scholarly journals Contextuality, memory cost and non-classicality for sequential measurements

2019 ◽  
Vol 377 (2157) ◽  
pp. 20190141 ◽  
Author(s):  
Costantino Budroni
Keyword(s):  
Quantum Mechanics ◽  
Experimental Test ◽  
Quantum Systems ◽  
Theme Issue ◽  
Theoretical Frameworks ◽  
Temporal Correlations ◽  
Starting Point ◽  
Classical Correlations ◽  
Memory Cost ◽  
Sequential Measurements

The Kochen–Specker theorem, and the associated notion of quantum contextuality, can be considered as the starting point for the development of a notion of non-classical correlations for single systems. The subsequent debate around the possibility of an experimental test of Kochen–Specker-type contradiction stimulated the development of different theoretical frameworks to interpret experimental results. Starting from the approach based on sequential measurements, we will discuss a generalization of the notion of non-classical temporal correlations that goes beyond the contextuality approach and related ones based on Leggett and Garg's notion of macrorealism, and it is based on the notion of memory cost of generating correlations. Finally, we will review recent results on the memory cost for generating temporal correlations in classical and quantum systems. The present work is based on the talk given at the Purdue Winer Memorial Lectures 2018: probability and contextuality. This article is part of the theme issue ‘Contextuality and probability in quantum mechanics and beyond’.

scholarly journals Indistinguishability and the origins of contextuality in physics

2019 ◽  
Vol 377 (2157) ◽  
pp. 20190150 ◽  
Author(s):  
J. Acacio de Barros ◽  
Federico Holik ◽  
Décio Krause
Keyword(s):  
Quantum Mechanics ◽  
Set Theory ◽  
Physical Quantity ◽  
Theoretical Framework ◽  
Quantum Systems ◽  
Strong Sense ◽  
Theme Issue ◽  
Identity Of Indiscernibles ◽  
Theoretical Structure

In this work, we discuss a formal way of dealing with the properties of contextual systems. Our approach is to assume that properties describing the same physical quantity, but belonging to different measurement contexts, are indistinguishable in a strong sense. To construct the formal theoretical structure, we develop a description using quasi-set theory, which is a set-theoretical framework built to describe collections of elements that violate Leibnitz's principle of identity of indiscernibles. This framework allows us to consider a new ontology in order to study the properties of quantum systems. This article is part of the theme issue ‘Contextuality and probability in quantum mechanics and beyond’.

scholarly journals Phenomenological quantum thermodynamics resource theory for closed bipartite Schottky systems

2020 ◽  
Vol 378 (2170) ◽  
pp. 20190173 ◽  
Author(s):  
Wolfgang Muschik
Keyword(s):  
Quantum Mechanics ◽  
Density Operator ◽  
Nonequilibrium Thermodynamics ◽  
Discrete Systems ◽  
Resource Theory ◽  
Quantum Thermodynamics ◽  
Theme Issue ◽  
Von Neumann ◽  
Starting Point ◽  
Von Neumann Equation

How to introduce thermodynamics to quantum mechanics? From numerous possibilities of solving this task, the simple choice is here: the conventional von Neumann equation deals with a density operator whose probability weights are time-independent. Because there is no reason apart from the reversible quantum mechanics that these weights have to be time-independent, this constraint is waived, which allows one to introduce thermodynamical concepts to quantum mechanics. This procedure is similar to that of Lindblad’s equation, but different in principle. But beyond this simple starting point, the applied thermodynamical concepts of discrete systems may perform a ‘source theory’ for other versions of phenomenological quantum thermodynamics. This article is part of the theme issue ‘Fundamental aspects of nonequilibrium thermodynamics’.

scholarly journals Probing the non-classicality of temporal correlations

Quantum ◽  
2017 ◽  
Vol 1 ◽  
pp. 35 ◽  
Author(s):  
Martin Ringbauer ◽  
Rafael Chaves
Keyword(s):  
Quantum Information Processing ◽  
Quantum Correlations ◽  
Quantum Systems ◽  
Causal Modeling ◽  
Classical Counterpart ◽  
Temporal Correlations ◽  
Multiple Particles ◽  
Fair Comparison ◽  
Classical Correlations

Correlations between spacelike separated measurements on entangled quantum systems are stronger than any classical correlations and are at the heart of numerous quantum technologies. In practice, however, spacelike separation is often not guaranteed and we typically face situations where measurements have an underlying time order. Here we aim to provide a fair comparison of classical and quantum models of temporal correlations on a single particle, as well as timelike-separated correlations on multiple particles. We use a causal modeling approach to show, in theory and experiment, that quantum correlations outperform their classical counterpart when allowed equal, but limited communication resources. This provides a clearer picture of the role of quantum correlations in timelike separated scenarios, which play an important role in foundational and practical aspects of quantum information processing.

