants a foundational introduction to physics written by beloved Nobel laureate, Richard P. Feynman. The Feynman Lectures on Physics is a collection of his most profound lectures, reprinted and corrected in collaboration with CalTech. Inside this three-book box set, youll find the basic principles of Newtonian physics through more complex topics such as general relativity, quantum mechanics, and beyond.

Feynman's lectures are accessible without sacrificing relevant information. His passion is evident throughout the pages, never shying away from asking the tougher questions and challenging his audience to expand their thinking. This is a box set designed for each generation, setting up the future for emerging scientists.

3. Quantum Mechanics: The Theoretical Minimum (illustrated edition)

What you need to know to start doing physics

Price: $16.33 (paperback, new)

Author: Leonard Susskind and Art Friedman

Publisher: Basic Books

Release date: May 12, 2015

Clear presentation of the inner workings of quantum physics

Includes step-by-step exercises

Requires some prior mathematical knowledge

Need to read first book to better understand this one

Quantum Mechanics: The Theoretical Minimum is the second book in the Theoretical Minimum series. If youre a reader with some knowledge of linear algebra and calculus who wants to dive deeper into the world of quantum mechanics, this is for you. Susskind and Friedman make it easy to follow along with the subject matter, getting to logical explanations quickly. Susskind deploys notations in earnest, condensing information into manageable symbols.

Itll get you thinking about the information differently, trying out a new way to speculate and approach complicated topics. This book will connect the dots, build the bridges between each concept presented, and explain all the core ideas of theory coherently.

4. Thirty Years that Shook Physics

The story of quantum theory

Price: $12.59 (paperback, new)

Author: George Gamow

Publisher: Dover Publications, Inc

Release date: July 1, 1985

Accounts of personal interactions with all the science greats

Interesting look into the history of science and quantum physics

To get the best out of the theories in this book you'll need a good grasp of maths

Gamow possesses an engaging, entertaining way of presenting the very basics of quantum physics and its progression over the span of three decades. As Gamow was personally acquainted with the scientists presented in this book Bohr, Pauli, Dirac, and Heisenberg just to name a few the result is a level of humanity and personality behind the origins of some of physics' most complex theories and equations.

This is a book about how science has changed and developed in the last century, and Gamow writes this in a way that is accessible to a general audience. Covering prominent events between 1900-1930, youll get the inside story on the course that shaped modern physics.

5. A Brief History of Time

Price: $7.99 (paperback, new)

Author: Stephen Hawking

Publisher: Bantam

Release date: September 1, 1998

Filled with images and useful definitions

Short, quick read

Uses basic terminology and avoids over-complicated info dumps

Deeper theories require prior physics knowledge to fully appreciate

Written by the late Stephen Hawking one of the most renowned scientists of this century A Brief History of Time delves into topics such as black holes, wormholes, uncertainty principle, space and time, expansion of the universe, time travel, and so much more.

Hawking manages to be accessible, while still speaking to those with years of scientific experience under their belts. Its quick and to the point, providing clarity around some of the most complex mechanics of how our universe works. Logically organized, humorous at times, and immersive, youll be taken on a journey that spans from our worlds earliest astronomers to the latest on the future of the universe.

6. Seven Brief Lessons on Physics

Price: $12.00 (paperback, new)

Author: Carlo Rovelli

Publisher: Penguin

Release date: January 1, 2012

Short (only 7 chapters)

Perfect for those interested in the foundations of physics

Can be dense in some areas

Hard to find

Carlo Rovelli is a widely respected and renowned theoretical physicist who introduces you to the modern world of physics. Its a short book, with the paperback only coming in at 81 pages, but its packed with playful and entertaining takes on our world and the role we play in it. Moving quickly through Einsteins general relativity, quantum mechanics, and other complexities of our known universe, Seven Brief Lessons outlines how physics arrived to where it is now.

Written confidently and in a way that is accessible to any reader, the intricacies of this book is written with vivid clarity. Beautifully written, and almost lyrical in its presentation of Newton, Bohr, and Einstein, Seven Brief Lessons on Physics is not one to miss.

7. Physics of the Impossible

A Scientific Exploration of the World of Phasers, Force Fields, Teleportation, and Time Travel

Price: $29.82 (hardcover, new)

Author: Michio Kaku

Publisher: Doubleday

Release date: March 11, 2008

Perfect for sci-fi fans

Humorous undertones

Some feel this book is more fantastical rather than focusing on the actual physics

Fans of pop culture will delight in the insights presented in this engaging and humorous book. Michio Kaku, theoretical physicist and bestselling author, explores the possibilities of teleportation, force fields, interstellar spaceships, and other future technologies youve seen only in science fiction. Are they truly as impossible to achieve as it seems?

In this informative yet widely imaginative look at the universe and the laws of physics, the very topic of scientific possibility is on full display. Kaku looks into the several branches of physics from Newtonian mechanics up to relativity and quantum mechanisms of the 20th century. Sci-fi technologies are broken down into accessible ideas as Kaku explores the possibilities of building starships, time travel, and invisibility.

8. Astrophysics for People in a Hurry

Price: $9.49 (hardcover, new)

Author: Neil deGrasse Tyson

Publisher: W. W. Norton & Company

Release date: May 2, 2017

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Clear, concise introduction

Shorter page count

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Best physics books: Change the way you look at the universe - Livescience.com

Quantum TheologyCarl Peterson, physicist

Quantum theory and God? Any connection? Should we construct a quantum theology(OMurchu, 2021)?

Hybrid physicist and theologian, the late John Polkinghorne, would certainly answer in the affirmative: we need quantum theology. Questions of causality ultimately demand metaphysical answering (Polkinghorne, 2006, p. 139). However, such metaphysical answering might not be simple. Why? Because Niels Bohrs Copenhagen version of quantum theory is indeterminist, while David Bohms holistic version is determinist. Whats a theologian to do?

Let me elaborate slightly. Copenhagen indeterminism is observational, not ontological. Bohmian determinism provides an ontology, a comprehensive worldview. Still, we ask, what is a theologian to do about these competing models of quantum mechanics?

Hybrid physicist and theologian Robert John Russell proposes a theological answering with his principle of NIODA (Non-Interventionist Objective Divine Action). Russells quantum theology is based on Copenhagen indeterminism. Still, we ask: might Bohms metaphysical answer and Russells theological answer be compatible? Well ask physicist Carl Peterson.

In this Patheos post, Id like to turn to a controversy youre not likely to learn much about on social media or Patheos. Its the debate among physicists over the interpretation of Quantum Mechanics (QM for short). What happens within the atom at the quantum level? Do those fast moving electrons and photons obey deterministic laws? Or not?

Why is this important? Because exploring sub-atomic physics brings us as close to fundamental to reality as we can get. Thats why. And, mystery of all mysteries, micro-reality seems to be indeterministic. That is, it seems to be. Maybe theres a determinism that is hidden. Mmmmm? Might this affect quantum theology?

