Submit to Entropy Review for Entropy Propose a Special Issue

Journal Browser

► Journal Browser

Entropy in Quantum Systems and Quantum Field Theory (QFT) II

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Related Special Issue
Published Papers

A special issue of Entropy (ISSN 1099-4300). This special issue belongs to the section "Quantum Information".

Deadline for manuscript submissions: closed (30 July 2023) | Viewed by 9004

Share This Special Issue

Special Issue Editor

Prof. Dr. Ignazio Licata

E-Mail Website
Guest Editor

1. ISEM Institute for Scientific Methodology, Via Ugo La Malfa n. 153, 90146 Palermo, Italy
2. School of Advanced International Studies on Applied Theoretical and Non Linear Methodologies of Physics, 70121 Bari, Italy
Interests: foundation of quantum theories; quantum cosmology; de sitter holographic models; dissipative quantum field theories; physics of emergence and organization; fisher information; sub- and super-Turing computation models
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In these last few years, a growing interest has been expressed in entropic and informational aspects of quantum systems. In particular, we know that quantum entropy is an important index for nonlocal correlations and entanglement. Relaxation, dissipation, noise, and fluctuations in quantum open systems and in quantum field theory are concepts that run through all of physics, from elementary particles to cosmology. This Special Issue of Entropy is an invitation to scholars at deepening the theory and the applications of this important area of research.

Prof. Dr. Ignazio Licata
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Entropy is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Quantum open systems and nonequilibrium quantum field theory
Quantum fields background and particle creation
Dissipative dynamics in QM and QFT
Quantum entropies, noise, and fluctuations
Coherence and decoherence in quantum systems
Entanglement entropy in quantum field theory
Nonequilibrium quantum processes in the early universe

Related Special Issue

Entropy in Quantum Systems and Quantum Field Theory (QFT) in Entropy (4 articles)

Published Papers (4 papers)

Download All Papers

Research

10 pages, 1381 KiB

Open AccessArticle

Quantum Information Entropy for a Hyperbolic Double Well Potential in the Fractional Schrödinger Equation

by R. Santana-Carrillo, J. M. Velázquez Peto, Guo-Hua Sun and Shi-Hai Dong

Entropy 2023, 25(7), 988; https://0-doi-org.brum.beds.ac.uk/10.3390/e25070988 - 28 Jun 2023

Cited by 6 | Viewed by 1074

Abstract

In this study, we investigate the position and momentum Shannon entropy, denoted as

S_{x}

and

S_{p}

, respectively, in the context of the fractional Schrödinger equation (FSE) for a hyperbolic double well potential (HDWP). We explore various values of the fractional [...] Read more.

In this study, we investigate the position and momentum Shannon entropy, denoted as

S_{x}

and

S_{p}

, respectively, in the context of the fractional Schrödinger equation (FSE) for a hyperbolic double well potential (HDWP). We explore various values of the fractional derivative represented by k in our analysis. Our findings reveal intriguing behavior concerning the localization properties of the position entropy density,

ρ_{s} (x)

, and the momentum entropy density,

ρ_{s} (p)

, for low-lying states. Specifically, as the fractional derivative k decreases,

ρ_{s} (x)

becomes more localized, whereas

ρ_{s} (p)

becomes more delocalized. Moreover, we observe that as the derivative k decreases, the position entropy

S_{x}

decreases, while the momentum entropy

S_{p}

increases. In particular, the sum of these entropies consistently increases with decreasing fractional derivative k. It is noteworthy that, despite the increase in position Shannon entropy

S_{x}

and the decrease in momentum Shannon entropy

S_{p}

with an increase in the depth u of the HDWP, the Beckner–Bialynicki-Birula–Mycielski (BBM) inequality relation remains satisfied. Furthermore, we examine the Fisher entropy and its dependence on the depth u of the HDWP and the fractional derivative k. Our results indicate that the Fisher entropy increases as the depth u of the HDWP is increased and the fractional derivative k is decreased. Full article

(This article belongs to the Special Issue Entropy in Quantum Systems and Quantum Field Theory (QFT) II)

► Show Figures

Figure 1

14 pages, 289 KiB

Open AccessFeature PaperArticle

Entropy of Quantum Measurements

by Stanley Gudder

Entropy 2022, 24(11), 1686; https://doi.org/10.3390/e24111686 - 18 Nov 2022

Cited by 1 | Viewed by 1143

Abstract

If a is a quantum effect and

ρ

is a state, we define the

ρ

-entropy

S_{a} (ρ)

which gives the amount of uncertainty that a measurement of a provides about

ρ

. The smaller

S_{a} (ρ)

[...] Read more.

