Quantum entanglement and violation of Bell’s inequality in dipolar interaction system under Dzyaloshinsky–Moriya interaction

2020 ◽  
Vol 35 (17) ◽  
pp. 2050138
Author(s):  
Nabil Habiballah ◽  
Ahmed Salah ◽  
Larbi Jebli ◽  
Mohamed Amazioug ◽  
Jamal El Qars ◽  
...  
Keyword(s):  
Quantum Entanglement ◽  
Thermal State ◽  
Dipolar Interaction ◽  
Quantum Spin ◽  
Von Neumann Entropy ◽  
Thermal Entanglement ◽  
Dm Interaction ◽  
Von Neumann ◽  
Quantum Spin Models ◽  
Non Locality

The Dzyaloshinsky–Moriya (DM) interaction contributes to some unusual and interesting magnetic properties in real materials, thus playing an important role in the degree of quantum entanglement in Heisenberg quantum spin models. In [C. S. Castro, O. S. Duarte, D. P. Pires, D. O. Soares-Pinto and M. S. Reis, Phys. Lett. A 380, 1571 (2016)], it has been investigated about the non-locality and the thermal entanglement in a dipolar spin thermal system without DM interaction. In this work, we study the entanglement in the thermal state of inhomogeneous Heisenberg coupling under the presence of the DM interaction along the [Formula: see text]-axis. More precisely, we analyze the effect of the DM interaction on non-locality phenomena and quantum entanglement as measured by negativity and Von Neumann entropy. We show that by comparing with [C. S. Castro, O. S. Duarte, D. P. Pires, D. O. Soares-Pinto and M. S. Reis, Phys. Lett. A 380, 1571 (2016)], the local quantum states become more pronounced, when the DM interaction is taken into account. This fact is well confirmed by noting that Von Neumann entropy is destroyed in the presence of the DM interaction. It can be deduced that the Dzyaloshinsky–Moriya (DM) interaction makes the thermal states less correlated.

Generalized Nonadditive Information Theory and Quantum Entanglement

2004 ◽  
Author(s):  
Sumiyoshi Abe
Keyword(s):  
Information Theory ◽  
Quantum Theory ◽  
Statistical Mechanics ◽  
Quantum Entanglement ◽  
Theory Of Measurement ◽  
Conditional Entropy ◽  
Tsallis Entropy ◽  
Von Neumann Entropy ◽  
Additive Theory ◽  
Von Neumann

Nonadditive classical information theory is developed in the axiomatic framework and then translated into quantum theory. The nonadditive conditional entropy associated with the Tsallis entropy indexed by q is given in accordance with the formalism of nonextensive statistical mechanics. The theory is applied to the problems of quantum entanglement and separability of the Werner-Popescu-type mixed state of a multipartite system, in order to examine if it has any points superior to the additive theory with the von Neumann entropy realized in the limit q → 1. It is shown that the nonadditive theory can lead to the necessary and sufficient condition for separability of the Werner-Popescu-type state, whereas the von Neumann theory can give only a much weaker condition…. Tsallis' nonextensive generalization of Boltzmann-Gibbs statistical mechanics [3, 15, 16] and its success in describing behaviors of a large class of complex systems naturally lead to the question of whether information theory can also admit an analogous generalization. If the answer is affirmative, then that will be of particular importance in connection with the problem of quantum entanglement and quantum theory of measurement [6, 8], in which necessities of a nonadditive information measure and an information content are suggested. One should also remember that there exists a conceptual similarity between a complex system and an entangled quantum system. In these systems, a "part" is indivisibly connected with the rest. An external operation on any part drastically influences the whole system, in general. Thus, the traditional reductionistic approach to an understanding of the nature of such a system may not work efficiently. In this chapter, we report a recent development in nonadditive quantum information theory based on the Tsallis entropy indexed by q [15] and its associated nonadditive conditional entropy [1]. This theory includes the ordinary additive theory with the von Neumann entropy in a special limiting case: q → To see if it has points superior to the additive theory, we apply it to the problems of separability and quantum entanglement.

scholarly journals Quantum thermodynamics and quantum entanglement entropies in an expanding universe

2017 ◽  
Vol 32 (15) ◽  
pp. 1750066 ◽  
Author(s):  
Mehrnoosh Farahmand ◽  
Hosein Mohammadzadeh ◽  
Hossein Mehri-Dehnavi
Keyword(s):  
Scalar Field ◽  
Quantum Entanglement ◽  
Particle Creation ◽  
Space Time ◽  
Von Neumann Entropy ◽  
Quantum Thermodynamics ◽  
Entanglement Generation ◽  
Von Neumann ◽  
Underlying Space ◽  
The Universe

We investigate an asymptotically spatially flat Robertson–Walker space–time from two different perspectives. First, using von Neumann entropy, we evaluate the entanglement generation due to the encoded information in space–time. Then, we work out the entropy of particle creation based on the quantum thermodynamics of the scalar field on the underlying space–time. We show that the general behavior of both entropies are the same. Therefore, the entanglement can be applied to the customary quantum thermodynamics of the universe. Also, using these entropies, we can recover some information about the parameters of space–time.

scholarly journals ENTANGLEMENT OF QUANTUM SPIN SYSTEMS: A VALENCE-BOND APPROACH

2011 ◽  
Vol 25 (12n13) ◽  
pp. 917-928 ◽  
Author(s):  
SYLVAIN CAPPONI ◽  
FABIEN ALET ◽  
MATTHIEU MAMBRINI
Keyword(s):  
Quantum System ◽  
Valence Bond ◽  
Quantum Spin ◽  
Spin Systems ◽  
Von Neumann Entropy ◽  
Quantum Spin Systems ◽  
Von Neumann ◽  
Open Issue

