Collective Modes at a Disordered Quantum Phase Transition

Autor(es)

Puschmann, Martin ^[1] ; Crewse, Jack ^[1] ; Hoyos, Jose A. ^[2] ; Vojta, Thomas ^[1]

Afiliação do(s) autor(es)

^[1] Missouri Univ Sci & Technol, Dept Phys, Rolla, MO 65409 - USA

^[2] Univ Sao Paulo, Inst Fis Sao Carlos, CP 369, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Physical Review Letters; v. 125, n. 2 JUL 10 2020.
• Citações Web of Science: 0

Resumo

We study the collective excitations, i.e., the Goldstone (phase) mode and the Higgs (amplitude) mode, near the superfluid-Mott glass quantum phase transition in a two-dimensional system of disordered bosons. Using Monte Carlo simulations as well as an inhomogeneous quantum mean-field theory with Gaussian fluctuations, we show that the Higgs mode is strongly localized for all energies, leading to a noncritical scalar response. In contrast, the lowest-energy Goldstone mode undergoes a striking delocalization transition as the system enters the superfluid phase. We discuss the generality of these findings and experimental consequences, and we point out potential relations to many-body localization. (AU)

• Processo FAPESP: 16/10826-1 - EMU concedido no processo 2015/23849-7: cluster de computadores
• Beneficiário: Francisco Castilho Alcaraz
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários
• Processo FAPESP: 15/23849-7 - Cadeias quânticas de spins
• Beneficiário: Francisco Castilho Alcaraz
• Modalidade de apoio: Auxílio à Pesquisa - Temático