Quantum Simulation of Lindbladian Dynamics via Repeated Interactions

Fuente: arXiv
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Main Authors: Pocrnic, Matthew, Segal, Dvira, Wiebe, Nathan
Format: Preprint
Published: 2023
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author Pocrnic, Matthew
Segal, Dvira
Wiebe, Nathan
author_facet Pocrnic, Matthew
Segal, Dvira
Wiebe, Nathan
contents The Lindblad equation generalizes the Schrödinger equation to quantum systems that undergo dissipative dynamics. The quantum simulation of Lindbladian dynamics is therefore non-unitary, preventing a naive application of state-of-the-art quantum algorithms. Here, we make use of an approximate correspondence between Lindbladian dynamics and evolution based on Repeated Interaction (RI) CPTP maps to write down a Hamiltonian formulation of the Lindblad dynamics and derive a rigorous error bound on the master equation. Specifically, we show that the number of interactions needed to simulate the Liouvillian $e^{t\mathcal{L}}$ within error $ε$ scales in a weak coupling limit as $ν\in O(t^2\|\mathcal{L}\|_{1\rightarrow 1}^2/ε)$. This is significant because the error in the Lindbladian approximation to the dynamics is not explicitly bounded in existing quantum algorithms for open system simulations. We then provide quantum algorithms to simulate RI maps using an iterative Qubitization approach and Trotter-Suzuki formulas and specifically show that for iterative Qubitization the number of operations needed to simulate the dynamics (for a fixed value of $ν$) scales in a weak coupling limit as $O(α_0 t + ν\log(1/ε)/\log\log(1/ε))$ where $α_0$ is the coefficient $1$-norm for the system and bath Hamiltonians. This scaling would appear to be optimal if the complexity of $ν$ is not considered, which underscores the importance of considering the error in the Liouvillian that we reveal in this work.
format Preprint
id arxiv_https___arxiv_org_abs_2312_05371
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Quantum Simulation of Lindbladian Dynamics via Repeated Interactions
Pocrnic, Matthew
Segal, Dvira
Wiebe, Nathan
Quantum Physics
The Lindblad equation generalizes the Schrödinger equation to quantum systems that undergo dissipative dynamics. The quantum simulation of Lindbladian dynamics is therefore non-unitary, preventing a naive application of state-of-the-art quantum algorithms. Here, we make use of an approximate correspondence between Lindbladian dynamics and evolution based on Repeated Interaction (RI) CPTP maps to write down a Hamiltonian formulation of the Lindblad dynamics and derive a rigorous error bound on the master equation. Specifically, we show that the number of interactions needed to simulate the Liouvillian $e^{t\mathcal{L}}$ within error $ε$ scales in a weak coupling limit as $ν\in O(t^2\|\mathcal{L}\|_{1\rightarrow 1}^2/ε)$. This is significant because the error in the Lindbladian approximation to the dynamics is not explicitly bounded in existing quantum algorithms for open system simulations. We then provide quantum algorithms to simulate RI maps using an iterative Qubitization approach and Trotter-Suzuki formulas and specifically show that for iterative Qubitization the number of operations needed to simulate the dynamics (for a fixed value of $ν$) scales in a weak coupling limit as $O(α_0 t + ν\log(1/ε)/\log\log(1/ε))$ where $α_0$ is the coefficient $1$-norm for the system and bath Hamiltonians. This scaling would appear to be optimal if the complexity of $ν$ is not considered, which underscores the importance of considering the error in the Liouvillian that we reveal in this work.
title Quantum Simulation of Lindbladian Dynamics via Repeated Interactions
topic Quantum Physics
url https://arxiv.org/abs/2312.05371