Low-temperature density matrix renormalization group using regulated polynomial expansion

TL;DR

This paper introduces a finite-temperature DMRG method using regulated polynomial expansion, enabling accurate calculations of static and dynamical properties in one-dimensional quantum systems at low temperatures.

Contribution

It presents a novel finite-temperature DMRG approach employing regulated polynomial expansion and single-target states, improving low-temperature calculations.

Findings

Accurate results for the 1D Hubbard model at low temperatures.

Effective static and dynamical quantity computations.

Demonstrates the method's applicability to quantum many-body systems.

Abstract

We propose a density matrix renormalization group (DMRG) technique at finite temperatures. As is the case of the ground state DMRG, we use a single-target state that is calculated by making use of a regulated polynomial expansion. Both static and dynamical quantities are obtained after a random-sampling and averaging procedure. We apply this technique to the one-dimensional Hubbard model at half filling and find that this gives excellent results at low temperatures.