2025/09/16 by Christensen, Hans Michael, Johannes Agerskov, Agerskov, Johannes +2
Computer Science · #Convolution (computer science) #Coupling (piping) #FOS: Physical sciences #Gaussian #Open quantum system #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Physics (quant-ph) #Quantum algorithm #Quantum computer #Quantum error correction #Quantum information #Qubit #Statistical Mechanics (cond-mat.stat-mech)
paper · pdf · doi:10.48550/arxiv.2509.12717
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2025/09/16 · openalex created_date 2025/10/18 · openalex updated_date 2026/08/05
We present a quantum algorithm for simulating open quantum systems coupled to Gaussian environments valid for any configuration and coupling strength. The algorithm is applicable to problems with strongly coupled, or non-Markovian, environments, problems with multiple environments out of mutual equilibrium, and problems with time-dependent Hamiltonians. We show that the algorithm can reproduce the true dynamics of such problems at arbitrary accuracy and, for a broad range of problems, only adds a minor resource cost relative to Trotterized time evolution; the cost is low-degree polynomial in the inverse target accuracy. The algorithm is based on the insight that any Gaussian environment can be represented as a train of ancillary qubits that sequentially interact with the system through a time-local coupling, given by the convolution square root of the bath correlation function; this is a secondary result of our work. Our results open up new applications of quantum computers for efficient simulation of non-equilibrium and open quantum systems.