Exact solution of a spin-1/2 $XX$ chain with three-site interactions in a random transverse field: Influence of randomness on quantum phase transition

Abstract

We present exact results for the ground-state and thermodynamic properties of the spin-1/2 $XX$ chain with three-site interactions in a random (Lorentzian) transverse field. We discuss the influence of randomness on the quantum critical behavior known to be present in the nonrandom model. We find that at zero temperature the characteristic features of the quantum phase transition, such as kinks in the magnetization versus field curve, are smeared out by randomness. However, at low but finite temperatures signatures of the quantum critical behavior are preserved if the randomness is not too large. Even the quantum critical region may be slightly enlarged for very weak randomness. In addition to the exact results for Lorentzian randomness we present a more general discussion of an arbitrarily random transverse magnetic field based on the inspection of the moments of the density of states.

11 pages, 8 figures

References in corpus (4)

• Exact eigenstates and macroscopic magnetization jumps in strongly frustrated spin lattices
• Dynamic properties of the spin-1/2 XY chain with three-site interactions
• Dynamic properties of quantum spin chains: Simple route to complex behavior
• Quantum dynamics of an Ising spin-chain in a random transverse field