So, dear reader, I recommend you bracket out for a few moments any preset views you hold about supernaturalism, miracles, and anti-religious venom. Simply listen in on a controversy within science that could have implications for quantum theology. We will ask as John Horgan in Scientific American asks, What does God, Quantum Mechanics, and Consciousness Have in Common? Our proposed answers will look quite different, let me warn you.

Carl Peterson (Ph.D. Ohio University) is a physicist working both in academia and private industry. He taught physics and chemistry at Ohio Wesleyan University and Columbus State University. He has published on the electronic structure of polyatomic molecules. Today, as an independent scholar, he seeks to break the hegemony of the Copenhagen interpretation of quantum mechanics and advocates instead for David Bohms ontological interpretation in quantum theory.

Carl Peterson is not a quantum theologian. Yet, what he says about physics should make a quantum theologian sit up and take notice.

Our atheist friends keep whining that there is no such thing as a supernatural realm (Atkins, 2006). This means, there is no such thing as a miracle. And, if there are no miracles, then religion is bunk. Curiously, atheists can be just as superstitious as the religious believers they renounce. But, thats another topic.

What is our present topic? Here it is: how does God work in the natural realm without supernatural intervention? The problem with atheists talking about supernaturalism is that they leap and scream like cheer leaders for naturalism. But, theologians are quite happy with studying how God works within the natural world in ordinary ways. So, by staring at the cheer leaders, our atheist friends have not noticed the actual game being played.

When we turn to the actual game being played, we see questions that require both scientists and theologians to address. Here is such a question: how can God act in the natural world providentially yet not supernaturally or miraculously? At the quantum level within the atom, does God act in such a way that we experience it at the level of our human experience?

This is the kind of question asked by my friend and colleague, Robert John Russell. Bob is founder and director of the Center for Theology and the Natural Sciences at the Graduate Theological Union in Berkeley, California. Bob thinks he finds an answer in the indeterministic interpretation of QM.

When we shift to an indeterministic world, a new possibility opens up. One can now speak of objective acts of God that do not require Gods miraculous intervention but offer, instead, an account of objective divine action that is completely consistent with science.(Russell, 2008, p. 128).

Relying on indeterminism at the microlevel, Bob advances his QM-NIODA theory: Quantum Mechanical Non-Interventionist Objective Divine Action. If God acts together with nature to produce the events of objective divine action, God is not acting as a natural, efficient cause(Russell, 2008, p. 128). Or, Essentially what science describes without reference to God is precisely what God, working invisibly in, with, and through the processes of nature, is accomplishing(Russell, 2008, p. 214).

In what follows, Id like to put Bobs theological interpretation of QM to the test. How? By interviewing physicist Carl Peterson. Carl, as you will see, will not grant the indeterminist interpretation of QM put forth by Niels Bohr and the Copenhagen school. What might this mean for Bobs NIODA theory(Russell, The Physics of David Bohm and Its Relevance to Philosophy and Theology, 1985)?

CP.1. I dont believe the indeterminist interpretation at Copenhagen is mistaken. Its just inadequate. Or, better, Bohms ontological interpretation is more adequate.

But first, alittle bit of history about Bohms interpretation!In February of 1951, Bohm published an advanced book that he entitledQuantumTheory (Bohm D. , Quantum Theory, 1951). This book has twenty-three chapters. When one reads the last two chapters, it seems that Bohm accepted Bohrs response to Einstein, Podolsky, and Rosens (EPR) criticisms of quantum mechanics not being complete, in favor of Bohrs indeterminist interpretation.

However, after publishing the book, and discussing it and the EPR criticism about quantum mechanics with Albert Einstein, Bohm started rethinking some of his concepts and statements in the book. Primarily, about hidden variables and the, well known, underlying concerns with the Copenhagen interpretation and its measurement problem. Bohms first two papers setting forth his renewed thoughts on those subjects were received by Physical Review on July 5, 1951. This was four months after the publication of his book. Bohm entitled his papers: A suggested Interpretation of the Quantum Theory in Terms of Hidden Variables I & II (Bohm D. , A Suggested Interpretation of the Quantum Theory in Terms of Hiddon Variables I and II, 1952). In his acknowledgment he thanked Dr. Einstein for several interesting and stimulating discussions.

Now to Bohms Hidden Variables interpretation! Bohm put the wavefunction in the form normally used to have the Schrdinger equation (SE) reduced to classical mechanics. Next he inserted it into the Schrdinger equation (Bohm called the SE the mathematical apparatus). And then, by separating the real and imaginary parts he obtained two equations of motion, one forR, and one forS. However, Bohm did not proceed directly to the classical limit, as is usually done, by setting the quantum of action,h=0, in the equation of motion forSsincehnever equals0.He theorized there might be more microstructure associated with the quantum field than had previously been determined or realized by retaining the quantum of action (That was his visionary move).

The questions arising on suggesting more microstructure became, by producing two equations of motion, that are rigorously equivalent to the SE. What is their physical interpretation? Does the microstructure add to the underlying independent reality of the wavefunction? Does its ontology still lead to agreement with experimental observations? Keep in mind there is no ontology associated with the Copenhagen interpretation. So, Bohm went to work on answering these questions!

TP. Interjection. Recall what Polkinghorne said in the citation above: Questions of causality ultimately demand metaphysical answering(Polkinghorne, 2006, p. 139). Bohms ontology of QM provides such an answer. This ontological interpretation attracts Carl Peterson. TP

CP. Bohm reinterpreted the wavefunction as representing a fundamentally real field described by its amplitude function, R, and its phase function,S.Moreover, there are real particles. And, every real particle is never separated from its quantum field with a well-defined position that varies continuously and is causally determined. Bohm found that the average momentum is related to the phase function. And highly important, Bohm noted every particle in the equation of motion for S containeda classical potential,V, plus an additional term with the quantum of action.Bohm theorized the term could be considered an additional potential, which he called the quantum potential.

Furthermore, the quantum potential is the microstructure which introduces new concepts not considered or even accepted as essential in the structure of classical physics. Lets name a few: a), the quantum potential depends only on the mathematical form of its wavefunction, and not on the intensity of the quantum field. This is different from, for instance, the Newtonian gravitational potential, which tends to decrease with increasing distance apart. b), The reaction of each individual particle may dependnonlocallyon the configuration of the other particles regardless of distance, where the particle position and momenta arehidden variables. c),active information, different from the usual understanding in classical physics as a quantitative measure in communication but understood by Bohms interpretation as a feature of the quantum potential, in which very little energy directs or uses a much greater energy, he gives examples in many of his works, such as radio waves and the DNA molecule, d).Wholeness, whereby every region of space is connected by the quantum potential into an unbroken wholeness or unifying whole. Bohm discusses all these concepts in his book with B. J. Hiley,The Undivided Universe (Bohm D. a., 1994).

