Oxford Questions seek to pull back the curtain on the foundations of quantum physics

July 18, 2013 by Lisa Zyga, Phys.org feature

The Oxford Questions were developed by theorists, experimentalists, and philosophers of physics in order to elucidate the areas of physics in which genuine progress may be made in the foreseeable future. Credit: G. A. D. Briggs, et al.
(Phys.org) —Relativity and quantum theory form the backbone of modern physics, but a group of physicists stresses that daily use of these theories can numb the sense of wonder at their immense empirical success. At the same time, fundamental questions on the foundations of these two theories remain. In 2010, experimentalists, theorists, and philosophers of physics convened at a conference at the University of Oxford called Quantum Physics and the Nature of Reality. They produced a set of "Oxford Questions" aimed at identifying some specific open problems about the nature of quantum reality in order to stimulate and guide future research.

The Oxford Questions are presented in a new Perspective Paper published by physicists G. A. D. Briggs at the University of Oxford, J. N. Butterfield at the University of Cambridge, and A. Zeilinger at the University of Vienna in a recent issue of Proceedings of the Royal Society A.

At the conference, the scientists emphasized that they wanted to "avoid rehashing various aspects of the status quo in debates about the foundations of ." Instead, their set of questions focuses on issues that can be specifically investigated with current methods and theories. The five broad categories of questions are (1) time, irreversibility, entropy, and information; (2) the quantum-classical relationships; (3) experiments to probe the foundations of quantum physics; (4) quantum physics in the landscape of theories; and (5) interactions with questions in philosophy. (See accompanying figure for details.)

"The Oxford Questions seek to take problems which would be widely recognized by the academic community, and to articulate topics on which there is a prospect of making in the foreseeable future," Briggs told Phys.org. "In this way, we hope that the Oxford Questions will provide an agenda for successful research by philosophers, theorists, and experimentalists. Some of this will require the expertise of more than one discipline. The Oxford Questions include issues on which there is currently a divergence of views even among experts."

Taking a broader perspective, the physicists explain that the Oxford Questions can be thought of as addressing two larger "clouds" on the horizon that may threaten the success of 20th century physics, just like the anomalies confronting classical physics did at the end of the 19th century.

The first cloud is the quantum measurement problem: "the difficulty of explaining completely, in terms of , the emergence of a classical world, i.e., a world so accurately described by classical physics with its definite values—a world free of superposition and entanglement." The scientists call this cloud "the cat in the room," and explain how several of the Oxford Questions probe the measurement problem more deeply.

The analogous "elephant in the room" is the search for a quantum theory of gravity, which is the second cloud. The physicists think there are several reasons why reconciling general relativity and quantum theory is so elusive. One reason is that, whereas relativity theory is grounded on reasonable physical principles, it's unclear whether quantum theory is based on comparable principles. Another reason is the dire lack of experimental data. Testable characteristics of quantum gravity arise only under conditions of such high energy, short distances, and short times that they are inaccessible to researchers. For example, the physicists note that the Planck length (10-35 m) is as many orders of magnitude from the diameter of a quark (10-18 m) as that diameter is from the familiar scale of a centimeter.

Although these two clouds highlight the problems with quantum physics, the physicists also point out that the Oxford Questions arise in large part from empirical work from the last 100 years that has shown the immense success of the basic postulates of relativity and quantum theory. They give many examples in which these postulates have proven to be successful in domains far beyond their original ones:

"Why should the new chronogeometry, introduced by Einstein's special relativity in 1905 for electromagnetism, be extendible to mechanics, thermodynamics and other fields of physics? And why should the quantum theory devised for systems of atomic dimensions (10?10 m) be good for scales both much smaller (cf. high-energy experiments 10?17 to 10?20 m) and vastly larger (cf. superconductivity and superfluidity, or even a neutron interferometer, involving scales of a fraction of a metre or more)? Is there an upper limit to the scale on which quantum theory should be expected to work? There is a sense in which all properties of matter are quantum mechanical. Topics as diverse as phase changes of alloys and conduction in semiconductors have all yielded to quantum theory. New quantum mechanical models are being developed for a growing range of superconductors, magnets, multiferroics and topological insulators.

"The point applies equally well when we look beyond terrestrial physics. General relativity makes a wonderful story: the theory was created principally by one person, motivated by conceptual, in part genuinely philosophical, considerations—yet, it has proved experimentally accurate in all kinds of astronomical situations. They range from weak gravitational fields such as occur in the solar system, where it famously explains the minuscule precession of the perihelion of Mercury (43" of arc per century) that was unaccounted for by Newtonian theory, to fields 10 000 times stronger in a distant binary pulsar, which in the last 30 years has given us compelling evidence for a phenomenon (gravitational radiation) that was predicted by general relativity and long searched for."

