Reusable selected-time channels for quantum simulation of non-Markovian dynamics

Abstract:Non-Markovian quantum-state diffusion (QSD) provides a microscopic trajectory description of open-system dynamics, but trajectories associated with a chosen initial state are not directly reusable as quantum channels. We develop a constructive framework that converts the QSD propagator into an input-independent Kraus channel for a fixed bath preparation and a selected evolution time. The construction incorporates reservoir memory through a finite-mode approximation of the bath covariance and yields a deterministic channel representation that can be compressed for approximate implementation with a system-ancilla circuit. For the qubit systems considered here, the construction closes exactly in vacuum and extends systematically to finite temperatures. Two-qubit examples with structured reservoirs validate the vacuum channel construction, illustrate its finite-temperature extension for a chosen initial state, and show that the complexity of the reservoir description can differ substantially from the ancilla space required for quantum realization. The framework therefore establishes a direct bridge from microscopic reservoir memory to reusable non-Markovian quantum simulation and provides a foundation for optimized hardware implementations and extensions to larger systems and multitime dynamics.

arXiv:2609.13456 [quant-ph]

(or arXiv:2609.13456v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2609.13456 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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