Crossover Time in Quantum Boson and Spin Systems

The authors compare classical and quantum dynamics in the quasiclassical region of parameters and under the condition of unstable (chaotic) classical behavior. They estimate the characteristic time-scale at which classical and quantum solutions start to differ significantly. The method is based on exact equations for time-dependent expectation values in boson and spin coherent states, and applies to rather general Hamiltonians with many degrees of freedom. The authors develop a consistent dynamical theory for quantum nonintegrable Hamiltonians and provide explicit examples of classical-quantum crossover-time , a very common and fundamental phenomenon in quantum nonintegrable systems. This book can be recommended to graduate students and to specialists.

This monograph compares classical and quantum dynamics for unstable (chaotic) systems. Characteristic times for divergence of classical and quantum solutions are estimated, and examples of classical-quantum "crossover-times" are provided. The book can be recommended to graduate students and to specialists. This monograph compares classical and quantum dynamics for unstable (chaotic) systems. Characteristic times for divergence of classical and quantum solutions are estimated, and examples of classical-quantum "crossover-times" are provided. The book can be recommended to graduate students and to specialists.