If a is a quantum effect and

ρ

is a state, we define the

ρ

-entropy

S_{a} (ρ)

which gives the amount of uncertainty that a measurement of a provides about

ρ

. The smaller

S_{a} (ρ)

is, the more information a measurement of a gives about

ρ

. In Entropy for Effects, we provide bounds on

S_{a} (ρ)

and show that if

a + b

is an effect, then

S_{a + b} (ρ) \geq S_{a} (ρ) + S_{b} (ρ)

. We then prove a result concerning convex mixtures of effects. We also consider sequential products of effects and their

ρ

-entropies. In Entropy of Observables and Instruments, we employ

S_{a} (ρ)

to define the

ρ

-entropy

S_{A} (ρ)

for an observable A. We show that

S_{A} (ρ)

directly provides the

ρ

-entropy

S_{I} (ρ)

for an instrument

I

. We establish bounds for

S_{A} (ρ)

and prove characterizations for when these bounds are obtained. These give simplified proofs of results given in the literature. We also consider

ρ

-entropies for measurement models, sequential products of observables and coarse-graining of observables. Various examples that illustrate the theory are provided. Full article

(This article belongs to the Special Issue Entropy in Quantum Systems and Quantum Field Theory (QFT) II)

8 pages, 260 KiB

Open AccessArticle

Universal Framework for Quantum Error-Correcting Codes

by Zhuo Li and Lijuan Xing

Entropy 2021, 23(8), 937; https://0-doi-org.brum.beds.ac.uk/10.3390/e23080937 - 23 Jul 2021

Cited by 2 | Viewed by 1460

Abstract

We present a universal framework for quantum error-correcting codes, i.e., a framework that applies to the most general quantum error-correcting codes. This framework is based on the group algebra, an algebraic notation associated with nice error bases of quantum systems. The nicest thing about this framework is that we can characterize the properties of quantum codes by the properties of the group algebra. We show how it characterizes the properties of quantum codes as well as generates some new results about quantum codes. Full article

(This article belongs to the Special Issue Entropy in Quantum Systems and Quantum Field Theory (QFT) II)

30 pages, 3443 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Bell Diagonal and Werner State Generation: Entanglement, Non-Locality, Steering and Discord on the IBM Quantum Computer

by Elias Riedel Gårding, Nicolas Schwaller, Chun Lam Chan, Su Yeon Chang, Samuel Bosch, Frederic Gessler, Willy Robert Laborde, Javier Naya Hernandez, Xinyu Si, Marc-André Dupertuis and Nicolas Macris

Entropy 2021, 23(7), 797; https://0-doi-org.brum.beds.ac.uk/10.3390/e23070797 - 23 Jun 2021

Cited by 14 | Viewed by 4466

Abstract

We propose the first correct special-purpose quantum circuits for preparation of Bell diagonal states (BDS), and implement them on the IBM Quantum computer, characterizing and testing complex aspects of their quantum correlations in the full parameter space. Among the circuits proposed, one involves only two quantum bits but requires adapted quantum tomography routines handling classical bits in parallel. The entire class of Bell diagonal states is generated, and several characteristic indicators, namely entanglement of formation and concurrence, CHSH non-locality, steering and discord, are experimentally evaluated over the full parameter space and compared with theory. As a by-product of this work, we also find a remarkable general inequality between “quantum discord” and “asymmetric relative entropy of discord”: the former never exceeds the latter. We also prove that for all BDS the two coincide. Full article

(This article belongs to the Special Issue Entropy in Quantum Systems and Quantum Field Theory (QFT) II)

► Show Figures