Exact treatment of the quantum Langevin equation under time-dependent system-bath coupling via a train of delta distributions

• URL: http://arxiv.org/abs/2505.00386v1
• Date: Thu, 01 May 2025 08:22:46 GMT
• Title: Exact treatment of the quantum Langevin equation under time-dependent system-bath coupling via a train of delta distributions
• Authors: Yuta Uenaga, Kensuke Gallock-Yoshimura, Takano Taira,
• Abstract summary: We consider the quantum Langevin equation for the Caldeira-Leggett model with an arbitrary time-dependent coupling constant.<n>We solve this equation exactly by employing a train of Dirac-delta switchings.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: In this paper, we consider the quantum Langevin equation for the Caldeira-Leggett model with an arbitrary time-dependent coupling constant. We solve this equation exactly by employing a train of Dirac-delta switchings. This method also enables us to visualize the memory effect in the environment. Furthermore, we compute the two-time correlation functions of the system's quadratures and show that the discrete-time Fourier transform is well-suited for defining spectral densities, as the Dirac-delta switchings turn continuous functions into discretized samples.

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