The mathematical apparatus still provides the necessary values for observed quantities just as the Copenhagen interpretation does. But it also provides for particles and trajectories in a completely deterministic system. That is, the initial position of a particle uniquely determines its future behavior. And in the words of the late James T. Cushing, which I have memorized, Here we have a logically consistent and empirically adequate deterministic theory of quantum phenomena. And I might add, whats the problem; why dont we use it?

CP.2. You ask: what does this quote from Bohm mean? I really like Bohms personification of his proposed view on the concept ofunbroken wholeness(Bohm D. , Wholeness and the Implicate Order, 1980) for interpreting two significant, as well as necessary, discoveries of twentieth century physics: Relativity Theory and Quantum Theory. These two discoveries led to continued advancement in physics and the search for understanding the reality of the physical world, when many physicists believed there was nothing else to be accomplished in their discipline.

Let me state this question another way. What does it mean that Relativity Theory and Quantum Theory are not consistent mathematically, but display anunbroken wholenessin their concepts?

Bohm was seeking some way forward where the mathematical apparatus would apply to both theories without contradictions in their concepts. What Bohm found was that relativity theory and quantum theory have the quality ofunbroken wholenessin common, although it is achieved in a different way, but theorized it may be a way forward.

First, lets consider how wholeness is achieved in relativity theory. Simply put, the basic idea is that a point in spacetime is called an event, which is totally distinct from all other point events. So, all structures may be seen as configurations in a universal field, which is a function of all the space-time points. Therefore, the field is continuous and inseparable. A particle (physical object) in the field has to be treated as a singularity or stable pulse of finite extent. The field around the stable pulse lessens in intensity with increasing distance from it, but it does not shrink to zero. As a result, allthe fields for the stable pulses merge to form a single structure, of unbroken wholeness. A singularity in space-time is non-mechanistic construct, which is independent of the Cartesian grid system.

Next, consider how wholeness is exhibited in Bohms interpretation of quantum theory. It is achieved throughactive informationlisted as a concept represented by the quantum potential. The quantum potential is the microstructure for transmitting influences on distance parts of the correlated quantum system through nonlocal connections. It basically interconnects all distant objects of the quantum field into a single system, and as Bohm states, with an objective quality ofunbroken wholeness.

In physics, all fields are defined by space-time points put in order and understood using the Cartesian co-ordinate grid. And, if necessary, they are extended to curvilinear coordinates. But it is a mechanistic order, whose parts have and independent existence in different regions of space and time. So, it has been and continues to be inadequate for ordering the unbroken wholeness and contradictions of quantum theory and relativity theory. Such a situation calls for seeking a different order that will allow both theories to be consistent conceptually, and potentially pave the way for further advancements to these theories. Bohm has suggested theImplicate Order,but this would be a discussion for another interview or paper.

CP.3. How do I, Carl Peterson, think a scientist should include consciousness? First let me emphasize:I am a Bohmian, no doubt. And work by Bohm on An Ontological Interpretation of Quantum Theory (Bohm D. a., 1994) has shown there is a consistent and empirically adequate deterministic theory available.

In that regard, it would be fruitless to try to account for consciousness within the Cartesian coordinate grid system. In fact, any research in which the Cartesian coordinate grid system is used would not cohere with consciousness. Why? Because it is mechanistic.

However, paradoxically, it takes a conscious mind to be aware, to think, and do critical work in physics. This becomes clearer in quantum theory. Even so, consciousness doesnt appear in the equations.

Again, being a Bohmian I will follow his lead. It is Bohms proposal that the implicate order is where quantum theory and consciousness become compatible. And I agree with his proposal.

What is the implicate order you ask? My answer is: implicate order theory takes what quantum theory and relativity theory have in common, wholeness, and works naturally with their contradictions, which come from using the Cartesian grid, through the mental, physical and sensory awareness that embraces consciousness.

The theory is limited! No physical theory gives a perfect replica of reality, since a theory is part of the thought process. And the thought process is limited by information humans receive and their memory for retention of that information.

CP.4. You ask me about QM-NIODA. How might it change if the Bohmian interpretation was adopted rather than the Copenhagen interpretation?

Let me state emphatically that Bohmian determinism is compatible with QM-NIODA ontological indeterminism, and the measurement problem doesnt exist with Bohms interpretation. And, the quantum potential presents new concepts that have to be considered since they dont exist in the Copenhagen interpretation.

So, it seems to me that changes would come about because much of the activity that occurs in the microworld happens because of the quantum potential in Bohms interpretation. But Russell labels these thorny issues. Setting that statement aside, there are two types of changes that seem necessary to locate the physics for NIODA to cohere with the Bohmian interpretation. Number one leads to number two. I briefly discussed some features of number two earlier. The two types are:

1) new developments in physics always require attention to language. This is necessary to communicate the perception and thinking about the new development. Therefore, language would be the first type of change in NIODA.

2) different factors underlie the different language. Specifically, Russells NIODA needs to account for quantum potential as Bohmn articualtes it. Bohms visionary insight of recognizing the quantum potential, since activity is taking place in the quantum world because of it. Therefore, the features brought in by the quantum potential are most important as well with the different language. I mentioned four earlier. I see those as most crucial. Lets set the stage!

The mathematical form of the wavefunction sets the quantum field. And then, nonlocality locates Divine Action in the quantum world, since it is completely the product of the quantum potential. Recall from earlier question that the quantum potential doesnt exist in the classical limit, therefore nonlocality doesnt exist there either. Enter active information, which is produced in the quantum field, allowing influences on remote parts of the quantum system to respond in a correlated manner. Moreover, the quantum potential interconnects every region of space and imparts a quality of inseparable wholeness. In other words, the wavefunction for the quantum system determines the nonlocal connections on its distant parts.

CP.5. Yes. A way forward in physics from this point starts by setting aside the Cartesian coordinate grid system. I dont believe the contradictions between relativity and quantum theories can be completely overcome within this grid system. Let me quote something I said recently in our ETI: Academic and Societal Implicationsbook.

Bohm found a way, and that way is a new order, which encompasses the different kinds of unbroken wholeness in both quantum and relativity theories. And that new order, beyond the order of the everyday sensory world in which experiments are carried out, is one that can provide a clear consistent and logical connection for all our concepts; that is mathematical and physical. It is a deeper submerged order for the creative understanding of underlying concepts, and perhaps, even unseen levels of reality.

I might add: this may not be complete answer. But it is a beginning. It points a way forward. Sadly, there are a too few physicists following this route.

Do Patheos bloggers take up quantum theology? Sometimes.

