ESTIMATION OF PURITY FOR A QUANTUM HARMONIC OSCILLATOR INITIALLY PREPARED IN A DISPLACED THERMAL STATE

2012 ◽  
Vol 10 (08) ◽  
pp. 1241015 ◽  
Author(s):  
MATTEO BRUNELLI ◽  
STEFANO OLIVARES ◽  
MAURO PATERNOSTRO ◽  
MATTEO G. A. PARIS
Keyword(s):  
Harmonic Oscillator ◽  
Fisher Information ◽  
Thermal State ◽  
Quantum Fisher Information ◽  
Optimal Estimation ◽  
Quantum Oscillator ◽  
Quantum Harmonic Oscillator ◽  
Rotating Wave Approximation ◽  
Wave Approximation ◽  
Rotating Wave

We address the estimation of purity for a quantum oscillator initially prepared in a displaced thermal state and probed by a suitably prepared qubit interacting with the oscillator via Jaynes–Cummings Hamiltonian without the rotating-wave approximation. We evaluate the quantum Fisher information (QFI) and show that optimal estimation of purity can be achieved by measuring the population of the qubit after a properly chosen interaction time. We also address the estimation of purity at fixed total energy and show that the corresponding precision is independent of the presence of a coherent amplitude.

The Dicke model in quantum optics: Dicke model revisited

2011 ◽  
Vol 369 (1939) ◽  
pp. 1137-1155 ◽  
Author(s):  
Barry M. Garraway
Keyword(s):  
Phase Transitions ◽  
Quantum Optics ◽  
Short Review ◽  
Quantum Oscillator ◽  
Zero Temperature ◽  
Rotating Wave Approximation ◽  
Wave Approximation ◽  
Recent Developments ◽  
Rotating Wave ◽  
Dicke Model

A short review of recent developments of the Dicke model in quantum optics is presented. The focus is on the model in a cavity at zero temperature and in the rotating wave approximation. Topics discussed include spectroscopic structures, the giant quantum oscillator, entanglement and phase transitions.

Influence of the counter-rotating terms on the quantum dynamics of the damped harmonic oscillator in a deformed bath

2019 ◽  
Vol 33 (13) ◽  
pp. 1950126
Author(s):  
Mohsen Daeimohammad
Keyword(s):  
Correlation Function ◽  
Harmonic Oscillator ◽  
Diffusion Coefficients ◽  
Quantum Dynamics ◽  
Equation Of Motion ◽  
Rotating Wave Approximation ◽  
Wave Approximation ◽  
Damped Harmonic Oscillator ◽  
Rotating Wave ◽  
Damped Oscillator

The aim of the present study is to investigate the effect of the counter-rotating terms on the quantum dynamics of a harmonic oscillator in the presence of a deformed bath. We first obtain the Langevin equation of motion for damped oscillator with and without the rotating-wave approximation (RWA). Then, we study the effect of the counter-rotating terms on the diffusion coefficients. Then, we obtain the equation of motion for the harmonic oscillator correlation function with and without the RWA. Finally, we investigate the influence of the counter-rotating terms on the oscillator correlation function.

scholarly journals Bistable dynamics beyond rotating wave approximation

2014 ◽  
Vol 23 (02) ◽  
pp. 1450019 ◽  
Author(s):  
Y. A. Sharaby ◽  
S. Lynch ◽  
A. Joshi ◽  
S. S. Hassan
Keyword(s):  
Ring Cavity ◽  
Dynamical Behavior ◽  
Single Mode ◽  
Unstable State ◽  
Nonlinear Dynamical ◽  
Rotating Wave Approximation ◽  
Wave Approximation ◽  
Atomic Medium ◽  
Bistable Dynamics ◽  
Rotating Wave

In this paper, we investigate the nonlinear dynamical behavior of dispersive optical bistability (OB) for a homogeneously broadened two-level atomic medium interacting with a single mode of the ring cavity without invoking the rotating wave approximation (RWA). The periodic oscillations (self-pulsing) and chaos of the unstable state of the OB curve is affected by the counter rotating terms through the appearance of spikes during its periods. Further, the bifurcation with atomic detuning, within and outside the RWA, shows that the OB system can be converted from a chaotic system to self-pulsing system and vice-versa.

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