Saturday, 11 June 2016
| 8:30 – 8:55 | Breakfast | |
| 8:55 – 9:00 | Wayne C. Myrvold: Opening remarks |
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| Chair: Wayne Myrvold |
9:00 – 10:15 | Richard Healey: Correlations, probabilities and quantum states |
| 10:15 – 10:20 | Short break | |
| Chair: Stathis Psillos |
10:20 – 11:35 | Robert Spekkens: Leibniz’s principle of the identity of indiscernibles as a foundational principle for quantum theory |
| 11:35 – 13:00 | Lunch | |
| Chair: Markus Müller |
13:00 – 14:15 | Rüdiger Schack: Participatory realism |
| 14:15 – 14:20 | Short break | |
| Chair: Ruth Kastner |
14:20 – 15:35 | Matthew Pusey: Is QBism 80% complete, or 20%? |
| 15:35 – 16:00 | Long break | |
| Chair: William Demopoulos |
16:00 – 16:45 | Jeffrey Bub: ‘Yes! We have no bananas’ |
| 16:45 – 16:55 | Break | |
| 16:55 – 17:40 | Commentaries from: Leah Henderson Matthew Leifer Allen Stairs |
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| 17:40 – 18:30 | General discussion |
Sunday, 12 June 2016
| 8:30 – 9:00 | Breakfast | |
| Chair: William Harper |
9:00 – 10:15 | Marissa Giustina: Significant loophole-free test of Bell’s theorem with entangled photons |
| 10:15 – 10:20 | Short break | |
| Chair: Chris Smeenk |
10:20 – 11:35 | Gilles Brassard: Information is the key! |
| 11:35 – 13:00 | Lunch | |
| Chair: James Mattingly |
13:00 – 14:15 | Lucien Hardy: Operational road to Quantum Gravity |
| 14:15 – 14:30 | Break | |
| Chair: Kerry McKenzie |
14:30 – 15:45 | Laura Felline: It’s a matter of principle. Scientific explanation in information-theoretic reconstructions of quantum theory |
| 15:45 – 16:00 | Break | |
| Chair: Robert DiSalle |
16:00 – 17:15 | Armond Duwell: Understanding quantum theory |
Workshop organisers: Wayne Myrvold, Markus Müller, Lucas Dunlap, Michael Cuffaro
Abstracts
Gilles Brassard: Information is the key!
Most physicists take it for granted that the experimental violation of Bell’s inequality provides evidence that it is not possible to completely describe the state of a physical system in terms of purely local information when this system is entangled with some other system. We disagree. Provided we redefine appropriately what is the information-theoretic state of a quantum system, it becomes possible to recover the whole from the description of its parts. This is in sharp contrast with the standard formalism of quantum mechanics in which the density matrix provides all there is to say about the state of a system. According to our formalism, there is no need to invoke supernatural nonlocality in order to explain everything standard quantum mechanics tells us that we can observe. We show, however, that this is inconsistent with the usual belief held among Everettians that the universal wavefunction can be taken as the complete representation of reality. Inspired by Plato and Kant, we introduce and contrast the notions of noumenal and phenomenal states of physical systems: the former corresponds to the complete but unknowable state of the system and the latter to what can be perceived about it with the help of arbitrary technology. We exhibit an explicit epimorphism from the former to the latter, which explains the relationship between all that there is and all that can be apprehended.
Joint work with Paul Raymond-Robichaud.
Jeffrey Bub: ‘Yes! We have no bananas’
Why write a book about quantum mechanics that’s all about bananas with stronger than quantum correlations? I’ll talk about nonlocality via superquantum PR-box correlations as the focus of Bananaworld, how the probabilistic constraints of quantum correlations characterize the structure of information in a universe with intrinsically random events, and how the measurement problem appears from this perspective.
Armond Duwell: Understanding quantum theory
In recent years there has been a shift, at least in part, in the way foundational studies of quantum theory have been undertaken. Rather than asking what the world is like if quantum theory is true, many researchers have asked the question, in the space of possible theories, why quantum theory? This is a very different approach to understanding the quantum world. In this talk I will utilize the notion of modal understanding that has been developed by Le Bihan (forthcoming) to characterize the epistemic value of this new approach, and compare it to more traditional foundational work on quantum theory.
