# Searching for quantum black hole structure with the Event Horizon Telescope. (arXiv:1904.05287v1 [gr-qc] CROSS LISTED)

## hep-th updates on arXiv.org

Authors: Steven B. Giddings

The impressive images from the Event Horizon Telescope sharpen the conflict between our observations of gravitational phenomena and the principles of quantum mechanics. Two related scenarios for reconciling quantum mechanics with the existence of black hole-like objects, with “minimal” departure from general relativity and local quantum field theory, have been explored; one of these could produce signatures visible to EHT observations. A specific target is temporal variability of images, with a characteristic time scale determined by the classical black hole radius. The absence of evidence for such variability in the initial observational span of seven days is not expected to strongly constrain such variability. Theoretical and observational next steps towards investigating such scenarios are outlined.

# Stochastic Bohmian mechanics within the Schr\”{o}dinger-Langevin framework: A trajectory analysis of wave-packet dynamics in a fluctuative-dissipative medium. (arXiv:1902.02147v2 [quant-ph] UPDATED)

## quant-ph updates on arXiv.org

Authors: S. V. Mousavi, S. Miret-Artés

A Bohmian analysis of the so-called Schr\”{o}dinger-Langevin or Kostin nonlinear differential equation is provided to study how thermal fluctuations of the environment affects the dynamics of the wave packet from a quantum hydrodynamical point of view. In this way, after obtaining the Schr\”{o}dinger-Langevin-Bohm equation from the Kostin equation its application to simple but physically insightful systems such as the Brownian-Bohmian motion, motion in a gravity field and transmission through a parabolic repeller is studied. % If a time-dependent Gaussian ansatz for the probability density is assumed, the effect of thermal fluctuations together with thermal wave packets leads to Bohmian stochastic trajectories. From this trajectory based analysis, quantum and classical diffusion coefficients for free particles, thermal arrival times for a linear potential and transmission probabilities and characteristic times such as arrival and dwell times for a parabolic repeller are then presented and discussed.

# Entanglement, decoherence, and measurement

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# Post-Newtonian corrections to Schrödinger equations in gravitational fields

## Classical and Quantum Gravity – latest papers

# On the Universality of Hawking Radiation

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# Assessing Scientific Theories: The Bayesian Approach

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# On Representational Redundancy, Surplus Structure, and the Hole Argument

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# Reformulation of quantum mechanics and strong complementarity from Bayesian inference requirements

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**Correlations detected in a quantum vacuum**

Correlations detected in a quantum vacuum, Published online: 10 April 2019; doi:10.1038/d41586-019-01083-z

A vacuum as described by quantum mechanics is perhaps the most fundamental but mysterious state in physics. The discovery of correlations between electric-field fluctuations in such a vacuum represents a major advance.

**A realist takes on quantum mechanics**

A realist takes on quantum mechanics, Published online: 09 April 2019; doi:10.1038/d41586-019-01101-0

Graham Farmelo parses Lee Smolin’s takedown of the most successful physics theory ever.

# Friedman and Some of his Critics on the Foundations of General Relativity

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# Emergence and Correspondence for String Theory Black Holes

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# Conceptual Analysis of Black Hole Entropy in String Theory

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# Emergence, Functionalism and Pragmatic Reality in Wallacian quantum mechanics

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# A Realist View of the Quantum World

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# Is Time Travel Too Strange to Be Possible? – Determinism and Indeterminism on Closed Timelike Curves

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# The Descriptive and Normative Versions of Scientific Realism and Pessimism

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# Experimental Investigation of Quantum Decay at Short, Intermediate, and Long Times via Integrated Photonics

## PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Author(s): Andrea Crespi, Francesco V. Pepe, Paolo Facchi, Fabio Sciarrino, Paolo Mataloni, Hiromichi Nakazato, Saverio Pascazio, and Roberto Osellame

The decay of an unstable system is usually described by an exponential law. Quantum mechanics predicts strong deviations of the survival probability from the exponential: Indeed, the decay is initially quadratic, while at very large times it follows a power law, with superimposed oscillations. The l…

[Phys. Rev. Lett. 122, 130401] Published Wed Apr 03, 2019

# About Wigner Friend’s and Hardy’s paradox in a Bohmian approach: a comment of “Quantum theory cannot consistently describe the use of itself”

## International Journal of Quantum Foundations – International Journal of Quantum Foundations

*Volume 5, Issue 2, pages 80-97*

Aurélien Drezet [Show Biography]

This is an analysis of the recently published article “Quantum theory cannot consistently describe the use of itself” by D. Frauchiger and R. Renner [1]. Here I decipher the paradox and analyze it from the point of view of de Broglie-Bohm hidden variable theory (i.e., Bohmian mechanics). I also analyze the problem from the perspective obtained by the Copenhagen interpretation (i.e., the Bohrian interpretation) and show that both views are self consistent and do not lead to any contradiction with a `single-world’ description of quantum theory.

