Precise evaluation of thermal response functions by optimized density matrix renormalization group schemes

Understand

This paper provides a study and discussion of earlier as well as novel more efficient schemes for the precise evaluation of finite-temperature response functions of strongly correlated quantum systems in the framework of the time-dependent density matrix renormalization group (tDMRG).

• The computational costs and bond dimensions as functions of time and temperature are examined for the example of the spin-1/2 XXZ Heisenberg chain in the critical XY phase and the gapped N\'eel phase.
• The matrix product state purifications occurring in the algorithms are in one-to-one relation with corresponding matrix product operators.
• This notational simplification elucidates implications of quasi-locality on the computational costs.