Critical Behavior and Collective Modes at the Superfluid Transition in Amorphous Systems

Fuente: arXiv
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Autores principales: Kuttanikkad, Vishnu Pulloor, Puschmann, Martin, Narayanan, Rajesh, Vojta, Thomas
Formato: Preprint
Publicado: 2024
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author Kuttanikkad, Vishnu Pulloor
Puschmann, Martin
Narayanan, Rajesh
Vojta, Thomas
author_facet Kuttanikkad, Vishnu Pulloor
Puschmann, Martin
Narayanan, Rajesh
Vojta, Thomas
contents We investigate the critical behavior and the dynamics of the amplitude (Higgs) mode close to the superfluid-insulator quantum phase transition in an amorphous system (i.e., a system subject to topological randomness). In particular, we map the two-dimensional Bose-Hubbard Hamiltonian defined on a random Voronoi-Delaunay lattice onto a (2+1)-dimensional layered classical XY model with correlated topological disorder. We study the resulting model by laying recourse to classical Monte Carlo simulations. We specifically focus on the scalar susceptibility of the order parameter to study the dynamics of the amplitude mode. To do so, we harness the maximum entropy method to perform the analytic continuation of the scalar susceptibility to real frequencies. Our analysis shows that the amplitude mode remains delocalized in the presence of such topological disorder, quite at odds with its behavior in generic disordered systems, where the randomness localizes the Higgs mode. Furthermore, we show that the critical behavior of the topologically disordered system is identical to that of its translationally invariant counterpart, consistent with a modified Harris criterion. This suggests that the localization of the collective excitations in the presence of disorder is tied to the critical behavior of the quantum phase transition rather than a simple Anderson-localization-type interference mechanism.
format Preprint
id arxiv_https___arxiv_org_abs_2402_13757
institution arXiv
publishDate 2024
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spellingShingle Critical Behavior and Collective Modes at the Superfluid Transition in Amorphous Systems
Kuttanikkad, Vishnu Pulloor
Puschmann, Martin
Narayanan, Rajesh
Vojta, Thomas
Disordered Systems and Neural Networks
We investigate the critical behavior and the dynamics of the amplitude (Higgs) mode close to the superfluid-insulator quantum phase transition in an amorphous system (i.e., a system subject to topological randomness). In particular, we map the two-dimensional Bose-Hubbard Hamiltonian defined on a random Voronoi-Delaunay lattice onto a (2+1)-dimensional layered classical XY model with correlated topological disorder. We study the resulting model by laying recourse to classical Monte Carlo simulations. We specifically focus on the scalar susceptibility of the order parameter to study the dynamics of the amplitude mode. To do so, we harness the maximum entropy method to perform the analytic continuation of the scalar susceptibility to real frequencies. Our analysis shows that the amplitude mode remains delocalized in the presence of such topological disorder, quite at odds with its behavior in generic disordered systems, where the randomness localizes the Higgs mode. Furthermore, we show that the critical behavior of the topologically disordered system is identical to that of its translationally invariant counterpart, consistent with a modified Harris criterion. This suggests that the localization of the collective excitations in the presence of disorder is tied to the critical behavior of the quantum phase transition rather than a simple Anderson-localization-type interference mechanism.
title Critical Behavior and Collective Modes at the Superfluid Transition in Amorphous Systems
topic Disordered Systems and Neural Networks
url https://arxiv.org/abs/2402.13757