Temperature driven crossover phenomena in the correlation lengths of the one-dimensional t-J model

TL;DR

This paper introduces a modified TMRG algorithm to analyze the temperature-dependent crossover phenomena in the correlation lengths of the one-dimensional t-J model, connecting numerical results with CFT and confirming a spin-gap phase.

Contribution

A novel modified TMRG method is developed and applied to study the thermodynamics and correlation length crossover in the 1D t-J model, including comparison with Bethe ansatz and CFT.

Findings

Confirmed the existence of a spin-gap phase.

Analyzed the crossover from high T to quantum critical regime.

Connected numerical results with conformal field theory predictions.

Abstract

We describe a modified transfer matrix renormalization group (TMRG) algorithm and apply it to calculate thermodynamic properties of the one-dimensional t-J model. At the supersymmetric point we compare with Bethe ansatz results and make direct connection to conformal field theory (CFT). In particular we study the crossover from the non-universal high T lattice into the quantum critical regime by calculating various correlation lengths and static correlation functions. Finally, the existence of a spin-gap phase is confirmed.