Stochastic Description of Quantum Dissipative Dynamics
主 题: Stochastic Description of Quantum Dissipative Dynamics
时 间: 2013-12-03 16:00-17:00
地 点: 理科一号楼1114室
Upon employing the Hubbard-Stratonovich transformation or Ito calculus as well as the Girsanov transformation, the quantum dynamics of a dissipative system described by a system-plus-bath model is shown to satisfy a stochastic Liouville equation that might be regarded as the quantum analogue to the traditional Langevin equation.
The stochastic formulation can be used as a theoretical tool for deriving master equations for specific systems or developing approximations. It can also be employed as a practical technique for simulating dissipative dynamics numerically via a direct implementation or transforming to a deterministic algorithm a la hierarchical equations. It has been demonstrated that a mixed random-deterministic scheme taking both advantages of the random and deterministic treatments allows for the calculation of the zero-temperature dynamics of the dissipative two-state system with Ohmic dissipation. It is observed that for strong dissipation the population in the localized state obeys a simple rate dynamics and the time scale is proportional to the reciprocal of the cutoff frequency.