Open Quantum System Dynamics from Infinite Tensor Network Contraction

Research output: Contribution to journalResearch articleContributedpeer-review


Approaching the long-time dynamics of non-Markovian open quantum systems presents a challenging task if the bath is strongly coupled. Recent proposals address this problem through a representation of the so-called process tensor in terms of a tensor network. We show that for Gaussian environments highly efficient contraction to a matrix product operator (MPO) form can be achieved with infinite MPO evolution methods, leading to significant computational speed-up over existing proposals. The result structurally resembles open system evolution with carefully designed auxiliary degrees of freedom, as in hierarchical or pseudomode methods. Here, however, these degrees of freedom are generated automatically by the MPO evolution algorithm. Moreover, the semigroup form of the resulting propagator enables us to explore steady-state physics, such as phase transitions.


Original languageEnglish
Article number200403
Number of pages7
JournalPhysical review letters
Publication statusPublished - 17 May 2024

External IDs

ORCID /0000-0002-7806-3525/work/161406753
ORCID /0000-0002-1520-7931/work/161409214


ASJC Scopus subject areas


  • Dynamics of non-Markovian open quantum systems, process tensor, tensor network, matrix product operator, steady-state, phase transitions