scholarly journals An investigation of some quantum correlations of Dirac fields in noninertial frames

2019 ◽  
Vol 97 (1) ◽  
pp. 42-50
Author(s):  
Mohammad Bagher Arjmandi
Keyword(s):  
Single Mode ◽  
Quantum Correlations ◽  
Initial State ◽  
Dirac Fields ◽  
Acceleration Parameter ◽  
Entanglement Of Formation ◽  
Single Mode Approximation ◽  
Accelerated Observers ◽  
Werner States

In this paper, some concepts of quantum correlations, such as one-way quantum deficit, purity, and entanglement of formation are investigated between the modes of Dirac fields in noninertial frames. We consider two bipartite divisions of a tripartite system constructed by initial Werner states, which is shared between two relatively accelerated observers. The degradation of these quantum correlations is shown when the acceleration parameter increases. However, a nonzero amount of correlations survives even at infinite acceleration limit. Furthermore, we study the inevitable influence of mixedness factor of initial state on the quantum correlations behaviour. Finally, we review our calculation beyond single-mode approximation and point out some differences and similarities between the two regimes.

Chaos Control in Single Mode Approximation of T-AFM Systems Using Nonlinear Delayed Feedback Based on Sliding Mode Control

2007 ◽  
Author(s):  
Hoda Sadeghian ◽  
Mehdi Tabe Arjmand ◽  
Hassan Salarieh ◽  
Aria Alasty
Keyword(s):  
Feedback Control ◽  
High Performance ◽  
Sliding Mode ◽  
Chaotic Behavior ◽  
Single Mode ◽  
Delayed Feedback ◽  
Delayed Feedback Control ◽  
Model Parameters ◽  
Unstable Periodic Orbits ◽  
Single Mode Approximation

The taping mode Atomic Force Microscopic (T-AFM) can be properly described by a sinusoidal excitation of its base and nonlinear potential interaction with sample. Thus the cantilever may cause chaotic behavior which decreases the performance of the sample topography. In this paper a nonlinear delayed feedback control is proposed to control chaos in a single mode approximation of a T-AFM system. Assuming model parameters uncertainties, the first order Unstable Periodic Orbits (UPOs) of the system is stabilized using the sliding nonlinear delayed feedback control. The effectiveness of the presented methods is numerically verified and the results show the high performance of the controller.

Excitation of superharmonics by internal modes in non-uniformly stratified fluid

2016 ◽  
Vol 793 ◽  
pp. 335-352 ◽  
Author(s):  
Bruce R. Sutherland
Keyword(s):  
Single Mode ◽  
Stratified Fluid ◽  
Buoyancy Frequency ◽  
Nonlinear Interactions ◽  
Initial State ◽  
Weakly Nonlinear ◽  
Resonant Wave ◽  
Vertical Scale ◽  
Scale Structures ◽  
Parametric Subharmonic Instability

Theory and numerical simulations show that the nonlinear self-interaction of internal modes in non-uniform stratification results in energy being transferred to superharmonic disturbances forced at twice the horizontal wavenumber and frequency of the parent mode. These disturbances are not in themselves a single mode, but a superposition of modes such that the disturbance amplitude is largest where the change in the background buoyancy frequency with depth is largest. Through weakly nonlinear interactions with the parent mode, the disturbances evolve to develop vertical-scale structures that distort and modulate the parent mode. Because pure resonant wave triads do not exist in non-uniformly stratified fluid, parametric subharmonic instability (PSI) is not evident even though noise is superimposed upon the initial state. The results suggest a new mechanism for energy transfer to dissipative scales (from large to small vertical scale and with frequencies larger and smaller than that of the parent mode) through forcing superharmonic rather than subharmonic disturbances.

scholarly journals Generation of Quantum Correlations in Bipartite Gaussian Open Quantum Systems

2018 ◽  
Vol 173 ◽  
pp. 01006 ◽  
Author(s):  
Aurelian Isar
Keyword(s):  
Open Systems ◽  
Thermal Environment ◽  
Open Quantum Systems ◽  
Quantum Correlations ◽  
Quantum Systems ◽  
Thermal Bath ◽  
Initial State ◽  
Entanglement Generation ◽  
Strength Of Interaction ◽  
Zero Values

We describe the generation of quantum correlations (entanglement, discord and steering) in a system composed of two coupled non-resonant bosonic modes immersed in a common thermal reservoir, in the framework of the theory of open systems. We show that for separable initial squeezed thermal states entanglement generation may take place, for definite values of squeezing parameter, average photon numbers, temperature of the thermal bath, dissipation constant and strength of interaction between the two bosonic modes. We also show that for initial uni-modal squeezed states Gaussian discord can be generated for all non-zero values of the strength of interaction between the modes. Likewise, for an initial separable state, a generation of Gaussian steering may take place temporarily, for definite values of the parameters characterizing the initial state and the thermal environment, and the strength of coupling between the two modes.

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