Freiburg 2019 – wissenschaftliches Programm

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FM: Fall Meeting

FM 37: Open and Complex Quantum Systems II

FM 37.2: Talk

Dienstag, 24. September 2019, 14:15–14:30, 3042

Dissipation-assisted matrix product factorization — •Alejandro D. Somoza, Oliver Marty, James Lim, Susana F. Huelga, and Martin B. Plenio — Institut für Theoretische Physik and IQST, Universität Ulm, Ulm, Germany

Charge and energy transfer in biological and synthetic organic materials are strongly influenced by the coupling of electronic states to a highly structured dissipative environment. Non-perturbative simulations of these systems require a substantial computational effort and current methods can only be applied to large systems if environmental structures are severely coarse-grained. Time evolution methods based on tensor networks are fundamentally limited by the times that can be reached due to the buildup of entanglement in time, which quickly increases the size of the tensor representation, i.e., the bond dimension. In this work, we introduce a dissipation-assisted matrix product factorization (DAMPF) method that combines a tensor network representation of the vibronic state within a pseudomode description of the environment where a continuous bosonic environment is mapped into a few harmonic oscillators under Lindblad damping. This framework is particularly suitable for a tensor network representation, since damping suppresses the entanglement growth among oscillators and significantly reduces the bond dimension required to achieve a desired accuracy. We show that dissipation removes the *time-wall* limitation of existing methods, enabling the long-time simulation of large vibronic systems consisting of 10-50 sites coupled to 100-1000 underdamped modes in total and for a wide range of parameter regimes.