Weekly Papers on Quantum Foundations (13)

Abstract

The hypothesis (Sparenberg et al. in EPJ Web Conf 58:01016, [1]. http://dx.doi.org/10.1051/epjconf/20135801016) that the particular linear tracks appearing in the measurement of a spherically-emitting radioactive source in a cloud chamber are determined by the (random) positions of atoms or molecules inside the chamber is further explored in the framework of a recently established one-dimensional model (Carlone et al. Comm Comput Phys 18:247, [2]. http://dx.doi.org/10.4208/cicp.270814.311214a). In this model, meshes of localized spins 1/2 play the role of the cloud-chamber atoms and the spherical wave is replaced by a linear superposition of two wave packets moving from the origin to the left and to the right, evolving deterministically according to the Schrödinger equation. We first revisit these results using a time-dependent approach, where the wave packets impinge on a symmetric two-sided detector. We discuss the evolution of the wave function in the configuration space and stress the interest of a non-symmetric detector in a quantum-measurement perspective. Next we use a time-independent approach to study the scattering of a plane wave on a single-sided detector. Preliminary results are obtained, analytically for the single-spin case and numerically for up to 8 spins. They show that the spin-excitation probabilities are sometimes very sensitive to the parameters of the model, which corroborates the idea that the measurement result could be determined by the atom positions. The possible origin of decoherence and entropy increase in future models is finally discussed.

van Dongen, Jeroen (2017) The Epistemic Virtues of the Virtuous Theorist: On Albert Einstein and His Autobiography. Epistemic Virtues in the Sciences and the Humanities. Edited by Jeroen van Dongen and Herman Paul (Boston Studies in the Philosophy and History of Science, Vol. 321). pp. 63-77.
Walter, Scott A. (2018) Figures of light in the early history of relativity (1905-1914). [Preprint]
Oldofredi, Andrea (2018) No-Go Theorems and the Foundations of Quantum Physics. [Preprint]
Oldofredi, Andrea (2018) Particle Creation and Annihilation: Two Bohmian Approaches. [Preprint]

Authors: Song Ming DuYanbei Chen

It has been speculated that quantum gravity corrections may lead to modifications to space-time geometry near black hole horizons. Such structures may cause reflections to gravitational waves, causing {\it echoes} that follow the main gravitational waves from binary black hole coalescence. We show that such echoes, if exist, will give rise to a stochastic gravitational-wave background, which is very substantial if the near-horizon structure has a near unity reflectivity for gravitational waves, readily detectable by Advanced LIGO. In case reflectivity is much less than unity, the background will mainly be arising from the first echo, with a level proportional to the power reflectivity of the near-horizon structure, but robust against uncertainties in the location of the structure — as long as it is very close to the horizon. Sensitivity of third-generation detectors allows the detection of a background that corresponds to power reflectivity $\sim 10^{-3}$, if the uncertainties in the binary black-hole merger rate can be removed. We note that the echoes do alter the $f^{2/3}$ power law of the background spectra at low frequencies, which is rather robust against the uncertainties.

The Quantum Shorts competition invited stories incorporating the laws of quantum mechanics

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Abstract

It is shown that the nonlocal anomalous effective actions corresponding to the quantum breaking of the conformal symmetry can lead to observable modifications of Einstein’s equations. The fact that Einstein’s general relativity is in perfect agreement with all observations including cosmological or recently observed gravitational waves imposes strong restrictions on the field content of possible extensions of Einstein’s theory: all viable theories should have vanishing conformal anomalies. It is shown that a complete cancellation of conformal anomalies in \(D=4\) for both the \(C^2\) invariant and the Euler (Gauss–Bonnet) invariant can only be achieved for N-extended supergravity multiplets with \(N \ge 5\) .

Volume 4, Issue 2, pages 204-209

Peter J. Lewis [Show Biography]

 

 

Peter Lewis studied physics at Oxford University and philosophy at the University of California, Irvine. He has taught philosophy at Texas Tech University and the University of Miami, and he is currently Professor of Philosophy at Dartmouth College. He has been a visiting scholar at Hong Kong University, the University of Sydney, and Durham University. His work concentrates on the foundations of quantum mechanics, but he has also published on scientific realism and on the epistemology of self-locating belief.

This is a review of Shan Gao’s book The Meaning of the Wave Function: In Search of the Ontology of Quantum Mechanics (Cambridge University Press, 2017).
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Volume 4, Issue 1, pages 128-141

Ruth E. Kastner [Show Biography]

 

 

Ruth E. Kastner earned her M.S. in Physics and Ph.D. in Philosophy (History and Philosophy of Science) and the University of Maryland, College Park (1999). She has taught a variety of philosophy and physics courses throughout the Baltimore-Washington corridor, and currently is a member of the Foundations of Physics group at UMCP. She is also an Affiliate of the physics department at the SUNY Albany campus. She specializes in time-symmetry and the Transactional Interpretation (TI) of quantum mechanics, and in particular has extended the original TI of John Cramer to the relativistic domain. Her interests and publications include topics in thermodynamics and statistical mechanics, quantum ontology, counterfactuals, spacetime emergence, and free will. She is the author of two books: The Transactional Interpretation of Quantum Mechanics: The Reality of Possibility (Cambridge, 2012) and Understanding Our Unseen Reality: Solving Quantum Riddles (Imperial College Press, 2015). She is also an Editor of the collected volume Quantum Structural Studies (World Scientific, 2016).

I attempt to clear up some misunderstandings in a recent paper by Marchildon regarding the Relativistic Transactional Interpretation (RTI), showing that the negative conclusions therein regarding the transactional model are unfounded.