But, not every Patheos blogger is happy with quantum theology. Especially Will Duquette. Duquette modestly formulates his own laws. Heres one thats relevant: Every application of quantum mechanics to philosophy or religion is absurd. Absurd? Why? Duquette says that a theologian is too ignorant to rightly weigh the import of physics. He contends, further, that a physicist is too smart to dabble in theology. What about a hybrid physicist-theologian such as Ian Barbour, John Polkinghorne or Robert John Russell? Duquette says, contrary to the testimony weve just assembled: if the speaker is both a quantum physicist and a philosopher/theologianhell be too wise to apply quantum mechanics to philosophy or theology. This makes Duquettes reasoning more absurd than his law.

What motivates our discussion here on divine action in natures world is the obligation to construct a reasonable and intelligible worldview that explains Gods providential yet non-interventionist action. Quantum theory entices the theologian like a yummy ice cream cone on a hot sunny day.

But, one step at a time. Before the quantum theologian can deal directly with divine action in natures world, the question of the relationship between objective fact and subjective consciousness must be resolved. Henry Stapp, physicist at the University of California at Berkeley, has worked on this question for decades.

Quantum mechanicsassigns to mental reality a function not performed by the physical properties, namely, the property of providing an avenue for our human values to enter into the evolution of psycho-physical reality, and hence make our lives meaningful(Stapp, 2017).

What we see most forcefully in the quantum ontology of David Bohm is a grounding for both consciousness and what consciousness knows in a single holomovement. This QM ontology attracts Carl Peterson.

This should attract Robert John Russell as well. Bohms notion of undivided wholeness in a single holomovement provides an inclusive ontology that coheres with quantum theory and adds a level of wholeness to Russells QM-NIODA.

In conclusion, Robert John Russell need not choose between the indeterminism of Copenhagen and the determinism of Bohm. His quantum theology could benefit from both.

Ted Peters directs traffic at the intersection of science, religion, and ethics. Peters is an emeritus professor at the Graduate Theological Union, where he co-edits the journal, Theology and Science, on behalf of the Center for Theology and the Natural Sciences, in Berkeley, California, USA. He authored Playing God? Genetic Determinism and Human Freedom? (Routledge, 2nd ed., 2002) as well as Science, Theology, and Ethics (Ashgate 2003). Along with Martinez Hewlett, Joshua Moritz, and Robert John Russell, he co-edited, Astrotheology: Science and Theology Meet Extraterrestrial Intelligence (2018). Along with Octavio Chon Torres, Joseph Seckbach, and Russell Gordon, he co-edited, Astrobiology: Science, Ethics, and Public Policy (Scrivener 2021). He is also author of UFOs: Gods Chariots? Spirituality, Ancient Aliens, and Religious Yearnings in the Age of Extraterrestrials (Career Press New Page Books, 2014). See his website: TedsTimelyTake.com.

Atkins, P. (2006). Atheism and Science. In e. Philip Clayton and Zachary Simpson, The Oxford Handbook of Religion and Science (pp. 124-136). Oxford UK: Oxford University Press.

Bohm, D. (1951). Quantum Theory. New York: Prentice Hall.

Bohm, D. (1952). A Suggested Interpretation of the Quantum Theory in Terms of Hiddon Variables I and II. Physical Review 85, 166-193.

Bohm, D. (1980). Wholeness and the Implicate Order. London: Routledge.

Bohm, D. (1988). Postmodern Science and a Postmodern World. In e. David Ray Griffin, The Reenchantment of Science (pp. 57-68). Albany NY: SUNY.

Bohm, D. (1990). A New Theory of the Relationship of Mind and Matter. Philosophical Psychology, 3(2), 271-286.

Bohm, D. a. (1994). The Undivided Universe: An Ontological Interpretation of Quantum theory. New Brunswick NJ: Rutgers University Press.

OMurchu, D. (2021). Quantum Theology: Spiritual Implications of the New Physics. New York: Crossroad.

Polkinghorne, J. (2006). Quantum Theology. In e. Ted Peters and Nathan Hallanger, Gods Action in Natures World: Essays in Honor of Robert John Russell (pp. 137-145). Aldershot UK: Ashgate.

Russell, R. J. (1985). The Physics of David Bohm and Its Relevance to Philosophy and Theology. Zygon 20:2, 135-158.

Russell, R. J. (2008). Cosmology from Alpha to Omega: The Creative Mutual Interaction of Theology and Science. Minneapolis MN: Fortress Press ISBN 978-0-8006-6273-8.

Stapp, H. P. (2017). Quantum Theory and Free Will. Switzerland: Springer.

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Quantum Theory, God, and Carl Peterson | Quantum Theology - Patheos

A Bristol-led team of physicists has found a way to operate mass manufacturable photonic sensors at the quantum limit. This breakthrough paves the way for practical applications such as monitoring greenhouse gases and cancer detection.

Sensors are a constant feature of our everyday lives. Although they often go unperceived, sensors provide critical information essential to modern healthcare, security, and environmental monitoring. Modern cars alone contain over 100 sensors and this number will only increase.

Quantum sensing is poised to revolutionise today's sensors, significantly boosting the performance they can achieve. More precise, faster, and reliable measurements of physical quantities can have a transformative effect on every area of science and technology, including our daily lives.

However, the majority of quantum sensing schemes rely on special entangled or squeezed states of light or matter that are hard to generate and detect. This is a major obstacle to harnessing the full power of quantum-limited sensors and deploying them in real-world scenarios.

In a paper published in Physical Review Letters, a team of physicists at the Universities of Bristol, Bath and Warwick have shown it is possible to perform high precision measurements of important physical properties without the need for sophisticated quantum states of light and detection schemes.

The key to this breakthrough is the use of ring resonators tiny racetrack structures that guide light in a loop and maximize its interaction with the sample under study. Importantly, ring resonators can be mass manufactured using the same processes as the chips in our computers and smartphones.

Alex Belsley, Quantum Engineering Technology Labs (QET Labs) PhD student and lead author of the work, said:We are one step closer to allintegrated photonic sensorsoperating at the limits of detection imposed by quantum mechanics.

Employing this technology to sense absorption or refractive index changes can be used to identify and characterise a wide range of materials and biochemical samples, with topical applications from monitoring greenhouse gases to cancer detection.

Associate Professor Jonathan Matthews, co-Director of QETLabs and co-author of the work, stated: We are really excited by the opportunities this result enables: we now know how to use mass manufacturable processes to engineer chip scale photonic sensors that operate at the quantum limit.

Paper:

'Advantage of coherent states in ring resonators over any quantum probe single-pass absorption estimation strategy,' by Alexandre Belsley, Euan J. Allen, Animesh Datta, and Jonathan C. F. Matthewsis published in Physical Review Letters.

