Tuning the disorder of superglasses

TL;DR

This paper investigates how quantum fluctuations influence the coexistence of superfluidity and glassy or magnetic orders in disordered bosonic systems, revealing the stabilization of superglass phases and shifts in phase transition points.

Contribution

It demonstrates through quantum Monte Carlo simulations that quantum fluctuations stabilize superglass phases and alter transition points in disordered bosonic models.

Findings

Quantum fluctuations stabilize superglass phases.

Transition points shift due to quantum effects.

Antiferromagnetic order coexists with superfluidity in a supersolid.

Abstract

We study the interplay of superfluidity, glassy and magnetic orders of hardcore bosons with random frustrating interactions. In the classical limit, this model reduces to a $\pm J$ Edwards-Anderson Ising model with concentration $p$ of the ferromagnetic bonds, which hosts a glassy-ferromagnetic transition at a critical concentration $p_c^{\rm cl}\sim 0.77$ on a 3D cubic lattice. Our quantum Monte Carlo simulation results using the worm algorithm show that quantum fluctuations stabilize the coexistence of superfluidity and glassy order ("superglass"), and shift the (super)glassy-ferromagnetic transition to $p_c> p_c^{\rm cl}$. In contrast, antiferromagnetic order coexists with superfluidity to form a supersolid, and the transition to the glassy phase occurs at a higher $p$.