PMID- 37259990
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20230601
LR  - 20230601
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 158
IP  - 21
DP  - 2023 Jun 7
TI  - Tree tensor network state approach for solving hierarchical equations of motion.
LID - 211102 [pii]
LID - 10.1063/5.0153870 [doi]
AB  - The hierarchical equations of motion (HEOM) method is a numerically exact open 
      quantum system dynamics approach. The method is rooted in an exponential 
      expansion of the bath correlation function, which in essence strategically 
      reshapes a continuous environment into a set of effective bath modes that allow 
      for more efficient cutoff at finite temperatures. Based on this understanding, 
      one can map the HEOM method into a Schrodinger-like equation, with a 
      non-Hermitian super-Hamiltonian for an extended wave function being the tensor 
      product of the central system wave function and the Fock state of these effective 
      bath modes. In this work, we explore the possibility of representing the extended 
      wave function as a tree tensor network state (TTNS) and the super-Hamiltonian as 
      a tree tensor network operator of the same structure as the TTNS, as well as the 
      application of a time propagation algorithm using the time-dependent variational 
      principle. Our benchmark calculations based on the spin-boson model with a 
      slow-relaxing bath show that the proposed HEOM+TTNS approach yields consistent 
      results with those of the conventional HEOM method, while the computation is 
      considerably sped up. In addition, the simulation with a genuine TTNS is four 
      times faster than a one-dimensional matrix product state decomposition scheme.
CI  - (c) 2023 Author(s). Published under an exclusive license by AIP Publishing.
FAU - Ke, Yaling
AU  - Ke Y
AUID- ORCID: 0000-0001-6625-3981
AD  - Institute of Physics, University of Freiburg, Hermann-Herder-Strasse 3, 79104 
      Freiburg, Germany.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
SB  - IM
EDAT- 2023/06/01 13:09
MHDA- 2023/06/01 13:10
CRDT- 2023/06/01 06:53
PHST- 2023/04/12 00:00 [received]
PHST- 2023/05/16 00:00 [accepted]
PHST- 2023/06/01 13:10 [medline]
PHST- 2023/06/01 13:09 [pubmed]
PHST- 2023/06/01 06:53 [entrez]
AID - 2893702 [pii]
AID - 10.1063/5.0153870 [doi]
PST - ppublish
SO  - J Chem Phys. 2023 Jun 7;158(21):211102. doi: 10.1063/5.0153870.