scholarly journals Influence of the Coupling between Two Qubits in an Open Coherent Cavity: Nonclassical Information via Quasi-Probability Distributions

Entropy ◽  
2019 ◽  
Vol 21 (12) ◽  
pp. 1137 ◽  
Author(s):  
Abdel-Baset A. Mohamed ◽  
Hichem Eleuch ◽  
Abdel-Shafy F. Obada
Keyword(s):  
Quantum Coherence ◽  
Probability Distributions ◽  
Microwave Cavity ◽  
Wehrl Entropy ◽  
Intrinsic Decoherence ◽  
Probability Functions ◽  
Decoherence Rate ◽  
Two Level Systems ◽  
Q Function ◽  
Nonclassical Information

In this paper, we investigate the dynamics of two coupled two-level systems (or qubits) that are resonantly interacting with a microwave cavity. We examine the effects of the intrinsic decoherence rate and the coupling between the two qubits on the non-classicality of different system partitions via quasi-probability functions. New definitions for the partial Q-function and its Wehrl entropy are used to investigate the information and the quantum coherence of the phase space. The amount of the quantum coherence and non-classicality can be appropriately tuned by suitably adopting the rates of the intrinsic-decoherence and the coupling between the two qubits. The intrinsic decoherence has a pronounced effect on the negativity and the positivity of the Wigner function. The coupling between the two qubits can control the negativity and positivity of the quasi-probability functions.

scholarly journals Quasi-probability information in a coupled two-qubit system interacting non-linearly with a coherent cavity under intrinsic decoherence

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Abdel-Baset A. Mohamed ◽  
Hichem Eleuch
Keyword(s):  
Phase Space ◽  
Quantum Coherence ◽  
Coupling Constants ◽  
Light Quantum ◽  
Wehrl Entropy ◽  
Intrinsic Decoherence ◽  
Highly Sensitive ◽  
Qubit System ◽  
Probability Information ◽  
Q Function

AbstractWe explore the phase space quantum effects, quantum coherence and non-classicality, for two coupled identical qubits with intrinsic decoherence. The two qubits are in a nonlinear interaction with a quantum field via an intensity-dependent coupling. We investigate the non-classicality via the Wigner functions. We also study the phase space information and the quantum coherence via the Q-function, Wehrl density, and Wehrl entropy. It is found that the robustness of the non-classicality for the superposition of coherent states, is highly sensitive to the coupling constants. The phase space quantum information and the matter-light quantum coherence can be controlled by the two-qubit coupling, initial cavity-field and the intrinsic decoherence.

Mixture of Two LindleyProbability Models And Application In Reliability

2015 ◽  
Vol 4 (2) ◽  
Author(s):  
Ehtesham Husain ◽  
Masood Ul Haq
Keyword(s):  
Distribution Function ◽  
Probability Distribution ◽  
Mixture Model ◽  
Mathematical Expectation ◽  
Probability Distributions ◽  
Reliability Function ◽  
Probability Models ◽  
Probability Functions ◽  
Two Component ◽  
In Series

<span>Mixture probability models are developed in general<br /><span>from Uni variate Probability functions (say)<br /><span><em>g</em><span>1 <span>(<span><em>x</em><span>) <span><em>and g</em><span>2 <span>(<span><em>x</em><span>) <span>. The mixture of these two is defined by<br /><span><em>f</em><span>(<span><em>x</em><span>)  <span><em>p</em><span>.<span><em>g</em><span>1 <span>(<span><em>x</em><span>)  (1  <span><em>p</em><span>) <span><em>g</em><span>2 <span>(<span><em>x</em><span>) <span>where “p” is the mixing<br /><span>ratio. The function that we have in the present paper is the<br /><span>Mixture of two Lindley probability distributions, each of<br /><span>which is having a different parameter. Lindley models are<br /><span>also useful for data showing decaying trends. The properties<br /><span>of Lindley probability distribution that have been shown<br /><span>are Mathematical Expectation, Second Moment, and the<br /><span>Distribution Function. An application of the Mixture Model<br /><span>which has been derived in the present research , has been<br /><span>applied to the Reliability function , in a two component<br /><span>system , when the components are connected in series. The<br /><span>Reliability of the discussed system is compared with<br /><span>reliability values when the Lindley probabilities in the same<br /><span>system , are independent.</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span><br /><br class="Apple-interchange-newline" /></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

scholarly journals The Anisotropic Glassy Properties of Decagonal Quasicrystals

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Dragoş-Victor Anghel ◽  
Dmitry V. Churochkin
Keyword(s):  
Strain Field ◽  
Sound Absorption ◽  
Probability Distributions ◽  
Symmetric Tensor ◽  
Coupling Constants ◽  
Extended Version ◽  
Tunneling Model ◽  
Decagonal Quasicrystals ◽  
Symmetry Properties ◽  
Two Level Systems

We use an extended version of the standard tunneling model to explain the anisotropic sound absorption in decagonal quasicrystals. The glassy properties are determined by an ensemble of two level systems (TLSs), arbitrarily oriented. The TLS is characterized by a 3 × 3 symmetric tensor, [T], which couples to the strain field, [S], through a 3 × 3 × 3 × 3 tensor of coupling constants, [R]. The structure of [R] reflects the symmetry of the quasicrystal. We also analyze the probability distributions of the elements of [T] in this particular model for a better understanding of the characteristics of “isotropic” and “anisotropic” distributions of the ensemble of TLSs. We observe that the distribution of the elements is neither simple nor intuitive and therefore it is difficult to guess ita priory, using qualitative arguments based on the symmetry properties.

