Level Dynamics

Fritz Haake

Jie Jie, QLWang, SJWei

From level dynamics, we show that when two levels come to an avoided From level dynamics, we show that when two levels come to an avoided

Perry R. Rice

Artur Maksymov, Piotr Sierant, Jakub Zakrzewski

The level dynamics across the many-body localization transition is examined for XXZ spin model with a random magnetic field. We compare different scenarios of parameter-dependent motion in the system and consider measures such as level velocities, curvatures, as well as their fidelity susceptibilities. Studying the ergodic phase of the model we find that the level dynamics does not reveal the commonly believed universal behavior after rescaling the curvatures by the level velocity variance. At the same time, distributions of level curvatures and fidelity susceptibilities coincide with properly rescaled distributions for Gaussian orthogonal ensemble of random matrices. Profound differences exist depending on way the level dynamics is imposed in the many-body localized phase of the model in which the level dynamics can be understood with the help of local integrals of motion.

Alexander V. Gorokhov, Ilya E. Sinaiski

It is considered dynamics of two identical two-level atoms in non-ideal cavity. Using approach developed before by us for case of one two-level atom, analytical expression for density matrix of the system is presented. Dynamics of level populations, mean number of photons and correlation function for photons are considered. Using Peres-Horodecki criteria exact expression for entanglement dynamics of two identical two-level atoms in cavity is given. Influence of detuning and damping constants are considered.

Perry R. Rice