Overall, the aim of the Oxford Questions is to continue expanding these applications and unifying these concepts of quantum physics, just as scientists have been doing for the past several decades.

To describe the present state of physics, the physicists here use an analogy by the theoretical physicist Carlo Rovelli. He compares the present situation in physics to that of the early 17th century when Galileo and Kepler were working on the mechanics of early modern science. Looking back at that time, today's scientists view Galileo's and Kepler's ideas as a mixed bag of insight and error; future scientists may see the ideas of today's brightest researchers in much the same way.

In the meantime, the physicists are using the Oxford Questions to guide their own research. For Briggs, this has led to digging deeper into the philosophical aspects of quantum theory.

"In my own laboratory at Oxford, we benefit from a 'Philosopher in Residence' who is distinguished for his contributions both to physics and to philosophy," Briggs said. "He has already contributed to elucidation of how interpretations of quantum reality can be tested theoretically and experimentally, and he has contributed to the design of practical experiments. We have formulated a new research program entitled 'Experimental Tests of Quantum Reality.' This will address the three topics in the third category of the Oxford Questions. The program has been funded in full and will start on 1 October 2013."

The physicists also plan to follow up on the Oxford Questions as they make progress in searching for answers.

"The grant for 'Experimental Tests of Quantum Reality' will organize a conference in 2014, which will be similar in format to the 2010 conference 'Quantum Physics and the Nature of Reality' at which the Oxford Questions were formulated," Briggs said. "This will provide an opportunity to formulate new questions in the light of progress made. In the following year we shall organize a smaller conference specifically for theologians and church leaders, with the aim of enabling them to benefit from the advances in understanding."

Explore further: Physicists publish solution to the quantum measurement problem

More information: G. A. D. Briggs, et al. "The Oxford Questions on the foundations of quantum physics." Proceedings of The Royal Society A. DOI: 10.1098/rspa.2013.0299 (free)

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5 / 5 (1) Jul 18, 2013
Mystery and wonder,
Joy for the mind and the heart,
A sublime foretaste.
1.5 / 5 (8) Jul 18, 2013
Relativity and quantum theory form the backbone of modern physics, but a group of physicists stresses that daily use of these theories can numb the sense of wonder at their immense empirical success. At the same time, fundamental questions on the foundations of these two theories remain…

Ones who familiar with both theories would found that their weak point is about lacking of philosophic idea behind ; understand their mechanism which could explain how the theories work may help to solve the problem as follow…
3.6 / 5 (5) Jul 18, 2013
If one didn't know this was Templeton funded non-science, the very last sentence gives the game away. Rovelli, loop quantum fringe, and Templeton? They can have each other.

Meanwhile, physics moves on, without contributions from magic and fringe.
2 / 5 (4) Jul 18, 2013
Oxford scholars are intelligently pulling the thinking of the autodidact into the fray, fearful lest the ideas of those who have followed only instruction under the umbrella of academia be taken seriously for peer review. Much of today's teachings are founded on the theories and investigations of savants whose insights were gained largely from self-study. Thousands of "physicists" are graduating every year from universities and colleges. Are all of them to be taken seriously? I'm thinking that they (the Oxford scholars) are thinking that the internet is going to rescue us all. They might be right.
5 / 5 (1) Jul 19, 2013
"In the following year we shall organize a smaller conference specifically for theologians and church leaders, with the aim of enabling them to benefit from the advances in understanding."

I should have started reading this article from the bottom up and would've avoided wasting 5 minutes of my life on such a joke. I'm appalled that this web site, supposedly a disseminator of serious scientific advances would post such laughable garbage. I'll surely remember to stay away from the quantum physics section from now on, since apparently I can get the same news from the CNN Belief blog.
1 / 5 (1) Jul 19, 2013
These questions show a mindview that is so last century. In particular, (2)(c) "How can a single-world realistic interpretation of quantum theory be compatible with non-locality and special relativity?"

The correct answer is that it cannot, get over it. The problem is not non-locality or special relativity, it is the fact that the real world can be seen in a quantum superposition of states. Yes, the experiments to make such non-collapsed states visible at a human level are difficult. But they can be and have been performed. The universe is always evolving from a quantum superposition of states into a new superposition of states. Waving magic wands to make that fundamental truth go away is a waste of time.
5 / 5 (1) Jul 19, 2013
If one didn't know this was Templeton funded non-science, the very last sentence gives the game away. Rovelli, loop quantum fringe, and Templeton? They can have each other.

Meanwhile, physics moves on, without contributions from magic and fringe.