The Quantum Engineering Technology Labs (QET Labs)

QET Labs was launched in 2015, with the mission to take quantum science discoveries out of the lab and engineer them into technologies for the benefit of society. This includes novel routes to quantum computing hardware, quantum communications, enhanced sensing & imaging and new platforms to investigate fundamental quantum physics. QET Labs brings together over 28 million worth of activity and comprises over 100 academics, staff, and students in the Schools of Physics and Electrical and Electronic Engineering. Read more: https://www.bristol.ac.uk/qet-labs/

Bristol's EPSRC-fundedQuantum Engineering Centre for Doctoral Trainingoffers an exceptional training and development experience for those wishing to pursue a career in the emerging quantum technologies industry or in academia. It supports the understanding of sound fundamental scientific principles and their practical application to real-world challenges.

Bristol Quantum Information Institute

Quantum information and its translation into technologies is one of the most exciting research activities in science and technology today. Long at the forefront of the growing worldwide activity in this area, the Bristol Quantum Information Institute crystallises our research across the entire spectrum, from theory to technology. With our expert cross-disciplinary team, including founders of the field, we have expertise in all major areas of theoretical quantum information science and in experiment. We foster partnerships with the private sector and provide superb teaching and training for the future generation of quantum scientists and engineers and the prototypes of tomorrow.

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June: photonic sensors | News and features - University of Bristol

Heres some inside baseball about physics research. High energy theory was a field with vast accomplishments across the 20th century and its success was propelled by a series of physics geniuses who won support and funding for a seven-decade succession of particle colliders. These colliders smashed matter together and discovered particle after particle streaming out of the explosions. The geniuses built the Standard Model to explain the particles. The Large Hadron Collider (LHC), located in Switzerland, was the capstone of their era, finding the last required particle the Higgs boson to complete the model.

Today, those geniuses are nearly all gone and their successors are bogged down in various forms of mathematical supersymmetry. Youve heard of some of its ideas: string theory, M-theory, D-branes, and so forth. Its all fun to read about. But the problem is that it doesnt explain anything. High energy theory has become highly academic and mathematical. Einstein postulated four-dimensional spacetime because he needed four dimensions to make sense of the world as we see it. String theory requires 11 dimensions or maybe 10, or 12, or 26. Maybe some are curled up. Why? Because neat things happen in abstract math, apparently.

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Supersymmetry is not a tight and efficient theory, welded together to explain observations. Its a convoluted mess of mathematical models that could potentially explain anything, or nothing at all. Sabine Hossenfelder, a theoretical physicist who has worked in the field, gives an excellent review of the situation. She doesnt pull punches. A giant particle collider cannot truly test supersymmetry, which can evolve to fit nearly anything.

This brings us to the LHC, and its hypothetical successor, call it LHC++. The LHC found the Higgs. However, it has had nothing to say about supersymmetry or string theory. Sabine points out that no LHC result could ever rule out supersymmetry. Whats worse, the LHC++ could not rule it out either. The only hope for an enormous new collider would be to happen upon a new and unexpected particle.

Its not a terrible idea, in a vacuum. Science occasionally progresses when scientists stumble across some entirely new and unexpected phenomena. Ethan Siegel makes the case for building LHC++ for this reason. He believes that arguments against it are disingenuous, or made in bad faith. However, hes wrong on this one. Economic and scientific sense argue for a different approach.

A significantly more powerful LHC++ will cost tens of billions of dollars. Its entirely possible that the price could swell to $100 billion. Spending that much money on a machine to take shots in the dark is a mistake. When you dont have much to go on, and limited resources, its better to aim at problems that you know are out there. Those things will lead you to new discoveries. The revolutionary success of 20th-century physics was kicked off in just this way.

Many leading scientists of the late 1800s speculated that physics was nearly finished. There remained only a few mysteries. Two of these known mysteries were the nature of blackbody radiation and the constant speed of light. Both phenomena were studied and measured, but could not be explained. Einstein and others focused on finding solutions to these outstanding problems. The answers lead directly to the development of quantum mechanics and relativity: two of the cornerstone theories of modern physics.

There are many known problems in physics right now. $100 billion could fund (quite literally) 100,000 smaller physics experiments. There may not be enough physics labs on Earth to carry out that many experiments! Ethan points out that we push frontiers such as trillionths-of-a-degree temperatures in new experiments. Thats a great pursuit: It can be done by a handful of researchers, using just a tiny fraction of the funding freed up by not building LHC++. Some of the 100,000 experiments could look for possible physics beyond the Standard Model in clever ways that dont require the annual GDP of a small nation.

Conversely, that $100 billion could be lumped together and spent on one giant project to solve a known real-world problem. Perhaps we should send the money and associated technical talent to solve fusion energy. ITER, the worlds most promising fusion machine, is a colossal (and over-budget) experiment. And still, $100 billion could fund somewhere between one and five more ITERs. Or, it could power hundreds of alternative efforts to create practical fusion energy.

The money and brainpower that would go into a bigger LHC could be much better used to chase one, a few, or many known scientific and practical problems in the world. Along the way, new and unknown physics would certainly turn up, as it always does when you attack previously unsolvable problems. The only good argument for the LHC++ might be employment for smart people. And for string theorists. It just doesnt add up.

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Please, don't build another Large Hadron Collider. - Big Think

Quantum science emerged from studies of the smallest objects in nature. Today, it promises to deepen our understanding of the universe and deliver groundbreaking technology, from quantum computers to ultra-precise measuring devices to next-generation materials, with many of these advances happening at Caltech. In Conversations on the Quantum World, you will hear directly from Caltech experts about the next quantum revolution and have the opportunity to ask your own questions.

Zoom in on a digital image far enough and you will discover the distinct pixels that make the picture. Could the universe itself be similarly pixelated? Theoretical physicist Kathryn Zurek and experimental physicist Rana Adhikari are on the hunt for this pixelation, a signature of what is known as quantum gravity, a set of theories that attempts to unite the microscopic world of quantum physics with the macroscopic world of gravity. In this event, they will speak with science writer Whitney Clavin about how they use innovative instrumentation and approaches to try to solve the mystery of quantum gravity.

This is a free event, but registration is required. The first 1,000 attendees can join the Zoom webinar. Others will be provided with a YouTube link.

This series is presented by the Caltech Science Exchange, which brings expert insight to the scientific questions that define our time. The Science Exchange offers trustworthy answers, clear explanations, and fact-driven conversation on critical topics in science and technology.

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Conversations on the Quantum World: Why Space Isn't What You Think It Is - Caltech

Classical physics did not need any disclaimers. The kind of physics that was born with Isaac Newton and ruled until the early 1900s seemed pretty straightforward: Matter was like little billiard balls. It accelerated or decelerated when exposed to forces. None of this needed any special interpretations attached. The details could get messy, but there was nothing weird about it.

Then came quantum mechanics, and everything got weird really fast.

