Rapid and slow decoherence in conjunction with dissipation in a system of two-level atoms

Abstract

We investigate the time evolution of a superposition of macroscopically distinct quantum states in a system of two-level atoms interacting with a thermal environment of photon modes. We show that the atomic coherent states are robust against decoherence, therefore we call their superpositions atomic Schrödinger cat states. The initial fast regime of the time evolution is associated with the process of decoherence, and it is directed towards the statistical mixture of the constituent coherent states of the original state for most of the initial conditions. However, certain superpositions, called symmetric, exhibit exceptionally slow decoherence. By introducing a new measure, we generalize the usual decoherence scheme regarding the evolution of the state to account also for the symmetric case. To stress the fact that the environment preserves symmetric superpositions much longer than the other ones,we present Wigner function images of the decoherence of a suitably oriented four component cat state.

9 pages, 6 figures. High quality figures can be downloaded from http://www.jate.u-szeged.hu/~benedict/. To appear in Phys. Rev. A, March 2001

Cited by in corpus (10)

• Relaxation of a two-level system strongly coupled to a reservoir: Anomalously slow decoherence
• Surface-hopping dynamics and decoherence with quantum equilibrium structure
• Decoherence of molecular wave packets in an anharmonic potential
• Stability of stationary solutions of the Schrodinger-Langevin equation
• Preparation of decoherence-free, subradiant states in a cavity
• Coherent states and global entanglement in an N qubit system
• Dynamics of periodic anticrossings: Decoherence, pointer states and hysteresis curves
• Quantum decoherence in the rotation of small molecules
• Global entanglement and coherent states in an N-partite system
• Stationary entanglement in N-atom subradiant degenerate cascade systems