Quantum to Classical Transition by a Classically Small Interaction

Wen-Lei Zhao, Jie Quan-Lin, Bo Zhou

We investigate the quantum-classical transition of a kicked rotor (KR) under perturbation by a second one. The influence of such a chaotic KR makes decoherence of the first one, resulting in the emergence of classical diffusion from its quantum dynamics. Such quantum-classical transition persists by decreasing the effective Planck's constant ℏ, and at the same time, decreasing the mass of the second KR and the interaction strength proportionally. In the limit of ħ → 0, due to vanishing small mass and interaction, the second KR has almost no effect on the classical dynamics of the first one. We demonstrate this via two different coupling potentials.

Maximilian Andreas Schlosshauer-Selbach

Wen-Lei Zhao, Jianzhong Wang, Dou Fu-Quan

Via a system of two kicked particles that are coupled in an infinite square well, we numerically show that the interaction with a particle of very small mass is able to lead to a quantum-to-classical transition on condition that the corresponding classical dynamics is almost unaffected. With the decrease of the mass of one of the particles, its effect on the classical dynamics of the other one decreases. Such an effect is even negligible if the mass of the particle is small enough. The classically chaotic dynamics of this small particle is effective for promoting the decoherence of the heavy particle. Therefore its quantum behavior exhibits the transition from the dynamical localization to the classically chaotic diffusion with the decrease of the effective Planck's constant ħ. Under the perturbation from the small particle, the linear entropy is rapidly saturated as time passes by. With the decrease of ħ, the time-averaged linear entropy exponentially increases from zero to almost unity.

Wen-Lei Zhao, Quanlin Jie

We investigate the quantum to classical transition induced by two-particle interaction via a system of periodically kicked particles. The classical dynamics of particle 1 is almost unaffected in condition that its mass is much larger than that of particle 2. Interestingly, such classically weak influence leads to the quantum to classical transition of the dynamical behavior of particle 1. Namely, the quantum diffusion of this particle undergoes the transition from dynamical localization to the classically chaotic diffusion with the decrease of the effective Planck constant ℏ eff. The behind physics is due to the growth of entanglement in the system. The classically very weak interaction leads to the exponential decay of purity in condition that the classical dynamics of external degrees freedom is strongly chaotic.

Maximilian Schlosshauer