Spectral properties of a spin-incoherent Luttinger Liquid

TL;DR

This paper uses DMRG to study the spectral properties of strongly interacting one-dimensional fermionic systems at finite temperature, focusing on the crossover to spin-incoherent Luttinger liquid behavior when temperature is comparable to the spin energy.

Contribution

The paper introduces a DMRG-based method to analyze the spectral properties of the $t-J$ model across the full temperature range, including the challenging crossover regime.

Findings

Identification of spectral signatures of spin-incoherent behavior

Access to the regime where temperature is comparable to the spin energy

Insights into the crossover from Luttinger liquid to spin-incoherent regime

Abstract

We present time-dependent density matrix renormalization group (DMRG) results for strongly interacting one dimensional fermionic systems at finite temperature. When interactions are strong the characteristic spin energy can be greatly suppressed relative to the characteristic charge energy, allowing for the possibility of spin-incoherent Luttinger liquid physics when the temperature is high compared to the spin energy, but small compared to the charge energy. Using DMRG we compute the spectral properties of the $t-J$ model at arbitrary temperatures with respect to both spin and charge energies. We study the full crossover from the Luttinger liquid regime to the spin-incoherent regime,focusing on small $J/t$, where the signatures of spin-incoherent behavior are more manifest. Our method allows us to access the analytically intractable regime where temperature is of the order of the spin energy, $T\sim J$. Our results should be helpful in the interpretation of experiments that may be in the crossover regime, $T\sim J$, and apply to one-dimensional cold atomic gases where finite-temperature effects are appreciable. The technique may also be used to guide the development of analytical approximations for the crossover regime.