scholarly journals Biorthogonal quantum mechanics: super-quantum correlations and expectation values without definite probabilities

2013 ◽  
Vol 46 (48) ◽  
pp. 485306 ◽  
Author(s):  
Lay Nam Chang ◽  
Zachary Lewis ◽  
Djordje Minic ◽  
Tatsu Takeuchi
Keyword(s):  
Quantum Mechanics ◽  
Quantum Correlations ◽  
Expectation Values

scholarly journals ABCD of ’t Hooft operators

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Hirotaka Hayashi ◽  
Takuya Okuda ◽  
Yutaka Yoshida
Keyword(s):  
Quantum Mechanics ◽  
Gauge Theories ◽  
Supersymmetric Quantum Mechanics ◽  
Type Ii ◽  
Expectation Values ◽  
String Theories

Abstract We compute by supersymmetric localization the expectation values of half-BPS ’t Hooft line operators in $$ \mathcal{N} $$ N = 2 U(N ), SO(N ) and USp(N ) gauge theories on S1 × ℝ3 with an Ω-deformation. We evaluate the non-perturbative contributions due to monopole screening by calculating the supersymmetric indices of the corresponding supersymmetric quantum mechanics, which we obtain by realizing the gauge theories and the ’t Hooft operators using branes and orientifolds in type II string theories.

scholarly journals Quantum Mechanics and Global Determinism

Quanta ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 40 ◽  
Author(s):  
Emily Christine Adlam
Keyword(s):  
Quantum Mechanics ◽  
Quantum Correlations ◽  
Deterministic Theory ◽  
No Signaling ◽  
Open Question ◽  
Global Determinism

It is proposed that certain features of quantum mechanics may be perspectival effects, which arise because experiments performed on locally accessible variables can only uncover a certain subset of the correlations exhibited by an underlying deterministic theory. This hypothesis is used to derive the no-signaling principle, thus resolving an open question regarding the apparently fine-tuned nature of quantum correlations. Some potential objections to this approach are then discussed and answered.Quanta 2018; 7: 40–53.

scholarly journals Effective quantum tunneling from a semiclassical momentous approach

2020 ◽  
Vol 34 (29) ◽  
pp. 2050271
Author(s):  
L. Aragón-Muñoz ◽  
G. Chacón-Acosta ◽  
H. Hernandez-Hernandez
Keyword(s):  
Dynamical System ◽  
Quantum Mechanics ◽  
Potential Barrier ◽  
Quantum Tunneling ◽  
Time Dependent ◽  
Tunnel Effect ◽  
Expectation Values ◽  
Effective Time ◽  
Dependent Potential ◽  
Individual Particles

In this work, we study the quantum tunnel effect through a potential barrier within a semiclassical formulation of quantum mechanics based on expectation values of configuration variables and quantum dispersions as dynamical variables. The evolution of the system is given in terms of a dynamical system for which we are able to determine numerical effective trajectories for individual particles, similar to the Bohmian description of quantum mechanics. We obtain a complete description of the possible trajectories of the system, finding semiclassical reflected, tunneled and confined paths due to the appearance of an effective time-dependent potential.

scholarly journals Reality, Indeterminacy, Probability, and Information in Quantum Theory

Entropy ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 747
Author(s):  
Arkady Plotnitsky
Keyword(s):  
Information Theory ◽  
Quantum Mechanics ◽  
Quantum Theory ◽  
Quantum Information ◽  
Quantum Correlations ◽  
Quantum Information Theory ◽  
Quantum Phenomena

Following the view of several leading quantum-information theorists, this paper argues that quantum phenomena, including those exhibiting quantum correlations (one of their most enigmatic features), and quantum mechanics may be best understood in quantum-informational terms. It also argues that this understanding is implicit already in the work of some among the founding figures of quantum mechanics, in particular W. Heisenberg and N. Bohr, half a century before quantum information theory emerged and confirmed, and gave a deeper meaning to, to their insights. These insights, I further argue, still help this understanding, which is the main reason for considering them here. My argument is grounded in a particular interpretation of quantum phenomena and quantum mechanics, in part arising from these insights as well. This interpretation is based on the concept of reality without realism, RWR (which places the reality considered beyond representation or even conception), introduced by this author previously, in turn, following Heisenberg and Bohr, and in response to quantum information theory.

