Decoherence and dissipation in a molecular system coupled to an environment: An application of semiclassical hybrid dynamics

Abstract

Applying the recently developed semiclassical hybrid dynamics [Grossmann, J. Chem. Phys. 125, 014111 (2006)], we study the decay of interference patterns in the reduced density as well as of the purity in a Morse oscillator test system due to the interaction with a finite harmonic bath at zero temperature. In the case that the bath mimics a continuous Ohmic spectral density, in addition to the quantum classical transition induced by the interaction with the environment, we corroborate the existence of a blueshift due to the bath coupling, predicted by Pollak [Phys. Rev. A 33, 4244 (1986)]. Furthermore, the decoherence dynamics of cat states is confirmed to be faster than that of single coherent states and we show that for a resonant bath the dissipation leads to an increase in the decoherence rate as compared to the low frequency bath.

Semiclassical dynamics of open quantum systems: Comparing the finite with the infinite perspective

“…where y is the N B -dimensional bath coordinate vector and s is the 1-dimensional coordinate vector of the system of interest and N B + 1 = N. This expression was used for the investigation of systems interacting with a bath at temperature T = 0 [29].…”

“…Here we address this issue by comparing results obtained with the explicit Semiclassical Hybrid Dynamics (SCHD) [28,29] and with the implicit Semiclassical Brownian Motion (SCBM) method [30,31]. Since both methods employ a semiclassical propagator, they have a similar range of applicability and are thus ideal for direct comparison.…”

Quantum energy and coherence exchange with discrete baths

“…We start by mentioning the methods which have focused on an explicit quantum dynamical treatment of the system + bath dynamics: path integral approaches [10][11][12], the multiconfiguration time-dependent Hartree (MCTDH) technique for wave packet propagation [13], the Gaussian-MCTDH approach [1], the effective-mode representation [14], and the local coherentstate approximation to system-bath dynamics [15]. Another way of studying the system + bath dynamics is to solve the non-Markovian master equations [16][17][18], including some semiclassical approaches [19,20].…”

“…The main result found is that finite baths may induce a non-Markovian dynamics on the system particle. From the quantum point of view, most works [1,9,15,20,36,39] focus on the analysis of changing the frequency distributions and the coupling strength between system and bath. In a distinct context analytical results [40] studied the time evolution of the concurrence and the purity of two interacting qubits embedded in finite and infinite numbers of environmental spins.…”

Dissipative dynamics with the corrected propagator method. Numerical comparison between fully quantum and mixed quantum/classical simulations

“…The semiclassical initial value representation (SC-IVR) [18,19] and the frozen Gaussian method [20], followed by the coherent state form of the semiclassical propagator [21][22][23][24], led to numerous applications to systems with many degrees of freedom [25][26][27][28][29][30][31][32][33][34][35][36]. In this context we should note the work of Pollak et al [37][38][39] in which the SC-IVR was used as a zeroth order term in the correction expansion of the exact quantum propagator.…”