Quantum mechanics is the physics of atomic-scale phenomena, and it is the most successful theory we have ever developed. So why are there a thousand competing interpretations of the theory? Why does quantum mechanics need an interpretation at all?

What, fundamentally, is it trying to tell us?

There are many weirdnesses in quantum physics many ways it differs from the classical worldview of perfectly knowable particles with perfectly describable properties. The weirdness you focus on will tend to be the one that shapes your favorite interpretation.

But the weirdness that has stood out most, the one that has shaped the most interpretations, is the nature of superpositions and of measurement in quantum mechanics.

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Everything in physics comes down to the description of what we call the state. In classical physics, the state of a particle was just its position and momentum. (Momentum is related to velocity.) The position and velocity could be known with as much accuracy as your equipment allowed. Most important, the state was never connected to making a measurement you never had to look at the particle. But quantum mechanics forces us to think about the state in a very different way.

In quantum physics, the state represents the possible outcomes of measurements. Imagine you have a particle in a box, and the box has two accessible chambers. Before a measurement is made, the quantum state is in a superposition, with one term for the particle being in the first chamber and another term for the particle being in the second chamber. Both terms exist at the same time in the quantum state. It is only after a measurement is made that the superposition is said to collapse, and the state has only one term the one that corresponds to seeing the particle in the first or the second chamber.

So, what is going on here? How can a particle be in two places at the same time? This is also akin to asking whether particles have properties in and of themselves. Why should making a measurement change anything? And what exactly is a measurement? Do you need a person to make a measurement, or can you say that any interaction at all with the rest of the world is a measurement?

These kinds of questions have spawned a librarys worth of so-called quantum interpretations. Some of them try to preserve the classical worldview by finding some way to minimize the role of measurement and preserve the reality of the quantum state. Here, reality means that the state describes the world by itself, without any reference to us. At the extreme end of these is the Many Worlds Interpretation, which makes each possibility in the quantum state a parallel Universe that will be realized when a quantum event a measurement happens.

This kind of interpretation is, to me, a mistake. My reasons for saying this are simple.

When the inventors of quantum mechanics broke with classical physics in the first few decades of the 1900s, they were doing what creative physicists do best. They were finding new ways to predict the results of experiments by creatively building off the old physics while extending it in ways that embraced new behaviors seen in the laboratory. That took them in a direction where measurement began to play a central role in the description of physics as a whole.Again and again, quantum mechanics has shown that at the heart of its many weirdnesses is the role played by someone acting on the world to gain information. That to me is the central lesson quantum mechanics has been trying to teach us: That we are involved, in some way, in the description of the science we do.

Now to be clear, I am not arguing that the observer affects the observed, or that physics needs a place for some kind of Cosmic Mind, or that consciousness reaches into the apparatus and changes things. There are much more subtle and interesting ways of hearing what quantum mechanics is trying to say to us. This is one reason I find much to like in the interpretation called QBism.

What matters is trying to see into the heart of the issue. After all, when all is said and done, what is quantum mechanics pointing to? The answer is that it points to us. It is trying to tell us what it means to be a subject embedded in the Universe, doing this amazing thing called science. To me that is just as exciting as a story about a Gods eye view of the Universe.

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What is quantum mechanics trying to tell us? - Big Think

There are some questions that, if you look up the answer, might make you question the reliability of your brain.

Many other examples abound, from the color of different flavor packets of Walkers crisps to the spelling of Looney Tunes (vs. Looney Toons) and Febreze (vs. Febreeze) to whether the Monopoly Man has a monocle or not.

Perhaps the simplest explanation for all of these is simply that human memory is unreliable, and that as much as we trust our brains to remember what happened in our own lives, our own minds are at fault. But theres another possibility based on quantum physics thats worth considering: could these truly have been the outcomes that occurred for us, but in a parallel Universe? Heres what the science has to say.

Visualization of a quantum field theory calculation showing virtual particles in the quantum vacuum. (Specifically, for the strong interactions.) Even in empty space, this vacuum energy is non-zero, and what appears to be the ground state in one region of curved space will look different from the perspective of an observer where the spatial curvature differs. As long as quantum fields are present, this vacuum energy (or a cosmological constant) must be present, too.

One of the biggest differences between the classical world and the quantum world is the notion of determinism. In the classical world which also defined all of physics, including mechanics, gravitation, and electromagnetism prior to the late 19th century the equations that govern the laws of nature are all completely deterministic. If you can give details about all of the particles in the Universe at any given moment in time, including their mass, charge, position, and momentum at that particular moment, then the equations that govern physics can tell you both where they were and where they will be at any moment in the past or future.

But in the quantum Universe, this simply isnt the case. No matter how accurately you measure certain properties of the Universe, theres a fundamental uncertainty that prevents you from knowing those properties arbitrarily well at the same time. In fact, the better you measure some of the properties that a particle or system of particles can have, the greater the inherent uncertainty becomes an uncertainty that you can not get rid of or reduce below a critical value in other properties. This fundamental relation, known as the Heisenberg uncertainty principle, cannot be worked around.

This diagram illustrates the inherent uncertainty relation between position and momentum. When one is known more accurately, the other is inherently less able to be known accurately. Every time you accurately measure one, you ensure a greater uncertainty in the corresponding complementary quantity.

Travel the Universe with astrophysicist Ethan Siegel. Subscribers will get the newsletter every Saturday. All aboard!

There are many other examples of uncertainty in quantum physics, and many of those uncertain measurements dont just have two possible outcomes, but a continuous spectrum of possibilities. Its only by measuring the Universe, or by causing an interaction of an inherently uncertain system with another quantum from the environment, that we discover which of the possible outcomes describes our reality.

The Many Worlds Interpretation of quantum mechanics holds that there are an infinite number of parallel Universes that exist, holding all possible outcomes of a quantum mechanical system, and that making an observation simply chooses one path. This interpretation is philosophically interesting, but may add nothing-of-value when it comes to actual physics.

One of the problems with quantum mechanics is the problem of, What does it mean for whats really going on in our Universe? We have this notion that there is some sort of objective reality a really real reality thats independent of any observer or external influence. That, in some way, the Universe exists as it does without regard for whether anyone or anything is watching or interacting with it.

This very notion is not something were certain is valid. Although its pretty much hard-wired into our brains and our intuitions, reality is under no obligation to conform to them.

What does that mean, then, when it comes to the question of whats truly going on when, for example, we perform the double-slit experiment? If you have two slits in a screen that are narrowly spaced, and you shine a light through it, the illuminated pattern that shows up behind the screen is an interference pattern: with multiple bright lines patterned after the shape of the slit, interspersed with dark lines between them. This is not what youd expect if you threw a series of tiny pebbles through that double slit; youd simply expect two piles of rocks, with each one corresponding to the rocks having gone through one slit or the other.

