On the interaction time evaluation

Denis Tolkunov, Vladimir Privman A

A short-time approximation is developed for system-environmental bath mode interactions involving a general non-Hermitian system operator $\ensuremath{\Lambda}$ and its conjugate ${\ensuremath{\Lambda}}^{\ifmmode\dagger\else\textdagger\fi{}}$ in order to evaluate the onset of decoherence at low temperatures in quantum systems interacting with the environment. The developed approach is complementary to Markovian approximations and appropriate for the evaluation of quantum computing schemes. An example of a spin system coupled to a bosonic heat bath via $\ensuremath{\Lambda}\ensuremath{\propto}{\ensuremath{\sigma}}_{\ensuremath{-}}$ is worked out in detail.

É. Papp

Vladimir Privman A, Denis Tolkunov

We review our recent results on short time approximations, with emphasis on applications for which the system-environment interactions involve a general non-Hermitian system operator and its conjugate. We evaluate the onset of decoherence at low temperatures in open quantum systems. The developed approach is complementary to Markovian approximations and appropriate for evaluation of quantum computing schemes. Example of a spin system coupled to a bosonic heat bath is discussed.

Aide, Satoru

John C. Inkson

A. Krügel, Luis Roa, C. Saavedra

We study the stability of the coherence of a state of a quantum system under the effect of an interaction with another quantum system at short time. We find an expression for evaluating the order of magnitude of the time scale for the onset of instability as a function of the initial state of both involved systems and of the sort of interaction between them. As an application we study the spin-boson interaction in the dispersive interaction regime, driven by a classical field. We find, for this model, that the behavior of the time scale for the onset of instability, with respect to the boson bath temperature, changes depending on the intensity of the classical field.