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arXiv · 2509.24525

Reducing Spatial and Temporal Dimensionality in the Multidimensional Caldeira-Leggett Model

Hongfei Zhan·Ernest W. Z. Pan·Zhenning Cai
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Abstract

Focusing on the real-time dynamics of the reduced density matrix of the multidimensional Caldeira-Leggett model, several techniques are adopted in this paper to reduce the spatial and temporal dimensionality, combined into an efficient algorithm. From a spatial perspective, an equivalent formulation of the Dyson series is presented. With the aid of a low-rank approximation, the spatial dimensionality of open quantum system simulations is halved. From a temporal perspective, the frozen Gaussian approximation is used to approximate both the evolution operator and the interaction operator in the multidimensional Caldeira-Leggett model. This reduces the high-dimensional integrals to one- and two-dimensional integrals independent of the truncation level of the Dyson series. Through these techniques, we design an efficient algorithm whose validity is verified through several numerical experiments, including a two-dimensional double slit simulation.

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Hongfei Zhan, Ernest W. Z. Pan, Zhenning Cai. 2025-09-29. Reducing Spatial and Temporal Dimensionality in the Multidimensional Caldeira-Leggett Model. https://doi.org/10.22331/q-2026-09-02-2201

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