Laura Felline: It’s a matter of principle. Scientific explanation in information-theoretic reconstructions of quantum theory
The overall aim of this paper is to explore ways in which Axiomatic Reconstructions of Quantum Theory in terms of Information-Theoretic principles (ARQITs) could contribute to explaining and understanding quantum phenomena, as well as studying their explanatory limitations. This is also done by offering an account of the kind of explanation that axiomatic reconstructions of quantum theory may provide, and re-evaluating the epistemic status of the ARQIT program in light of this explanation. On the one hand, I argue that ARQITs can aspire at providing genuine explanations of some quantum phenomena. On the other hand, I argue that such explanations cannot rule out a mechanical quantum theory, nor make it explanatorily superfluous.
Marissa Giustina: Significant loophole-free test of Bell’s theorem with entangled photons
Local realism is the worldview in which physical properties of objects exist independently of measurement and where physical influences cannot travel faster than the speed of light. Bell’s theorem states that this worldview is incompatible with the predictions of quantum mechanics, as is expressed in Bell’s inequalities. Previous experiments convincingly supported the quantum predictions. Yet, every experiment requires assumptions that provide loopholes for a local realist explanation. In this paper, I will discuss the recent results from my laboratory, in which we designed an experiment that closes the most significant of these loopholes simultaneously. Using a well-optimized source of entangled photons, rapid setting generation, and highly efficient superconducting detectors, we observe a violation of a Bell inequality with high statistical significance. The purely statistical probability of our results to occur under local realism is exceedingly unlikely, corresponding to an 11.5 standard deviation effect.
Lucien Hardy: Operational road to Quantum Gravity
Quantum theory is a probabilistic theory with fixed causal structure. General relativity is a deterministic theory but where the causal structure is dynamic. It is reasonable to expect that quantum gravity will be a probabilistic theory with dynamic causal structure. In this talk, I will outline an operational approach to Quantum Gravity within an appropriate general probability theory (GPT) framework. This consists, first, in finding an operational and probabilistic formulation of (classical) General Relativity. Usually GR is regarded as a theory in which a solution is simply stated for all space and time (the Block Universe view). Here, instead, we find a way to treat agents as making choices. Once we have this we can think about different ways to turn this classical theory into a Quantum Theory of GR.
Richard Healey: Correlations, probabilities and quantum states
In Bananaworld Jeffrey Bub advocates what he calls an information-theoretic interpretation of quantum theory. This may usefully be compared to the pragmatist approach I have been developing in recent years. We agree on many key issues, standing shoulder to shoulder against realist as well as instrumentalist enthusiasts. But I cannot accept some things he says in his book and remain puzzled by others. After locating our common ground I’ll focus on some points on which I think we disagree. Most of these have to do with the nature and function of quantum states and probabilities and what these have to do with information.
Matthew Pusey: Is QBism 80% complete, or 20%?
I will outline two views on the status of QBism, one that seems to be presumed in most discussions of the subject, and the other that I read in (or read into!) the writings of QBism’s originators. The former view is that QBism has already provided the main elements of an information-theoretic interpretation of quantum theory, perhaps with a few technical questions on SIC-POVMs and the like remaining. The latter view is eloquently summarised by Fuchs’ statement that “quantum theory is just the start of our adventure. The quantum world is still ahead of us.” I will argue that the QBism under the former view is irreparably linked to dubious ideas from the philosophy of mind (though perhaps not the ideas you expect), whilst QBism under the latter view is a promising research programme.
Rüdiger Schack: Participatory realism
Adan Cabello’s recent classification of quantum interpretations introduces the term “participatory realism” for interpretations in which measurement outcome probabilities are not determined by real properties. Examples include QBism and the Copenhagen interpretation. In this talk I compare different forms of participatory realism. I discuss what the challenges are for participatory realism, and how these challenges are met by QBism.
Robert Spekkens: Leibniz’s principle of the identity of indiscernibles as a foundational principle for quantum theory
Debates concerning the interpretation of quantum theory have always been deeply concerned with the relation between that which we posit to be real and that which we observe. Leibniz’s principle of the identity of indiscernables also concerns this relation. It asserts that if two scenarios are observationally indiscernible in principle, then any ontological account of the world should represent these two scenarios as physically identical. Einstein seems to have been deeply committed to the principle, given that the strong equivalence principle and the hole argument are both instances of it. This suggests that Leibniz’s principle should be considered as a central pillar in the conceptual foundations of general relativity. In this talk, I will explore the extent to which Leibniz’s principle may also serve as a conceptual foundation for quantum theory, specifically, within an information-theoretic approach to the reconstruction of quantum theory.