Beyond Fermi's golden rule with the statistical Jacobi approximation
Beyond Fermi's golden rule with the statistical Jacobi approximation
Many problems in quantum dynamics can be cast as the decay of a single quantum state into a continuum. The time-dependent overlap with the initial state, called the fidelity, characterizes this decay. We derive an analytic expression for the fidelity after a quench to an ergodic Hamiltonian. The expression is …