Results of a double-slit-experiment performed by Dr. Tonomura showing the build-up of an interference pattern of single electrons. If the path of which slit each electron passes through is measured, the interference pattern is destroyed, leading to two piles instead. The number of electrons in each panel are 11 (a), 200 (b), 6000 (c), 40000 (d), and 140000 (e).

The thing about this double slit experiment is this: as long as you dont measure which slit the light goes through, you will always get an interference pattern.

This remains true even if you send the light through one photon at a time, so that multiple photons arent interfering with one another. Somehow, its as though each individual photon is interfering with itself.

Its still true even if you replace the photon with an electron, or other massive quantum particles, whether fundamental or composite. Sending electrons through a double slit, even one at a time, gives you this interference pattern.

And it ceases to be true, immediately and completely, if you start measuring which slit each photon (or particle) went through.

But why? Why is this the case?

Thats one of the puzzles of quantum mechanics: it seems as though its open to interpretation. Is there an inherently uncertain distribution of possible outcomes, and does the act of measuring simply pick out which outcome it is that has occurred in this Universe?

Is it the case that everything is wave-like and uncertain, right up until the moment that a measurement is made, and that act of measuring a critical action that causes the quantum mechanical wavefunction to collapse?

When a quantum particle approaches a barrier, it will most frequently interact with it. But there is a finite probability of not only reflecting off of the barrier, but tunneling through it. The actual evolution of the particle is only determined by measurement and observation, and the wavefunction interpretation only applies to the unmeasured system; once its trajectory has been determined, the past is entirely classical in its behavior.

Or is it the case that each and every possible outcome that could occur actually does occur, but simply not in our Universe? Is it possible that there are an infinite number of parallel Universes out there, and that all possible outcomes occur infinitely many times in a variety of them, but it takes the act of measurement to know which one occurred in ours?

Although these might all seem like radically different possibilities, theyre all consistent (and not, by any means, an exhaustive list of) interpretations of quantum mechanics. At this point in time, the only differences between the Universe they describe are philosophical. From a physical point of view, they all predict the same exact results for any experiment we know how to perform at present.

However, if there are an infinite number of parallel Universes out there and not simply in a mathematical sense, but in a physically real one there needs to be a place for them to live. We need enough Universe to hold all of these possibilities, and to allow there to be somewhere within it where every possible outcome can be real. The only way this could work is if:

From a pre-existing state, inflation predicts that a series of universes will be spawned as inflation continues, with each one being completely disconnected from every other one, separated by more inflating space. One of these bubbles, where inflation ended, gave birth to our Universe some 13.8 billion years ago, where our entire visible Universe is just a tiny portion of that bubbles volume. Each individual bubble is disconnected from all of the others.

The Universe needs to be born infinite because the number of possible outcomes that can occur in a Universe that starts off like ours, 13.8 billion years ago, increases more quickly than the number of independent Universes that come to exist in even an eternally inflating Universe. Unless the Universe was born infinite in size a finite amount of time ago, or it was born finite in size an infinite amount of time ago, its simply not possible to have enough Universes to hold all possible outcomes.

But if the Universe was born infinite and cosmic inflation occurred, suddenly the Multiverse includes an infinite number of independent Universes that start with initial conditions identical to our own. In such a case, anything that could occur not only does occur, but occurs an infinite number of times. There would be an infinite number of copies of you, and me, and Earth, and the Milky Way, etc., that exist in an infinite number of independent Universe. And in some of them, reality unfolds identically to how it did here, right up until the moment when one particular quantum measurement takes place. For us in our Universe, it turned out one way; for the version of us in a parallel Universe, perhaps that outcome is the only difference in all of our cosmic histories.

The inherent width, or half the width of the peak in the above image when youre halfway to the crest of the peak, is measured to be 2.5 GeV: an inherent uncertainty of about +/- 3% of the total mass. The mass of the particle in question, the Z boson, is peaked at 91.187 GeV, but that mass is inherently uncertain by a significant amount.

But when we talk about uncertainty in quantum physics, were generally talking about an outcome whose results havent been measured or decided just yet. Whats uncertain in our Universe isnt past events that have already been determined, but only events whose possible outcomes have not yet been constrained by measurables.

If we think about a double slit experiment thats already occurred, once weve seen the interference pattern, its not possible to state whether a particular electron traveled through slit #1 or slit #2 in the past. That was a measurement we could have made but didnt, and the act of not making that measurement resulted in the interference pattern appearing, rather than simply two piles of electrons.

There is no Universe where the electron travels either through slit #1 or slit #2 and still makes an interference pattern by interfering with itself. Either the electron travels through both slits at once, allowing it to interfere with itself, and lands on the screen in such a way that thousands upon thousands of such electrons will expose the interference pattern, or some measurements occurs to force the electron to solely travel through slit #1 or slit #2 and no interference pattern is recovered.

Perhaps the spookiest of all quantum experiments is the double-slit experiment. When a particle passes through the double slit, it will land in a region whose probabilities are defined by an interference pattern. With many such observations plotted together, the interference pattern can be seen if the experiment is performed properly; if you retroactively ask which slit did each particle go through? you will find youre asking an ill-posed question.

What does this mean?

It means as was recognized by Heisenberg himself nearly a century ago that the wavefunction description of the Universe does not apply to the past. Right now, there are a great many things that are uncertain in the Universe, and thats because the critical measurement or interaction to determine what that things quantum state is has not yet been taken.

In other words, there is a boundary between the classical and quantum the definitive and the indeterminate and the boundary between them is when things become real, and when the past becomes fixed. That boundary, according to physicist Lee Smolin, is what defines now in a physical sense: the moment where the things that were observing at this instant fixes certain observables to have definitively occurred in our past.

We can think about infinite parallel Universes as opening up before us as far as future possibilities go, in some sort of infinitely forward-branching tree of options, but this line of reasoning does not apply to the past. As far as the past goes, at least in our Universe, previously determined events have already been metaphorically written in stone.

This 1993 photo by Carol M. Highsmith shows the last president of apartheid-era South Africa, F.W. de Klerk, alongside president-elect Nelson Mandela, as both were about to receive Americas Liberty Medal for effecting the transition of power away from white minority rule and towards universal majority rule. This event definitively occurred in our Universe.

In a quantum mechanical sense, this boils down to two fundamental questions.

The answer seems to be no and no. To achieve a macroscopic difference from quantum mechanical outcomes means weve already crossed into the classical realm, and that means the past history is already determined to be different. There is no way back to a present where Nelson Mandela dies in 2013 if he already died in prison in the 1980s.

Furthermore, the only places where these parallel Universes can exist is beyond the limit of our observable Universe, where theyre completely causally disconnected from anything that happens here. Even if theres a quantum mechanical entanglement between the two, the only way information can be transferred between those Universes is limited by the speed of light. Any information about what occurred over there simply doesnt exist in our Universe.