Criss-Cross: Identity and Transformation in Re-reading Billy Elliot

2016 ◽  
Vol 13 (4) ◽  
pp. 536-551
Author(s):  
Jacqui Miller
Keyword(s):  
Identity Formation ◽  
Gender And Sexuality ◽  
Central Character ◽  
Theoretical Frameworks ◽  
Liberal Politics ◽  
Starting Point ◽  
And Gender ◽  
Opening Up

Billy Elliot (2000) has been widely recognised as an important British film of the post-Thatcher period. It has been analysed using multiple disciplinary methodologies, but almost always from the theoretical frameworks of class and gender/sexuality. The film has sometimes been used not so much as a focus of analysis itself but as a conduit for exploring issues such as class deprivation or neo-liberal politics and economics. Such studies tend to use the film's perceived shortcomings as a starting point to critique society's wider failings to interrogate constructions of gender and sexuality. This article argues that an examination of the identity formation of some of the film's subsidiary characters shows how fluidity and transformation are key to the film's opening up of a jouissance which is enabled by but goes beyond its central character.

Reflections on the theme issue outcomes

2016 ◽  
Vol 8 (4) ◽  
pp. 504-510
Author(s):  
Gunjan M. Sanjeev ◽  
Richard Teare
Keyword(s):  
Customer Service ◽  
Hospitality Industry ◽  
Theme Issue ◽  
Policy Makers ◽  
Content Type ◽  
Starting Point ◽  
Cost Competitiveness ◽  
Hotel Sector ◽  
Practical Implications ◽  
Selection Of

Purpose The paper aims to profile the theme issue of Worldwide Hospitality and Tourism Themes titled “How is the need for innovation being addressed by the Indian hospitality industry?” with reference to the experiences of the theme editor, contributors from the industry and academia and the theme issue outcomes. Design/methodology/approach The paper uses structured questions to enable the theme editor to reflect on the rationale for their theme issue question, the starting-point, the selection of the writing team and material and the editorial process. Findings It highlights recent innovations that have taken place in the Indian hospitality industry especially in the areas of customer service, cost competitiveness, culinary management, revenue management and technology. Practical implications As hotel sector investment in India intensifies, this theme issue will be of interest to hoteliers, policy makers, analysts and others interested in the role that innovation can play in helping to facilitate differentiation between competing hotel products and services. Originality/value There is limited literature available on industry innovations in the Indian context. All the papers in this theme issue were written after several cycles of interaction between academics and practitioners and so they incorporate real–time, relevant and contemporary data.

scholarly journals Interesting Examples of Violation of the Classical Equivalence Principle but Not of the Weak One

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Antonio Accioly ◽  
Wallace Herdy
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Gravitational Field ◽  
Experimental Test ◽  
Equivalence Principle ◽  
Free Fall ◽  
Higher Order ◽  
Tree Level ◽  
Quantum Particles ◽  
Bohr Atom

The equivalence principle (EP) and Schiff’s conjecture are discussed en passant, and the connection between the EP and quantum mechanics is then briefly analyzed. Two semiclassical violations of the classical equivalence principle (CEP) but not of the weak one (WEP), i.e., Greenberger gravitational Bohr atom and the tree-level scattering of different quantum particles by an external weak higher-order gravitational field, are thoroughly investigated afterwards. Next, two quantum examples of systems that agree with the WEP but not with the CEP, namely, COW experiment and free fall in a constant gravitational field of a massive object described by its wave-function Ψ, are discussed in detail. Keeping in mind that, among the four examples focused on in this work only COW experiment is based on an experimental test, some important details related to it are presented as well.

scholarly journals Wigner's Problem and Alternative Commutation Relations for Quantum Mechanics

1997 ◽  
Vol 11 (10) ◽  
pp. 1281-1296 ◽  
Author(s):  
V. I. Man'ko ◽  
G. Marmo ◽  
F. Zaccaria ◽  
E. C. G. Sudarshan
Keyword(s):  
Quantum Mechanics ◽  
Vector Field ◽  
Equations Of Motion ◽  
Quantum Systems ◽  
Heisenberg Picture ◽  
Commutation Relations

It is shown that for quantum systems the vector field associated with the equations of motion may admit alternative Hamiltonian descriptions, both in the Schrödinger and Heisenberg picture. We illustrate these ambiguities in terms of simple examples.

scholarly journals Using quantum computing to create efficient algorithms

2021 ◽  
Vol 2056 (1) ◽  
pp. 012059
Author(s):  
I N Balaba ◽  
G S Deryabina ◽  
I A Pinchuk ◽  
I V Sergeev ◽  
S B Zabelina
Keyword(s):  
Quantum Mechanics ◽  
Quantum Computing ◽  
Computational Model ◽  
Exponential Growth ◽  
Quantum Algorithms ◽  
Quantum Systems ◽  
Efficient Algorithms ◽  
Historical Overview ◽  
Computing Model ◽  
Computational Strategy

Abstract The article presents a historical overview of the development of the mathematical idea of a quantum computing model - a new computational strategy based on the postulates of quantum mechanics and having advantages over the traditional computational model based on the Turing machine; clarified the features of the operation of multi-qubit quantum systems, which ensure the creation of efficient algorithms; the principles of quantum computing are outlined and a number of efficient quantum algorithms are described that allow solving the problem of exponential growth of the complexity of certain problems.

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