In order to quantify entanglement between two parts of a quantum system, one of the most used estimators is the Von Neumann entropy. Unfortunately, computing this quantity for large interacting quantum spin systems remains an open issue. Faced with this difficulty, other estimators have been proposed to measure entanglement efficiently, mostly by using simulations in the valence-bond basis. We review the different proposals and try to clarify the connections between their geometric definitions and proper observables. We illustrate this analysis with new results of entanglement properties of spin-1 chains.

scholarly journals Entanglement Dynamics of Three and Four Level Atomic System under Stark Effect and Kerr-Like Medium

2019 ◽  
Vol 1 (1) ◽  
pp. 23-36
Author(s):  
S. Jamal Anwar ◽  
M. Ramzan ◽  
M. Usman ◽  
M. Khalid Khan
Keyword(s):  
Quantum Entanglement ◽  
Stark Effect ◽  
Quantum Fisher Information ◽  
Local Maximum ◽  
Stark Shift ◽  
Von Neumann Entropy ◽  
Kerr Medium ◽  
Von Neumann ◽  
Atomic Systems ◽  
Non Linear

We investigated numerically the dynamics of quantum Fisher information (QFI) and entanglement for three- and four-level atomic systems interacting with a coherent field under the effect of Stark shift and Kerr medium. It was observed that the Stark shift and Kerr-like medium play a prominent role during the time evolution of the quantum systems. The non-linear Kerr medium has a stronger effect on the dynamics of QFI as compared to the quantum entanglement (QE). QFI is heavily suppressed by increasing the value of Kerr parameter. This behavior was found comparable in the cases of three- and four-level atomic systems coupled with a non-linear Kerr medium. However, QFI and quantum entanglement (QE) maintain their periodic nature under atomic motion. On the other hand, the local maximum value of QFI and von Neumann entropy (VNE) decrease gradually under the Stark effect. Moreover, no prominent difference in the behavior of QFI and QE was observed for three- and four-level atoms while increasing the value of Stark parameter. However, three- and four-level atomic systems were found equally prone to the non-linear Kerr medium and Stark effect. Furthermore, three- and four-level atomic systems were found fully prone to the Kerr-like medium and Stark effect.

Entanglement for excited states of ultracold bosonic atoms in one-dimensional harmonic traps with contact interaction

2015 ◽  
Vol 29 (30) ◽  
pp. 1550189 ◽  
Author(s):  
Hsuan Tung Peng ◽  
Yew Kam Ho
Keyword(s):  
Quantum Entanglement ◽  
Excited States ◽  
Ground State ◽  
The Other ◽  
Von Neumann Entropy ◽  
Von Neumann ◽  
One Dimensional ◽  
Ultracold Bosonic Atoms ◽  
Bosonic Atoms ◽  
Atom System

We have investigated quantum entanglement for two interacting ultracold bosonic atoms in one-dimensional harmonic traps. The effective potential is modeled by delta interaction. For this two-atom system, we have investigated quantum entanglement properties, such as von Neumann entropy and linear entropy for its ground state and excited states. Using a computational scheme that is different from previously employed, a total of the lowest 16 states are studied. Here we show the dependencies of entanglement properties under various interacting strengths. Comparisons for the ground state entanglement are made with earlier results in the literature. New results for the other 15 excited states are reported here.

scholarly journals Rényi and von Neumann entropies of thermal state in Generalized Uncertainty Principle-corrected harmonic oscillator

2021 ◽  
Vol 36 (35) ◽  
Author(s):  
MuSeong Kim ◽  
Mi-Ra Hwang ◽  
Eylee Jung ◽  
DaeKil Park
Keyword(s):  
Harmonic Oscillator ◽  
Uncertainty Principle ◽  
Temperature Region ◽  
Thermal State ◽  
Generalized Uncertainty Principle ◽  
Renyi Entropy ◽  
Rényi Entropy ◽  
Von Neumann Entropy ◽  
Large Temperature ◽  
Von Neumann

The Rényi and von Neumann entropies of thermal state in generalized uncertainty principle (GUP)-corrected single harmonic oscillator system are explicitly computed within the first order of GUP parameter [Formula: see text]. While the von Neumann entropy with [Formula: see text] exhibits a monotonically increasing behavior in external temperature, the nonzero GUP parameter makes a decreasing behavior at large temperature region. As a result, for the case of [Formula: see text], the von Neumann entropy is maximized at the finite temperature [Formula: see text]. The Rényi entropy [Formula: see text] with nonzero [Formula: see text] also exhibits similar behavior at large temperature region. In this region, the Rényi entropy exhibits a decreasing behavior with increasing temperature. The decreasing rate becomes larger when the order of the Rényi entropy is smaller.

“Non-locality”

2017 ◽  
Author(s):  
Richard Healey
Keyword(s):  
Quantum Theory ◽  
Quantum Entanglement ◽  
Quantum States ◽  
Entangled States ◽  
Entangled Quantum States ◽  
Action At A Distance ◽  
Insight Into ◽  
Non Locality

Quantum entanglement is popularly believed to give rise to spooky action at a distance of a kind that Einstein decisively rejected. Indeed, important recent experiments on systems assigned entangled states have been claimed to refute Einstein by exhibiting such spooky action. After reviewing two considerations in favor of this view I argue that quantum theory can be used to explain puzzling correlations correctly predicted by assignment of entangled quantum states with no such instantaneous action at a distance. We owe both considerations in favor of the view to arguments of John Bell. I present simplified forms of these arguments as well as a game that provides insight into the situation. The argument I give in response turns on a prescriptive view of quantum states that differs both from Dirac’s (as stated in Chapter 2) and Einstein’s.

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