We can imagine a very large number of possible outcomes that could have resulted from the conditions our Universe was born with, and a very large number of possible outcomes that could have occurred over our cosmic history as particles interact and time passes. If there were enough possible Universes out there, it would also be possible that the same set of outcomes happened in multiple places, leading to the scenario of infinite parallel Universes. Unfortunately, we only have the one Universe we inhabit to observe, and other Universes, even if they exist, are not causally connected to our own.

The truth is that there may well be parallel Universes out there in which all of these things did occur. Maybe there is a Berenstein Bears out there, along with Shazaam the movie and a Nelson Mandela who died in prison in the 1980s. But that has no bearing on our Universe; they never occurred here and no one who remembers otherwise is correct. Although the neuroscience of human memory is not fully understood, the physical science of quantum mechanics is well-enough understood that we know whats possible and what isnt. You do have a faulty memory, and parallel Universes arent the reason why.

Excerpt from:

Could quantum mechanics explain the Mandela effect? - Big Think

Today lets take a walk on the wild side and assume, for the sake of argument, that our Universe is not the only one that exists. Lets consider that there are many other universes, possibly infinitely many. The totality of these universes, including our own, is what cosmologists call the Multiverse. It sounds more like a myth than a scientific hypothesis, and this conceptual troublemaker inspires some while it outrages others.

The controversy started in the 1980s. Two physicists, Andrei Linde at Stanford University and Alex Vilenkin at Tufts University, independently proposed that if the Universe underwent a very fast expansion early on in its existence we call this an inflationary expansion then our Universe would not be the only one.

This inflationary phase of growth presumably happened a trillionth of a trillionth of a trillionth of one second after the beginning of time. That is about 10-36 seconds after the bang when the clock that describes the expansion of our universe started ticking. You may ask, How come these scientists feel comfortable talking about times so ridiculously small? Wasnt the Universe also ridiculously dense at those times?

Well, the truth is we do not yet have a theory that describes physics under these conditions. What we do have are extrapolations based on what we know today. This is not ideal, but given our lack of experimental data, it is the only place we can start from. Without data, we need to push our theories as far as we consider reasonable. Of course, what is reasonable for some theorists will not be for others. And this is where things get interesting.

The supposition here is that we can apply essentially the same physics at energies that are about one thousand trillion times higher than the ones we can probe at the Large Hadron Collider, the giant accelerator housed at the European Organization for Nuclear Research in Switzerland. And even if we cannot apply quite the same physics, we can at least apply physics with similar actors.

In high energy physics, all the characters are fields. Fields, here, mean disturbances that fill space and may or may not change in time. A crude picture of a field is that of water filling a pond. The water is everywhere in the pond, with certain properties that take on values at every point: temperature, pressure, and salinity, for example. Fields have excitations that we call particles. The electron field has the electron as an excitation. The Higgs field has the Higgs boson. In this simple picture, we could visualize the particles as ripples of water propagating along the surface of the pond. This is not a perfect image, but it helps the imagination.

The most popular protagonist driving inflationary expansion is a scalar field an entity with properties inspired by the Higgs boson, which was discovered at the Large Hadron Collider in July 2012.

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We do not know if there were scalar fields at the cosmic infancy, but it is reasonable to suppose there were. Without them, we would be horribly stuck trying to picture what happened. As mentioned above, when we do not have data, the best that we can do is to build reasonable hypotheses that future experiments will hopefully test.

To see how we use a scalar field to model inflation, picture a ball rolling downhill. As long as the ball is at a height above the bottom of the hill, it will roll down. It has stored energy. At the bottom, we set its energy to zero. We do the same with the scalar field. As long as it is displaced from its minimum, it will fill the Universe with its energy. In large enough regions, this energy prompts the fast expansion of space that is the signature of inflation.

Linde and Vilenkin added quantum physics to this picture. In the world of the quantum, everything is jittery; everything vibrates endlessly. This is at the root of quantum uncertainty, a notion that defies common sense. So as the field is rolling downhill, it is also experiencing these quantum jumps, which can kick it further down or further up. Its as if the waves in the pond were erratically creating crests and valleys. Choppy waters, these quantum fields.

Here comes the twist: When a sufficiently large region of space is filled with the field of a certain energy, it will expand at a rate related to that energy. Think of the temperature of the water in the pond. Different regions of space will have the field at different heights, just as different regions of the pond could have water at different temperatures. The result for cosmology is a plethora of madly inflating regions of space, each expanding at its own rate. Very quickly, the Universe would consist of myriad inflating regions that grow, unaware of their surroundings. The Universe morphs into a Multiverse.Even within each region, quantum fluctuations may drive a sub-region to inflate. The picture, then, is one of an eternally replicating cosmos, filled with bubbles within bubbles. Ours would be but one of them a single bubble in a frothing Multiverse.

This is wildly inspiring. But is it science? To be scientific, a hypothesis needs to be testable. Can you test the Multiverse? The answer, in a strict sense, is no. Each of these inflating regions or contracting ones, as there could also be failed universes is outside our cosmic horizon, the region that delimits how far light has traveled since the beginning of time. As such, we cannot see these cosmoids, nor receive any signals from them. The best that we can hope for is to find a sign that one of our neighboring universes bruised our own space in the past. If this had happened, we would see some specific patterns in the sky more precisely, in the radiation left over after hydrogen atoms formed some 400,000 years after the Big Bang. So far, no such signal has been found. The chances of finding one are, quite frankly, remote.

We are thus stuck with a plausible scientific idea that seems untestable. Even if we were to find evidence for inflation, that would not necessarily support the inflationary Multiverse. What are we to do?

The Multiverse suggests another ingredient the possibility that physics is different in different universes. Things get pretty nebulous here, because there are two kinds of different to describe. The first is different values for the constants of nature (such as the electron charge or the strength of gravity), while the second raises the possibility that there are different laws of nature altogether.

In order to harbor life as we know it, our Universe has to obey a series of very strict requirements. Small deviations are not tolerated in the values of natures constants. But the Multiverse brings forth the question of naturalness, or of how common our Universe and its laws are among the myriad universes belonging to the Multiverse. Are we the exception, or do we follow the rule?

The problem is that we have no way to tell. To know whether we are common, we need to know something about the other universes and the kinds of physics they have. But we dont. Nor do we know how many universes there are, and this makes it very hard to estimate how common we are. To make things worse, if there are infinitely many cosmoids, we cannot say anything at all. Inductive thinking is useless here. Infinity gets us tangled up in knots. When everything is possible, nothing stands out, and nothing is learned.

That is why some physicists worry about the Multiverse to the point of loathing it. There is nothing more important to science than its ability to prove ideas wrong. If we lose that, we undermine the very structure of the scientific method.

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How the Multiverse could break the scientific method - Big Think