Abstract
Decoherence causes entropy increase that can be quantified using, e.g., the purity . When the Hamiltonian of a quantum system is perturbed, its sensitivity to such perturbation can be measured by the Loschmidt echo . It is given by the squared overlap between the perturbed and unperturbed state. We describe the relation between the temporal behavior of and the average . In this way we show that the decay of the Loschmidt echo can be analyzed using tools developed in the study of decoherence. In particular, for systems with a classically chaotic Hamiltonian the decay of and has a regime where it is dominated by the Lyapunov exponents.
- Received 20 June 2003
DOI:https://doi.org/10.1103/PhysRevLett.91.210403
©2003 American Physical Society