Weekly Papers on Quantum Foundations (12)

This is a list of this week’s papers on quantum foundations published in various journals or uploaded to preprint servers such as arxiv.org and PhilSci Archive.

A Quantum Space Behind Simple Quantum Mechanics. (arXiv:1603.05371v1 [quant-ph])

gr-qc updates on arXiv.org

on 2016-3-19 9:37am GMT

Authors: Chuan Sheng ChewOtto C. W. KongJason Payne

In physics, we are supposed to learn from experiments what constitutes a good/correct theoretical/mathematical model of any physical concept, the physical space should not be an exception. The best picture of the physical space, in Newtonian physics, is given by the configuration space of a free particle. The space, as well as the phase space, can be constructed as a representation space of the relativity symmetry. Starting with the corresponding quantum symmetry, we illustrate the construction of a quantum space along the lines of the quantum phase space and demonstrate the retrieval of the classical picture as an approximation through the contraction of the (relativity) symmetry and the representations of it. The result suggests a picture of the physical space beyond that of a finite dimensional manifold.

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Limits of time in cosmology. (arXiv:1603.05449v1 [gr-qc])

gr-qc updates on arXiv.org

on 2016-3-19 9:37am GMT

Authors: Svend E. RughHenrik Zinkernagel

We provide a discussion of some main ideas in our project about the physical foundation of the time concept in cosmology. It is standard to point to the Planck scale (located at $\sim 10^{-43}$ seconds after a fictitious “Big Bang” point) as a limit for how far back we may extrapolate the standard cosmological model. In our work we have suggested that there are several other (physically motivated) interesting limits — located at least thirty orders of magnitude before the Planck time — where the physical basis of the cosmological model and its time concept is progressively weakened. Some of these limits are connected to phase transitions in the early universe which gradually undermine the notion of ‘standard clocks’ widely employed in cosmology. Such considerations lead to a ‘scale problem’ for time which becomes particularly acute above the electroweak phase transition (before $\sim 10^{-11}$ seconds). Other limits are due to problems of building up a cosmological reference frame, or even contemplating a sensible notion of proper time, if the early universe constituents become too quantum. This ‘quantum problem’ for time arises e.g. if a pure quantum phase is contemplated at the beginning of inflation at, say, $\sim 10^{-34}$ seconds.

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Probing wave function collapse models with a classically driven mechanical oscillator. (arXiv:1504.00790v2 [quant-ph] UPDATED)

quant-ph updates on arXiv.org

on 2016-3-19 9:36am GMT

Authors: Melvyn HoAmbroise LafontNicolas SangouardPavel Sekatski

We show that the interaction of a pulsed laser light with a mechanical oscillator through the radiation pressure results in an opto-mechanical entangled state in which the photon number is correlated with the oscillator position. Interestingly, the mechanical oscillator can be delocalized over a large range of positions when driven by an intense laser light. This provides a simple yet sensitive method to probe hypothetic post-quantum theories including an explicit wave function collapse model, like the Diosi and Penrose model. We propose an entanglement witness to reveal the quantum nature of this opto-mechanical state as well as an optical technique to record the decoherence of the mechanical oscillator. We also report on a detailed feasibility study giving the experimental challenges that need to be overcome to confirm or rule out predictions from explicit wave function collapse models.

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Violation of the Born Rule: Implications for the Classical Electromagnetic Field. (arXiv:1603.05301v1 [quant-ph])

quant-ph updates on arXiv.org

on 2016-3-19 9:36am GMT

Authors: R. E. Kastner

It is shown that violation of the Born Rule leads to a breakdown of the correspondence between the quantum electromagnetic field and its classical counterpart. Specifically, the relationship of the quantum coherent state to the classical electromagnetic field turns out to imply that if the Born Rule were violated, this could result in apparent deviations from the energy conservation law applying to the field and its sources (Poynting’s Theorem). The result suggests that the Born Rule is just as fundamental a law of Nature as are the conservation laws.

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Clarifying possible misconceptions in the foundations of general relativity

PhilSci-Archive: No conditions. Results ordered -Date Deposited.

on 2016-3-19 5:51am GMT

Brown, Harvey R. and Read, James (2016) Clarifying possible misconceptions in the foundations of general relativity. [Preprint]

On Dirac’s incomplete analysis of gauge transformations

PhilSci-Archive: No conditions. Results ordered -Date Deposited.

on 2016-3-19 5:50am GMT

Pons, Josep M (2005) On Dirac’s incomplete analysis of gauge transformations. [Published Article]