Conditional expectation values in quantum mechanics

1987 ◽  
Vol 17 (6) ◽  
pp. 561-574 ◽  
Author(s):  
Leon Cohen ◽  
Chongmoon Lee
Keyword(s):  
Quantum Mechanics ◽  
Conditional Expectation ◽  
Expectation Values

scholarly journals Proposal to Test a Transient Deviation from Quantum Mechanics’ Predictions for Bell’s Experiment

Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1589
Author(s):  
Alejandro Andrés Hnilo ◽  
Monica Beatriz Agüero ◽  
Marcelo Gregorio Kovalsky
Keyword(s):  
Quantum Mechanics ◽  
Hidden Variables ◽  
Quantum Correlations ◽  
Entangled State ◽  
Particle Detection ◽  
Specific Test ◽  
Nonlinear Operators ◽  
Model Following ◽  
Proposed Model ◽  
Faster Than Light

Quantum mechanics predicts correlations between measurements performed in distant regions of a spatially spread entangled state to be higher than allowed by intuitive concepts of Locality and Realism. These high correlations forbid the use of nonlinear operators of evolution (which would be desirable for several reasons), for they may allow faster-than-light signaling. As a way out of this situation, it has been hypothesized that the high quantum correlations develop only after a time longer than L/c has elapsed (where L is the spread of the entangled state and c is the velocity of light). In shorter times, correlations compatible with Locality and Realism would be observed instead. A simple hidden variables model following this hypothesis is described. It is based on a modified Wheeler–Feynman theory of radiation. This hypothesis has not been disproved by any of the experiments performed to date. A test achievable with accessible means is proposed and described. It involves a pulsed source of entangled states and stroboscopic record of particle detection during the pulses. Data recorded in similar but incomplete optical experiments are analyzed, and found consistent with the proposed model. However, it is not claimed, in any sense, that the hypothesis has been validated. On the contrary, it is stressed that a complete, specific test is absolutely needed.

scholarly journals Causation does not explain contextuality

Quantum ◽  
2018 ◽  
Vol 2 ◽  
pp. 63 ◽  
Author(s):  
Sally Shrapnel ◽  
Fabio Costa
Keyword(s):  
Quantum Mechanics ◽  
Causal Structure ◽  
Quantum Correlations ◽  
Global Constraints ◽  
Local Constraints ◽  
The Past ◽  
Interpretations Of Quantum Mechanics ◽  
The World ◽  
Non Local ◽  
Initial States

Realist interpretations of quantum mechanics presuppose the existence of elements of reality that are independent of the actions used to reveal them. Such a view is challenged by several no-go theorems that show quantum correlations cannot be explained by non-contextual ontological models, where physical properties are assumed to exist prior to and independently of the act of measurement. However, all such contextuality proofs assume a traditional notion of causal structure, where causal influence flows from past to future according to ordinary dynamical laws. This leaves open the question of whether the apparent contextuality of quantum mechanics is simply the signature of some exotic causal structure, where the future might affect the past or distant systems might get correlated due to non-local constraints. Here we show that quantum predictions require a deeper form of contextuality: even allowing for arbitrary causal structure, no model can explain quantum correlations from non-contextual ontological properties of the world, be they initial states, dynamical laws, or global constraints.

scholarly journals Relativistic independence bounds nonlocality

2019 ◽  
Vol 5 (4) ◽  
pp. eaav8370 ◽  
Author(s):  
Avishy Carmi ◽  
Eliahu Cohen
Keyword(s):  
Quantum Mechanics ◽  
Quantum Correlations ◽  
Physical Principle ◽  
Quantum Nonlocality ◽  
Measuring Instruments ◽  
Uncertainty Relations ◽  
The Past ◽  
Nonlocal Correlations

If nature allowed nonlocal correlations other than those predicted by quantum mechanics, would that contradict some physical principle? Various approaches have been put forward in the past two decades in an attempt to single out quantum nonlocality. However, none of them can explain the set of quantum correlations arising in the simplest scenarios. Here, it is shown that generalized uncertainty relations, as well as a specific notion of locality, give rise to both familiar and new characterizations of quantum correlations. In particular, we identify a condition, relativistic independence, which states that uncertainty relations are local in the sense that they cannot be influenced by other experimenters’ choices of measuring instruments. We prove that theories with nonlocal correlations stronger than the quantum ones do not satisfy this notion of locality, and therefore, they either violate the underlying generalized uncertainty relations or allow experimenters to nonlocally tamper with the uncertainty relations of their peers.

scholarly journals The problem of quantum correlations and the totalitarian principle

2019 ◽  
Vol 377 (2157) ◽  
pp. 20190136 ◽  
Author(s):  
Adán Cabello
Keyword(s):  
Quantum Mechanics ◽  
Quantum Correlations ◽  
Short Version ◽  
Theme Issue ◽  
Independent Realization

The totalitarian principle establishes that ‘anything not forbidden is compulsory’. The problem of quantum correlations is explaining what selects the set of quantum correlations for a Bell and Kochen–Specker (KS) contextuality scenario. Here, we show that two assumptions and a version of the totalitarian principle lead to the quantum correlations. The assumptions are that there is a non-empty set of correlations for any KS contextuality scenario and a statistically independent realization of any two KS experiments. The version of the totalitarian principle says that any correlation not forbidden by these assumptions can be produced. This paper contains a short version of the proof (presented elsewhere) and explores some implications of the result. This article is part of the theme issue ‘Contextuality and probability in quantum mechanics and beyond’.

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