Two-Time Correlation Function of a Two-Dimensional Quantal Rotator in a Colored Noise

概要

論文の詳細を見る
We study an absorption spectrum of a two-dimensional rotator coupled to a colored harmonic-oscillator bath. The absorption spectrum is analytically calculated from the generating functional of a reduced density matrix element for the rotator degrees of freedom. In the previous letter [J. Phys. Soc. Jpn. 70 (2001) 1167], the analysis of spectrum is limited to a white noise case. In this paper, we extend our theory to a colored noise case. We present the spectra for different temperatures, damping strength, and the correlation time of the noise. For a weakly damped rotator, at low temperatures, the spectra are sensitive to the system dynamics that is determined by the quantization of the rotational motion. Such a quantized rotational motion depends on the noise effects. Hence we observe the peak shifts by the noise correlation time. For a strongly damped rotator, we find the bimodal spectrum in the slow modulation case. One of the peaks is caused by the effect of the colored noise, which dose not appear in the case of the white noise. This peak is related to a librational motion induced by the coupling between the system and the bath oscillators with the near zero frequencies.
Physical Society of Japanの論文
2002-10-15