[Perspective] Quantum dynamics in the smallest water droplet

Science: Current Issue

on 2016-3-18 12:00am GMT

Water plays a central role in scientific disciplines ranging from geology to astronomy to biology. Yet it is an extraordinarily dif cult liquid to understand because of its complex, ever-changing patterns of hydrogen bonds. Studies of small water clusters have provided important insights into the concerted hydrogen-bond motions that can occur in water. These studies are also crucial for developing an accurate potential function for simulating the properties of liquid water and ice (1). On page 1310 of this issue, Richardson et al. (2) provide evidence for a concerted type of motion in which two hydrogen bonds in a water cluster are broken simultaneously (see the figure). The results have implications for many areas of scientific study, including the chemistry of polar solvents, the conformations of proteins, and the dissolution of ions in minerals. Author: David C. Clary

Creating a Superposition of Unknown Quantum States

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

on 2016-3-17 2:00pm GMT

Author(s): Michał Oszmaniec, Andrzej Grudka, Michał Horodecki, and Antoni Wójcik

The superposition principle is one of the landmarks of quantum mechanics. The importance of quantum superpositions provokes questions about the limitations that quantum mechanics itself imposes on the possibility of their generation. In this work, we systematically study the problem of the creation …

 

[Phys. Rev. Lett. 116, 110403] Published Thu Mar 17, 2016

A new look at emergence. Or when after is different

Latest Results for European Journal for Philosophy of Science

on 2016-3-17 12:00am GMT

Abstract

In this paper, we put forward a new account of emergence called “transformational emergence”. Such an account captures a variety of emergence that can be considered as being diachronic and weakly ontological. The fact that transformational emergence actually constitutes a genuine form of emergence is motivated. Besides, the account is free of traditional problems surrounding more usual, synchronic versions of emergence, and it can find a strong empirical support in a specific physical phenomenon, the fractional quantum Hall effect, which has long been touted as a paradigmatic case of emergence.

The Measurement Problem: Decoherence and Convivial Solipsism

Latest Results for Foundations of Physics

on 2016-3-17 12:00am GMT

Abstract

The problem of measurement is often considered an inconsistency inside the quantum formalism. Many attempts to solve (or to dissolve) it have been made since the inception of quantum mechanics. The form of these attempts depends on the philosophical position that their authors endorse. I will review some of them and analyze their relevance. The phenomenon of decoherence is often presented as a solution lying inside the pure quantum formalism and not demanding any particular philosophical assumption. Nevertheless, a widely debated question is to decide between two different interpretations. The first one is to consider that the decoherence process has the effect to actually project a superposed state into one of its classically interpretable component, hence doing the same job as the reduction postulate. For the second one, decoherence is only a way to show why no macroscopic superposed state can be observed, so explaining the classical appearance of the macroscopic world, while the quantum entanglement between the system, the apparatus and the environment never disappears. In this case, explaining why only one single definite outcome is observed remains to do. In this paper, I examine the arguments that have been given for and against both interpretations and defend a new position, the “Convivial Solipsism”, according to which the outcome that is observed is relative to the observer, different but in close parallel to the Everett’s interpretation and sharing also some similarities with Rovelli’s relational interpretation and Quantum Bayesianism. I also show how “Convivial Solipsism” can help getting a new standpoint about the EPR paradox providing a way out of the seemingly unavoidable non-locality of quantum mechanics.

PBR theorem and sub-ensemble of quantum state

PhilSci-Archive: No conditions. Results ordered -Date Deposited.

on 2016-3-16 3:16am GMT

Kim, Minseong (2016) PBR theorem and sub-ensemble of quantum state. [Preprint]

Bohmian Classical Limit in Bounded Regions

PhilSci-Archive: No conditions. Results ordered -Date Deposited.

on 2016-3-15 6:48pm GMT

Romano, Davide (2015) Bohmian Classical Limit in Bounded Regions. [Preprint]

Isomerism and decoherence

PhilSci-Archive: No conditions. Results ordered -Date Deposited.

on 2016-3-14 4:52am GMT

Fortin, Sebastian and Lombardi, Olimpia and Martínez González, Juan Camilo (2016) Isomerism and decoherence. [Preprint]

Quantum clock: A critical discussion on spacetime. (arXiv:1603.03723v1 [gr-qc])

gr-qc updates on arXiv.org

on 2016-3-14 1:36am GMT

Authors: Luciano BurderiTiziana Di SalvoRosario Iaria

We critically discuss the measure of very short time intervals. By means of a Gedankenexperiment, we describe an ideal clock based on the occurrence of completely random events. Many previous thought experiments have suggested fundamental Planck-scale limits on measurements of distance and time. Here we present a new type of thought experiment, based on a different type of clock, that provide further support for the existence of such limits. We show that the minimum time interval $\Delta t$ that this clock can measure scales as the inverse of its size $\Delta r$. This implies an uncertainty relation between space and time: $\Delta r$ $\Delta t$ $> G \hbar / c^4$; where G, $\hbar$ and c are the gravitational constant, the reduced Planck constant, and the speed of light, respectively. We outline and briefly discuss the implications of this uncertainty conjecture.

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