Aw, you don't think it's fun to watch religions scramble to explain how newly discovered (anything 50 years or less) science fit in with their view of the world all along?
5 / 5 (1) Jul 20, 2013
I like seth lloyd's view of the Universe as a Quantum Computer.
5 / 5 (1) Jul 22, 2013
Introduction to the Work of Laurent Nottale
The following reflection is mainly based on Lee Smolin's "The TROUBLE with PHYSICS (2006)".
"The current revolution in physics began in 1900, with Max Planck's discovery of a formula describing the energy distribution in the spectrum of heat radiation, which demonstrated that the energy is not continuous but quantized. This revolution has yet to end. The problems that physicists must solve today are, to a large extent, questions that remain unanswered because of the incompleteness of the twentieth century's scientific revolution. The core of our failure to complete the present scientific revolution consists of five problems, each famously intractable" (p3):
5 / 5 (1) Jul 22, 2013
"Problem 1: Combine general relativity and quantum theory into a single theory that can claim to be the complete theory of nature." (p5)
"Problem 2: Resolve the problems in the foundations of quantum mechanics, either by making sense of the theory as it stands or by inventing a new theory that does make sense." (p8)
"Problem 3: Determine whether or not the various particles and forces can be unified in a theory that explains them all as manifestations of a single, fundamental entity." (p11)
"Problem 4: Explain how the values of the free constants in the standard model of particle physics are chosen in nature." (p13)
"Problem 5: Explain dark matter and dark energy. Or, if they don't exist, determine how and why gravity is modified on large scales. More generally, explain why the constants of the standard model of cosmology, including the dark energy, have the values they do." (p16)
5 / 5 (1) Jul 22, 2013
And one additional, I think is of capital importance:
Problem 6: Make sure a unified theory of physics embraces the evolutionary worldview, i.e. the arrow of time should emerge naturally, giving account of the evolutionary processes shaping the whole

"[What] we need [is] a theory about what makes up space, a background-independent theory, [as general relativity already is. So, the new theory] has to incorporate the successful dynamical and evolving geometry of space." (p239)
"But today, despite our best efforts, what we know for certain about … is no more than what we knew back in the 1970s." (pviii)
"I believe there is something basic we are all missing, some wrong assumption we are all making. If this is so, then we need to isolate the wrong assumption and replace it with a new idea. What could that wrong assumption be? My guess is that it involves two things: the foundations of quantum mechanics and the nature of time." (p256)
5 / 5 (1) Jul 22, 2013
"Perhaps there is something wrong with the way we are going about trying to make a revolution in physics. Are we recognizing and rewarding the right kind of physics, and the right kind of physicist, in order to solve the problem at hand? Its cognitive counterpart is: Are we asking the right questions? The one thing everyone who cares about fundamental physics seems to agree on is that new ideas are needed. … Every physicist I know will agree that probably at least one big idea is missing. How do we find that missing idea? Clearly, someone has to either recognize a wrong assumption we have all been making or ask a new question, so that's the sort of person we need in order to ensure the future of fundamental physics. The organizational issue is then clear: Do we have a system that allows someone capable of ferreting out that wrong assumption or asking that right question into the community of people we support and (equally important) listen to?
5 / 5 (1) Jul 22, 2013
Do we embrace the creative rebels with this rare talent, or do we exclude them?" (p309)

"[The currently incomplete revolution in physics was originated by] reflection on hard conceptual problems. … This [was] … the way that Albert Einstein, Niels Bohr, Werner Heisenberg, Erwin Schrodinger, and the other early-twentieth-century revolutionaries did science. Their work arose from deep thought on the most basic questions surrounding space, time, and matter, and they saw what they did as part of a broader philosophical tradition, in which they were at home." (pxxiii)
5 / 5 (1) Jul 22, 2013
"As Einstein said in a letter to a young physicist who had been thwarted in his attempts to add philosophy to his physics courses:
"I fully agree with you about the significance and educational value of methodology as well as history and philosophy of science. So many people today - and even professional scientists - seem to me like
someone who has seen thousands of trees but has never seen a forest. A knowledge of the historical and philosophical background gives that kind of independence from prejudices of his generation from
which most scientists are suffering. This independence created by philosophical insight is - in my opinion - the mark of distinction between a mere artisan or specialist and a real seeker after truth."" (p310)

If you're convinced the above is sound, have a look to the papers at http://www.luth.o...wnlo.htm and specially to
Jul 22, 2013
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Jul 22, 2013
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Jul 22, 2013
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5 / 5 (1) Jul 23, 2013
@NAT: thx 4 clarifying your position
not rated yet Jul 25, 2013
Don't you want to be a part of nature?

You mean there is a choice?

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