Amorphous GexSe100−x (with x=10, 20 and 40 at%) alloys were prepared using the melt–quench technique. Two-dimensional Monte Carlo of the total pair distribution functions (MCGR) have been found and used to assemble the three-dimensional atomic configurations using the reverse Monte Carlo (RMC) method. The simulations are useful to compute the partial pair distribution functions and the partial structure factors of the studied glasses. The partial pair distribution functions indicate that the basic building units are GeSe4 and Ge2Se6 tetrahedral units in the Se-rich and Ge-rich glasses, respectively. Some of these tetrahedral units are connected by the homopolar units as confirmed by the bond angle distribution functions. The partial structure factors have shown that not only the homopolar Ge–Ge bonds, but also Se–Se bonds are behind the appearance of the first sharp diffraction peak (FSDP) in the total structure factor.

Amorphous GexSe100−x (with x=10, 20 and 40 at%) alloys were prepared using the melt–quench technique. Two-dimensional Monte Carlo of the total pair distribution functions (MCGR) have been found and used to assemble the three-dimensional atomic configurations using the reverse Monte Carlo (RMC) method. The simulations are useful to compute the partial pair distribution functions and the partial structure factors of the studied glasses. The partial pair distribution functions indicate that the basic building units are GeSe4 and Ge2Se6 tetrahedral units in the Se-rich and Ge-rich glasses, respectively. Some of these tetrahedral units are connected by the homopolar units as confirmed by the bond angle distribution functions. The partial structure factors have shown that not only the homopolar Ge–Ge bonds, but also Se–Se bonds are behind the appearance of the first sharp diffraction peak (FSDP) in the total structure factor.

Some aspects of the irreversible dynamics of a generalized Jaynes–
Cummings model are addressed. By working in the dressed-state
representation, it is possible to split the dynamics of the entanglement
and coherence. The exact solution of the master equation in
the case of a high-Q cavity with atomic decay is found. Effects of
the atomic spontaneous decay on the temporal evolution of partial
entropies of the atom or the field and the total entropy as a quantitative
measure entanglement are elucidated. The degree of entanglement,
through the sum of the negative eigenvalues of the
partially transposed density matrix and the negative mutual information
has been studied and compared with other measures.

Some aspects of the irreversible dynamics of a generalized Jaynes–
Cummings model are addressed. By working in the dressed-state
representation, it is possible to split the dynamics of the entanglement
and coherence. The exact solution of the master equation in
the case of a high-Q cavity with atomic decay is found. Effects of
the atomic spontaneous decay on the temporal evolution of partial
entropies of the atom or the field and the total entropy as a quantitative
measure entanglement are elucidated. The degree of entanglement,
through the sum of the negative eigenvalues of the
partially transposed density matrix and the negative mutual information
has been studied and compared with other measures.

An analytical solution is found for the master equation of a system described
by a nonlinear Jaynes–Cummings model, in the presence of nonlinear quantum
dissipation at zero temperature in the large detuning approximation. We study
the influence of nonlinear quantum dissipation on the output entanglement
dynamics of the atom–field system, considering the field to be initially in
SU(1, 1) coherent states. It is found that in the presence of the nonlinear
quantum dissipation, the amplitude of the output entanglement between the
field and the atom decreases with time, however the entanglement between the
field–atom system and the environment increases with time.

An analytical solution is found for the master equation of a system described
by a nonlinear Jaynes–Cummings model, in the presence of nonlinear quantum
dissipation at zero temperature in the large detuning approximation. We study
the influence of nonlinear quantum dissipation on the output entanglement
dynamics of the atom–field system, considering the field to be initially in
SU(1, 1) coherent states. It is found that in the presence of the nonlinear
quantum dissipation, the amplitude of the output entanglement between the
field and the atom decreases with time, however the entanglement between the
field–atom system and the environment increases with time.

MotivatedbyrecentexperimentswhereintheCooperboxcanbeusedtoprobethedecayofthe
resonatorsuperpositionstateduetoenvironmentaldecoherence.Wetheoreticallyinvestigatethe
dynamicsofentanglementandmixednessofasuperconductingqubitstronglycoupledtoacavityfield
inducedbyaphase-dampingreservoirgovernedbyamasterequation.Withaphase-damping,the
amountoftheentanglementandthemixednessoftheglobalsystemandoftheresonatorstateshave
invariantdynamicswhilephasedampinghasnoeffectonthedynamicofthedegreeofthemixedness
of theCooper-pairstate.

MotivatedbyrecentexperimentswhereintheCooperboxcanbeusedtoprobethedecayofthe
resonatorsuperpositionstateduetoenvironmentaldecoherence.Wetheoreticallyinvestigatethe
dynamicsofentanglementandmixednessofasuperconductingqubitstronglycoupledtoacavityfield
inducedbyaphase-dampingreservoirgovernedbyamasterequation.Withaphase-damping,the
amountoftheentanglementandthemixednessoftheglobalsystemandoftheresonatorstateshave
invariantdynamicswhilephasedampinghasnoeffectonthedynamicofthedegreeofthemixedness
of theCooper-pairstate.

A system of a two level atom interacting with a multi-photon single mode of electromagnetic field and damped with a phase reservoir is considered. The squeezed coherent state is taken as initial field state. The exact solution of the master equation in the case of a high-Q cavity is found. The effects of phase damping on the temporal evolution of some quantitative entanglement measures between the states of the system are investigated.

A system of a two level atom interacting with a multi-photon single mode of electromagnetic field and damped with a phase reservoir is considered. The squeezed coherent state is taken as initial field state. The exact solution of the master equation in the case of a high-Q cavity is found. The effects of phase damping on the temporal evolution of some quantitative entanglement measures between the states of the system are investigated.