Non-Markovian Dynamics of Spin Squeezing Under Detuning Modulation

2017 ◽  
Vol 24 (01) ◽  
pp. 1750003
Author(s):  
Xing Xiao ◽  
Jia-Ju Wu ◽  
Wo-Jun Zhong ◽  
Yan-Ling Li
Keyword(s):  
Sudden Death ◽  
Open Systems ◽  
Spin Squeezing ◽  
Zero Temperature ◽  
Quantum Metrology ◽  
Markovian Dynamics ◽  
Long Time ◽  
Markovian Regime

The dynamics of spin squeezing of an ensemble of N separate spin-1/2 particles, each coupled to a zero-temperature non-Markovian reservoir have been investigated. We show that the initial spin squeezing could be prolonged for a long time by utilizing detuning modification. We further explore that the spin squeezing sudden death (SSSD) could be circumvented with the increasing of detuning. By comparison with the results in Markovian regime with detuning and those in non-Markovian regime without detuning, we conclude that the disappearance of SSSD and the robust preservation of spin squeezing should be attributed to the combination of detuning and non-Markovian effect. The present results may be of direct importance for quantum metrology in open systems.

Quantum correlations and coherence dynamics in qutrit–qutrit systems under mixed classical environmental noises

2017 ◽  
Vol 15 (06) ◽  
pp. 1750047 ◽  
Author(s):  
Tsamouo Tsokeng Arthur ◽  
Tchoffo Martin ◽  
Lukong Cornelius Fai
Keyword(s):  
Sudden Death ◽  
Quantum Discord ◽  
Quantum Correlations ◽  
Collective Effects ◽  
Markovian Environment ◽  
Dynamic Noise ◽  
Long Time ◽  
Noise Models ◽  
Markovian Regime ◽  
Static Noise

We investigate the dynamics of entanglement, quantum discord (QD) and state coherence in a bipartite and noninteracting spin-qutrits system under mixed classical noises. Specifically, the collective effects of static noise (SN) and random telegraphic noise (RTN) each being coupled with a marginal system, are analyzed. While the static noise models a non-Markovian environment, the dynamic noise can model both a Markovian or a non-Markovian environment, and both dynamics are studied. We show that quantum correlations and coherence may survive the noise degrading effects at sufficiently long time when the Markovian regime of the RTN is considered. Meanwhile, the opposite is found in the non-Markovian regime, wherein the nonmonotonic dynamics of quantum features avoid sudden death phenomena. However, the static noise is more fatal to the survival of quantum correlations and quantum state coherence as compared to the RTN.

THE COMPLETE TREATMENT OF THE TIME EVOLUTION IN THE CASE OF A DISCRETIZED ATOM-FIELD INTERACTION MODEL

2001 ◽  
Vol 15 (21) ◽  
pp. 883-894
Author(s):  
J. SEKE ◽  
A. V. SOLDATOV ◽  
N. N. BOGOLUBOV
Keyword(s):  
State Energy ◽  
Interaction Model ◽  
Time Interval ◽  
Short Time Interval ◽  
Field Interaction ◽  
Markovian Dynamics ◽  
Complete Treatment ◽  
Time Regime ◽  
Long Time ◽  
Short Time

The dynamics of a discretized atom-field interaction model with a physically relevant form factor is analyzed. It is shown that after some short time interval only a small fraction of eigenvalues and eigenstates (belonging to the close vicinity of the excited atomic state energy E = ω0/2) contributes to the nondecay probability amplitudes in the long-time regime, whereas the contribution of all other eigenstates and eigenvalues is negligible. Nevertheless, to describe correctly the non-Markovian dynamics in the short-time regime the contribution of all eigenstates and eigenvalues must be taken into account.

scholarly journals Effects of phase shift on bipartite and multipartite correlations of a spin chain under dephasing

Open Physics ◽  
2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Ai-Xi Chen ◽  
Jian-Song Zhang
Keyword(s):  
Steady State ◽  
Phase Shift ◽  
Analytical Solution ◽  
Spin Chain ◽  
Quantum Discord ◽  
Present Model ◽  
Spin Squeezing ◽  
Heisenberg Chain ◽  
Initial Correlations ◽  
Long Time