# Is There a Physical Reason Beyond the Imaginary i in the Quantum Mechanics Formulation?

## International Journal of Quantum Foundations – International Journal of Quantum Foundations

*Volume 5, Issue 2, pages 69-79*

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.

The imaginary *i* in the formulation of the quantum mechanics is accepted within the axioms of the quantum mechanics theory, and, thus, there is no need for an explanation of its origin. Since 2012, in a non-quantum mechanics project, there has been an attempt to complexify a real function and build an analogy for relativistic quantum mechanics. In that theoretical attempt, a partial observation technique is proposed as one of the reasons behind the appearance of the imaginary *i*. The present article throws light on that attempt of complexification and tries to explain the logic of physics behind the complex phase factor. This physical process of partial observation acts as a process of physicalization of a virtual model. According to the positive results of analogy, the appeared imaginary *i* in quantum mechanics formulation *may b*e related to a partial observation case as well.

# Reality and the Probability Wave

## International Journal of Quantum Foundations – International Journal of Quantum Foundations

*Volume 5, Issue 2, pages 51-68*

Daniel Shanahan [Show Biography]

Dan Shanahan is an independent researcher with a passion for foundational issues in quantum theory and relativity. Born in Perth, Western Australia, he studied physics at the Universities of NSW and Sydney.

Effects associated in quantum mechanics with a divisible probability wave are

explained as physically real consequences of the equal but opposite reaction

of the apparatus as a particle is measured. Taking as illustration a

Mach-Zehnder interferometer operating by refraction, it is shown that this

reaction must comprise a fluctuation in the reradiation field of complementary

effect to the changes occurring in the photon as it is projected into one or

other path. The evolution of this fluctuation through the experiment will

explain the alternative states of the particle discerned in self interference,

while the maintenance of equilibrium in the face of such fluctuations becomes

the source of the Born probabilities. In this scheme, the probability wave

is a mathematical artifact, epistemic rather than ontic, and akin in this

respect to the simplifying constructions of geometrical optics.

# Wave Function Collapse and the No-Superluminal-Signaling Principle

## International Journal of Quantum Foundations – International Journal of Quantum Foundations

*Volume 5, Issue 2, pages 16-50*

Edward J. Gillis [Show Biography]

Ed Gillis received his B. A. in Philosophy from the University of Michigan, and his Ph.D in Physics from the University of Colorado for research on the relationship between quantum nonlocality and relativity. He has authored several papers on quantum foundations, dealing, in particular, with connections between wave function collapse and elementary processes, how these connections might lead to an explanation of the no-superluminal-signaling principle in fundamental physical terms, and possible tests for collapse. He has also worked as an engineer on the development of sensor systems and control algorithms based on the information provided by those systems.

The assumption that wave function collapse is a real occurrence has very interesting consequences – both experimental and theoretical. Besides predicting observable deviations from linear evolution, it implies that these deviations must originate in nondeterministic effects at the elementary level in order to prevent superluminal signaling, as demonstrated by Gisin. This lack of determinism implies that information cannot be instantiated in a reproducible form in isolated microsystems (as illustrated by the No-cloning theorem). By stipulating that information is a reproducible and referential property of physical systems, one can formulate the no-signaling principle in strictly physical terms as a prohibition of the acquisition of information about spacelike-separated occurrences. This formulation provides a new perspective on the relationship between relativity and spacetime structure, and it imposes tight constraints on the way in which collapse effects are induced. These constraints indicate that wave function collapse results from (presumably small) nondeterministic deviations from linear evolution associated with nonlocally entangling interactions. This hypothesis can be formalized in a stochastic collapse equation and used to assess the feasibility of testing for collapse effects.

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