scholarly journals Enhancement of superluminal weak values under Lorentz boost

2020 ◽  
Vol 35 (34) ◽  
pp. 2050279
Author(s):  
Abhishek Som ◽  
Sourin Das
Keyword(s):  
Probability Distribution ◽  
Group Velocity ◽  
Local Group ◽  
Total Probability ◽  
Weak Values ◽  
Dirac Theory ◽  
Lorentz Boost ◽  
Weak Value ◽  
Klein Gordon

The local group velocity defined as the weak value of the velocity operator in (1 + 1)-dimensional Klein-Gordon and Dirac theory is studied. As shown by Berry [J. Phys. A  45, 185308 (2012)], when the pre- and post-selected states for evaluating the weak value are chosen at random from an ensemble of available states, it gives rise to a universal probability distribution for the local group velocity which can have both subluminal and superluminal components. In this work, we explore the possibility of enhancement of the superluminal fraction of this total probability distribution by applying a Lorentz boost and show that it can indeed be enhanced both in the case of Klein–Gordon and Dirac theories.

scholarly journals Weak value controversy

2017 ◽  
Vol 375 (2106) ◽  
pp. 20160395 ◽  
Author(s):  
L. Vaidman
Keyword(s):  
Quantum System ◽  
Precision Measurements ◽  
Weak Values ◽  
Statistical Nature ◽  
Weak Value ◽  
Quantum Revolution

Recent controversy regarding the meaning and usefulness of weak values is reviewed. It is argued that in spite of recent statistical arguments by Ferrie and Combes, experiments with anomalous weak values provide useful amplification techniques for precision measurements of small effects in many realistic situations. The statistical nature of weak values is questioned. Although measuring weak values requires an ensemble, it is argued that the weak value, similarly to an eigenvalue, is a property of a single pre- and post-selected quantum system. This article is part of the themed issue ‘Second quantum revolution: foundational questions’.

scholarly journals Weak-value amplification: state of play

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
George C. Knee ◽  
Joshua Combes ◽  
Christopher Ferrie ◽  
Erik M. Gauger
Keyword(s):  
Quantum Theory ◽  
Signal Amplification ◽  
Weak Measurement ◽  
Experimental Results ◽  
Weak Values ◽  
Theoretical Studies ◽  
Weak Value ◽  
Metrological Performance ◽  
Weak Value Amplification ◽  
Theory And Experiment

AbstractWeak values arise in quantum theory when the result of a weak measurement is conditioned on a subsequent strong measurement. The majority of the trials are discarded, leaving only very few successful events. Intriguingly those can display a substantial signal amplification. This raises the question of whether weak values carry potential to improve the performance of quantum sensors, and indeed a number of impressive experimental results suggested this may be the case. By contrast, recent theoretical studies have found the opposite: using weak-values to obtain an amplification generally worsens metrological performance. This survey summarises the implications of those studies, which call for a reappraisal of weak values’ utility and for further work to reconcile theory and experiment.

scholarly journals Use Of Bayesian Networks And Augmented Reality To Reliability Testing Of Complex Technical Objects

2015 ◽  
Vol 35 (1) ◽  
pp. 179-190
Author(s):  
Tomasz Wójcicki
Keyword(s):  
Augmented Reality ◽  
Probability Distribution ◽  
Information Technologies ◽  
Total Probability ◽  
Reliability Testing ◽  
Basic Functions ◽  
Modern Information ◽  
Effective Visualization ◽  
Visualization Techniques ◽  
Data Processing Methods

Abstract This paper presents a methodology developed to support the tests of reliability of complex technical objects. The presented methodology covers the use of modern information technologies in the form of algorithmic models and effective visualization techniques in the form of augmented reality. The possibility of using a probabilistic Bayesian network. The method of determining the probabilities for specific nodes, and the total probability distribution of graph structures are presented. The structure of the model and its basic functions are shown. The results of the verification work for connecting data processing methods and visualization techniques based on augmented reality are presented.

scholarly journals Annihilation of the scalar pair into a photon in a de Sitter universe

2016 ◽  
Vol 31 (14n15) ◽  
pp. 1650081 ◽  
Author(s):  
Mihaela-Andreea Băloi
Keyword(s):  
Photon Emission ◽  
Total Probability ◽  
De Sitter ◽  
Expansion Factor ◽  
Scalar Particles ◽  
Gravitational Fields ◽  
Klein Gordon ◽  
De Sitter Universe ◽  
Mass Expansion ◽  
Strong Gravitational Fields

The annihilation of massive scalar particles in one photon in de Sitter expanding universe is studied, using perturbative QED. The amplitude and probability corresponding to this process is computed using the exact solutions of the Klein–Gordon and Maxwell equations on de Sitter geometry. Our results show that the expression of the total probability of photon emission is a function dependent on the ratio mass/expansion factor. We perform a graphical study of the total probability in terms of the parameter mass/expansion factor, showing that this effect is significant only in strong gravitational fields. We also obtain that the total probability for this process vanishes in the Minkowski limit.

scholarly journals The Tully-Fisher Relation and its Application to the Distance Scale

1983 ◽  
Vol 6 ◽  
pp. 269-282 ◽  
Author(s):  
M. Aaronson
Keyword(s):  
Group Velocity ◽  
Deceleration Parameter ◽  
Local Group ◽  
Hubble Constant ◽  
Distance Scale ◽  
Expansion Rate ◽  
Distance Indicator ◽  
Fisher Relation ◽  
Hubble Flow ◽  
Local Value

AbstractThe Tully-Fisher relation applied in the infrared appears to be the best global distance indicator presently available for determining the expansion rate and deviations from uniform Hubble flow. In this article recent results obtained using the IR/H I method are reviewed. A Virgo-directed Local Group velocity of about 300 km s–1 is indicated (implying a local value for the deceleration parameter qo ~ 0.05 – 0.1) along with a “best guess” value for the Hubble Constant of 85 km s-1 Mpc-1.

scholarly journals Local Group Velocity from the PSCz and BTP Surveys

2004 ◽  
Vol 21 (4) ◽  
pp. 415-417 ◽  
Author(s):  
Kenton J. D'Mellow ◽  
Will Saunders ◽  
Keyword(s):  
Group Velocity ◽  
Systematic Uncertainty ◽  
Local Group ◽  
Galactic Plane ◽  
Significant Component ◽  
Preliminary Results ◽  
Gravitational Pull

AbstractWe present a brief overview and preliminary measure of the Local Group velocity, using the PSCz survey together with its recently completed extension into the Galactic plane, the Behind The Plane (BTP) survey. The addition of the BTP has increased the total sky coverage from 84% to 93%, drastically reducing the systematic uncertainty in the direction of the local gravitational pull caused by incomplete sky coverage. We present methods that self-consistently determine the acceleration in the presence of redshift distortions. Preliminary results suggest that the dipole converges within the survey limiting depth. There is a large, but only marginally significant, component to the dipole arising at 180–200 h–1 Mpc.

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