AbstractWe investigate the effects of phase shift on entanglement, quantum discord, geometric discord, and spinsqueezing of a Heisenberg chain under dephasing. An analytical solution of the present model is obtained. Our results show that the initial correlations of the spin chain could be partially stored for a long time in the presence of dephasing and the amount of steady state correlations can be adjusted via phase shift. Particularly, we find the effects of phase shift on quantum discord and geometric discord are not always the same, i.e., the increase of geometric discord does not always imply the increase of quantum discord. Then, we calculate the spin-squeezing of the spin chain and find that spin-squeezing first increases with time and then reaches a plateau. The amount of spin-squeezing can be controlled via phase shift.

scholarly journals Relative ordering in the radial evolution of solar wind turbulence: the S-Theorem approach

2011 ◽  
Vol 29 (12) ◽  
pp. 2317-2326 ◽  
Author(s):  
G. Consolini ◽  
P. De Michelis
Keyword(s):  
Solar Wind ◽  
Open Systems ◽  
Radial Distance ◽  
Slow Solar Wind ◽  
Time Interval ◽  
Turbulent Fluctuations ◽  
Long Time ◽  
Far From Equilibrium ◽  
Radial Evolution ◽  
Degree Of Order

Abstract. Over the past few decades scientists have shown growing interest in space plasma complexity and in understanding the turbulence in magnetospheric and interplanetary media. At the beginning of the 1980s, Yu. L. Klimontovich introduced a criterion, named S-Theorem, to evaluate the degree of order in far-from-equilibrium open systems, which applied to hydrodynamic turbulence showed that turbulence flows were more organized than laminar ones. Using the same theorem we have evaluated the variation of the degree of self-organization in both Alfvénic and non-Alfvénic turbulent fluctuations with the radial evolution during a long time interval characterized by a slow solar wind. This analysis seems to show that the radial evolution of turbulent fluctuations is accompanied by a decrease in the degree of order, suggesting that, in the case of slow solar wind, the turbulence decays with radial distance.

scholarly journals Spin squeezing in Bose—Einstein condensates: Limits imposed by decoherence and non-zero temperature

2011 ◽  
Vol 7 (1) ◽  
pp. 86-97 ◽  
Author(s):  
Alice Sinatra ◽  
Jean-Christophe Dornstetter ◽  
Yvan Castin
Keyword(s):  
Spin Squeezing ◽  
Zero Temperature ◽  
Bose Einstein

scholarly journals Robust quantum gates for open systems via optimal control: Markovian versus non-Markovian dynamics

2012 ◽  
Vol 14 (7) ◽  
pp. 073023 ◽  
Author(s):  
Frederik F Floether ◽  
Pierre de Fouquieres ◽  
Sophie G Schirmer
Keyword(s):  
Optimal Control ◽  
Open Systems ◽  
Quantum Gates ◽  
Markovian Dynamics

scholarly journals Quantum Metrology in Open Systems: Dissipative Cramér-Rao Bound

2014 ◽  
Vol 112 (12) ◽  
Author(s):  
S. Alipour ◽  
M. Mehboudi ◽  
A. T. Rezakhani
Keyword(s):  
Open Systems ◽  
Quantum Metrology ◽  
Cramer Rao Bound

scholarly journals Squeezing metrology: a unified framework

Quantum ◽  
2020 ◽  
Vol 4 ◽  
pp. 292
Author(s):  
Lorenzo Maccone ◽  
Alberto Riccardi
Keyword(s):  
Central Limit Theorem ◽  
Limit Theorem ◽  
General Theory ◽  
Spin Squeezing ◽  
Quantum Systems ◽  
Quantum Metrology ◽  
Unified Framework ◽  
The Central Limit Theorem ◽  
Arbitrary Quantum ◽  
Classical Strategy

Quantum metrology theory has up to now focused on the resolution gains obtainable thanks to the entanglement among N probes. Typically, a quadratic gain in resolution is achievable, going from the 1/N of the central limit theorem to the 1/N of the Heisenberg bound. Here we focus instead on quantum squeezing and provide a unified framework for metrology with squeezing, showing that, similarly, one can generally attain a quadratic gain when comparing the resolution achievable by a squeezed probe to the best N-probe classical strategy achievable with the same energy. Namely, here we give a quantification of the Heisenberg squeezing bound for arbitrary estimation strategies that employ squeezing. Our theory recovers known results (e.g. in quantum optics and spin squeezing), but it uses the general theory of squeezing and holds for arbitrary quantum systems.

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