scholarly journals Measurement Induced Synthesis of Coherent Quantum Batteries

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mariia Gumberidze ◽  
Michal Kolář ◽  
Radim Filip
Keyword(s):  
Steady State ◽  
Numerical Optimization ◽  
Quantum Coherence ◽  
Measurement Process ◽  
Coherent System ◽  
Cold Environment ◽  
Maxwell Demon ◽  
Two Level Systems ◽  
Quantum Technology ◽  
Coherent Quantum

AbstractQuantum coherence represented by a superposition of energy eigenstates is, together with energy, an important resource for quantum technology and thermodynamics. Energy and quantum coherence however, can be complementary. The increase of energy can reduce quantum coherence and vice versa. Recently, it was realized that steady-state quantum coherence could be autonomously harnessed from a cold environment. We propose a conditional synthesis of N independent two-level systems (TLS) with partial quantum coherence obtained from an environment to one coherent system using a measurement able to increase both energy and coherence simultaneously. The measurement process acts here as a Maxwell demon synthesizing the coherent energy of individual TLS to one large coherent quantum battery. The measurement process described by POVM elements is diagonal in energy representation and, therefore, it does not project on states with quantum coherence at all. We discuss various strategies and their efficiency to reach large coherent energy of the battery. After numerical optimization and proof-of-principle tests, it opens way to feasible repeat-until-success synthesis of coherent quantum batteries from steady-state autonomous coherence.

ATOMIC WEHRL ENTROPY OF A SINGLE QUBIT SYSTEM

2011 ◽  
Vol 09 (03) ◽  
pp. 967-979 ◽  
Author(s):  
S. ABDEL-KHALEK ◽  
H. F. ABDEL-HAMEED ◽  
M. ABDEL-ATY
Keyword(s):  
Hilbert Space ◽  
Density Operator ◽  
Center Of Mass ◽  
Level System ◽  
Initial State ◽  
Wehrl Entropy ◽  
Trapped Ion ◽  
Single Qubit ◽  
Qubit System ◽  
Q Function

We propose the use of atomic Wehrl entropy associated to the reduced atomic density operator as an entanglement indicator of bipartite systems. This is applied to a two-level system (one single harmonically trapped ion) by taking into account the linear center-of-mass-motional degree of freedom. Detailed analytical and explicit expressions are given, taking into account different configurations. The results show the important roles played by the laser phase and initial state setting in the evolution of the atomic Q-function, atomic Wehrl entropy and marginal atomic Q-function. Our procedure of using atomic Wehrl entropy may be applied to a system with Hilbert space of high dimension.

scholarly journals Quantum Fisher Information and Bures Distance Correlations of Coupled Two Charge-Qubits Inside a Coherent Cavity with the Intrinsic Decoherence

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 352
Author(s):  
Abdel-Baset A. Mohamed ◽  
Eied. M. Khalil ◽  
Mahmoud M. Selim ◽  
Hichem Eleuch
Keyword(s):  
Fisher Information ◽  
Coherent States ◽  
Quantum Fisher Information ◽  
Quantum Correlations ◽  
Freezing Behavior ◽  
Intrinsic Decoherence ◽  
Decoherence Rate ◽  
Local Quantum ◽  
Decoherence Effect ◽  
Bures Distance

The dynamics of two charged qubits containing Josephson Junctions inside a cavity are investigated under the intrinsic decoherence effect. New types of quantum correlations via local quantum Fisher information and Bures distance norm are explored. We show that we can control the quantum correlations robustness by the intrinsic decoherence rate, the qubit-qubit coupling as well as by the initial coherent states superposition. The phenomenon of sudden changes and the freezing behavior for the local quantum Fisher information are sensitive to the initial coherent state superposition and the intrinsic decoherence.

scholarly journals Nonclassical Effects Based on Husimi Distributions in Two Open Cavities Linked by an Optical Waveguide

Entropy ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 767
Author(s):  
Abdel-Baset A. Mohamed ◽  
Hichem Eleuch
Keyword(s):  
Phase Space ◽  
Quantum Wells ◽  
Optical Waveguide ◽  
Quantum Coherence ◽  
Physical Parameters ◽  
Medium Density ◽  
Wehrl Entropy ◽  
Optical Medium ◽  
Optical Susceptibility ◽  
Open Cavities

Nonclassical effects are investigated in a system formed by two quantum wells, each of which is inside an open cavity. The cavities are spatially separated, linked by a fiber, and filled with a linear optical medium. Based on Husimi distributions (HDs) and Wehrl entropy, we explore the effects of the physical parameters on the generation and the robustness of the mixedness and HD information in the phase space. The generated quantum coherence and the HD information depend crucially on the cavity-exciton and fiber cavity couplings as well as on the optical medium density. The HD information and purity are lost due to the dissipation. This loss may be inhibited by increasing the optical susceptibility as well as the couplings of the exciton-cavity and the fiber-cavity. These parameters control the regularity, amplitudes, and frequencies of the generated mixedness.

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