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Volume 4, Issue 2, pages 173-198

Mohammed Sanduk [Show Biography]

 

 

Mohammed Sanduk is an Iraqi born British physicist. He was educated at University of Baghdad and University of Manchester. Before attending his undergraduate study, he pub-lished a book in particle physics entitled “Mesons”. Sanduk has worked in industry and academia, and his last post in Iraq was head of the Laser and Opto-electronics Engineering department at Nahrain University in Baghdad. Owing to his interest in the philosophy of science, and he was a member of the academic staff of Pontifical Babel College for Philosophy. Sanduk is working with the department of chemical and process engineering at the University of Surrey. Sanduk is interested in transport of charged particles, Magnetohydro-dynamics, and the renewable energy technology. In addition to that, Sanduk is interested in the foundation of Quantum mechanics, and the philosophy of science & technology.

Based on de Broglie’s wave hypothesis and the covariant ether, the Three Wave Hypothesis (TWH) has been proposed and developed in the last century. In 2007, the author found that the TWH may be attributed to a kinematical classical system of two perpendicular rolling circles. In 2012, the author showed that the position vector of a point in a model of two rolling circles in plane can be transformed to a complex vector under a proposed effect of partial observation. In the present project, this concept of transformation is developed to be a lab observation concept. Under this transformation of the lab observer, it is found that velocity equation of the motion of the point is transformed to an equation analogising the relativistic quantum mechanics equation (Dirac equation). Many other analogies has been found, and are listed in a comparison table. The analogy tries to explain the entanglement within the scope of the transformation. These analogies may suggest that both quantum mechanics and special relativity are emergent, both of them are unified, and of the same origin. The similarities suggest analogies and propose questions of interpretation for the standard quantum theory, without any possible causal claims.

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Volume 4, Issue 2, pages 158-172

R. E. Kastner [Show Biography], Stuart Kauffman [Show Biography] and Michael Epperson [Show Biography]

 

 

 

 

Ruth E. Kastner earned her M.S. in Physics and Ph.D. in Philosophy (History and Philosophy of Science) and the University of Maryland, College Park (1999). She has taught a variety of philosophy and physics courses throughout the Baltimore-Washington corridor, and currently is a member of the Foundations of Physics group at UMCP. She is also an Affiliate of the physics department at the SUNY Albany campus. She specializes in time-symmetry and the Transactional Interpretation (TI) of quantum mechanics, and in particular has extended the original TI of John Cramer to the relativistic domain. Her interests and publications include topics in thermodynamics and statistical mechanics, quantum ontology, counterfactuals, spacetime emergence, and free will. She is the author of two books: The Transactional Interpretation of Quantum Mechanics: The Reality of Possibility (Cambridge, 2012) and Understanding Our Unseen Reality: Solving Quantum Riddles (Imperial College Press, 2015). She is also an Editor of the collected volume Quantum Structural Studies (World Scientific, 2016).

It is argued that quantum theory is best understood as requiring an ontological dualism of res extensa and res potentia, where the latter is understood per Heisenberg’s original proposal, and the former is roughly equivalent to Descartes’ ‘extended substance.’ However, this is not a dualism of mutually exclusive substances in the classical Cartesian sense, and therefore does not inherit the infamous ‘mind-body’ problem. Rather, res potentia and res extensa are understood as mutually implicative ontological extants that serve to explain the key conceptual challenges of quantum theory; in particular, nonlocality, entanglement, null measurements, and wave function collapse. It is shown that a natural account of these quantum perplexities emerges, along with a need to reassess our usual ontological commitments involving the nature of space and time.

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Abstract

I outline some of my work and results (some dating back to 1998, some more recent) on my matter-gravity entanglement hypothesis, according to which the entropy of a closed quantum gravitational system is equal to the system’s matter-gravity entanglement entropy. The main arguments presented are: (1) that this hypothesis is capable of resolving what I call the second-law puzzle, i.e. the puzzle as to how the entropy increase of a closed system can be reconciled with the asssumption of unitary time-evolution; (2) that the black hole information loss puzzle may be regarded as a special case of this second law puzzle and that therefore the same resolution applies to it; (3) that the black hole thermal atmosphere puzzle (which I recall) can be resolved by adopting a radically different-from-usual description of quantum black hole equilibrium states, according to which they are total pure states, entangled between matter and gravity in such a way that the partial states of matter and gravity are each approximately thermal equilibrium states (at the Hawking temperature); (4) that the Susskind–Horowitz–Polchinski string-theoretic understanding of black hole entropy as the logarithm of the degeneracy of a long string (which is the weak string coupling limit of a black hole) cannot be quite correct but should be replaced by a modified understanding according to which it is the entanglement entropy between a long string and its stringy atmosphere, when in a total pure equilibrium state in a suitable box, which (in line with (3)) goes over, at strong-coupling, to a black hole in equilibrium with its thermal atmosphere. The modified understanding in (4) is based on a general result, which I also describe, which concerns the likely state of a quantum system when it is weakly coupled to an energy-bath and the total state is a random pure state with a given energy. This result generalizes Goldstein et al.’s ‘canonical typicality’ result to systems which are not necessarily small.

Castellani, Elena and De Haro, Sebastian (2018) Duality, Fundamentality, and Emergence. [Preprint]

Entanglement of purification through holographic duality

Entanglement of purification through holographic duality, Published online: 26 March 2018; doi:10.1038/s41567-018-0075-2

A quantity that connects quantum information and gravity in the light of gauge/gravity correspondence is pointed out, leading to interesting properties of the entanglement of purification predicted in the holographic theories.

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