scholarly journals Revisiting the Quantum Open System Dynamics of Central Spin Model

Quanta ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 55-64
Author(s):  
Samyadeb Bhattacharya ◽  
Subhashish Banerjee
Keyword(s):  
System Dynamics ◽  
Master Equation ◽  
Open System ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Spin Model ◽  
Open Quantum ◽  
Spin Bath ◽  
Quantum Open System ◽  
Kraus Operators

In this work, we revisit the theory of open quantum systems from the perspective of fermionic baths. Specifically, we concentrate on the dynamics of a central spin half particle interacting with a spin bath. We have calculated the exact reduced dynamics of the central spin and constructed the Kraus operators in relation to that. Further, the exact Lindblad type canonical master equation corresponding to the reduced dynamics is constructed. We have also briefly touched upon the aspect of non-Markovianity from the backdrop of the reduced dynamics of the central spin.Quanta 2021; 10: 55–64.

scholarly journals Adiabatically steered open quantum systems: Master equation and optimal phase

2010 ◽  
Vol 82 (6) ◽  
Author(s):  
J. Salmilehto ◽  
P. Solinas ◽  
J. Ankerhold ◽  
M. Möttönen
Keyword(s):  
Master Equation ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Open Quantum

FEEDBACK IN OPEN QUANTUM SYSTEMS

1995 ◽  
Vol 09 (11n12) ◽  
pp. 629-654 ◽  
Author(s):  
H. M. WISEMAN
Keyword(s):  
System Dynamics ◽  
Feedback Loop ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Feedback Mechanism ◽  
The Other ◽  
Langevin Equations ◽  
Quantum Trajectories ◽  
Classical Counterpart ◽  
Open Quantum

Open quantum systems continually lose information to their surroundings. In some cases this information can be readily retrieved from the environment and put to good use by engineering a feedback loop to control the system dynamics. Two cases are distinguished: one where the feedback mechanism involves a measurement of the environment, and the other where no measurement is made. It is shown that the latter case can always replicate the former, but not vice versa. This emphasizes the quantum nature of the information being fed back. Two approaches are used to describe the feedback: quantum trajectories (which apply only for feedback based on measurement) and quantum Langevin equations (which can be used in either case), and the results are shown to be equivalent. The obvious applications for the theory are in quantum optics, where the information is lost by radiation damping and can be retrieved by photodetection. A few examples are discussed, one of which is particularly interesting as it has no classical counterpart.

scholarly journals Post-Markov master equation for the dynamics of open quantum systems

2000 ◽  
Vol 265 (5-6) ◽  
pp. 331-336 ◽  
Author(s):  
Ting Yu ◽  
Lajos Diósi ◽  
Nicolas Gisin ◽  
Walter T. Strunz
Keyword(s):  
Master Equation ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Open Quantum ◽  
Markov Master Equation

NON-MARKOVIAN OPEN QUANTUM SYSTEMS: SYSTEM–ENVIRONMENT CORRELATIONS IN DYNAMICAL MAPS

2011 ◽  
Vol 09 (07n08) ◽  
pp. 1617-1634 ◽  
Author(s):  
CÉSAR A. RODRÍGUEZ-ROSARIO ◽  
E. C. G. SUDARSHAN
Keyword(s):  
Master Equation ◽  
Quantum Discord ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Complete Positivity ◽  
System Environment ◽  
Open Quantum ◽  
Mathematical Properties ◽  
Classical Correlations ◽  
The Relationship

We construct a non-Markovian dynamical map that accounts for systems correlated to the environment. We refer to it as a canonical dynamical map, which forms an evolution family. The relationship between inverse maps and correlations with the environment is established. The mathematical properties of complete positivity is related to classical correlations, according to quantum discord, between the system and the environment. A generalized non-Markovian master equation is derived from the canonical dynamical map.

scholarly journals On non-Markovian Time Evolution in Open Quantum Systems

2007 ◽  
Vol 14 (03) ◽  
pp. 265-274 ◽  
Author(s):  
Andrzej Kossakowski ◽  
Rolando Rebolledo
Keyword(s):  
Time Evolution ◽  
Open System ◽  
Open Quantum Systems ◽  
Vacuum State ◽  
Quantum Systems ◽  
Initial State ◽  
Completely Positive ◽  
Open Quantum

Non-Markovian reduced dynamics of an open system is investigated. In the case when the initial state of the reservoir is the vacuum state, an approximation is introduced which makes it possible to construct a reduced dynamics which is completely positive.

scholarly journals Degradation and Protection of Entanglement in Open Quantum Systems †

Proceedings ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 40
Author(s):  
Antonella Pasquale
Keyword(s):  
System Dynamics ◽  
Quantum Computation ◽  
Continuous Time ◽  
Noise Level ◽  
Quantum Communication ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Post Processing ◽  
Open Quantum ◽  
Time Description

The distribution of entangled quantum systems among the nodes of a network is a key task at the basis of the development of quantum technologies, e.g., quantum communication, quantum computation, etc. Many efforts have been devoted to identify strategies, based on pre- and post-processing operations or decoherence-free subspaces, to prevent the deterioration of such exotic correlations. However, all these approaches loose their usefulness when the noise level affecting the system surpasses a certain minimal threshold that leads to an entanglement-breaking dynamics. Here we attack this problem in the context of discrete- and continuous-time description of the system dynamics, providing some explicit examples in the context of qubit channels.

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