Percolation transition in quantum Ising and rotor models with sub-Ohmic dissipation

Autor(es)

Al-Ali, Manal ^[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, BR-13560970 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Physical Review B; v. 86, n. 7 AUG 13 2012.
• Citações Web of Science: 2

Resumo

We investigate the influence of sub-Ohmic dissipation on randomly diluted quantum Ising and rotor models. The dissipation causes the quantum dynamics of sufficiently large percolation clusters to freeze completely. As a result, the zero-temperature quantum phase transition across the lattice percolation threshold separates an unusual super-paramagnetic cluster phase from an inhomogeneous ferromagnetic phase. We determine the low-temperature thermodynamic behavior in both phases, which is dominated by large frozen and slowly fluctuating percolation clusters. We relate our results to the smeared transition scenario for disordered quantum phase transitions, and we compare the cases of sub-Ohmic, Ohmic, and super-Ohmic dissipation. (AU)

• Processo FAPESP: 10/03749-4 - Transições de fase quânticas: efeitos de desordem e dissipação
• Beneficiário: José Abel Hoyos Neto
• Modalidade de apoio: Auxílio à Pesquisa - Regular