Real-Space Renormalization Group (RSRG) Approach to Quantum Spin Lattice Systems

TL;DR

This paper introduces a variational modification to the real-space renormalization group method, improving ground state energy estimates for quantum spin lattice models like ITF, XX, and Heisenberg systems.

Contribution

It presents a novel variational approach to RSRG, enhancing accuracy in energy bounds for quantum spin systems compared to traditional methods.

Findings

Achieves better upper bounds for ground state energies.

Successfully applied to exactly solvable models.

Demonstrates improved accuracy over standard RSRG.

Abstract

The paper describes an explicit variational modification of the standard RSRG method and its application to quantum spin lattice systems. The modified approach is applied to exactly solvable ITF, XX and isotropic Heisenberg models. Better upper bounds for the systems' ground state energy are obtained as compared to the standard RSRG approach.