Autor(es)

Quito, V. L. ; Hoyos, Jose A. ; Miranda, E.

• Tipo de documento: Artigo Científico
• Fonte: PHYSICAL REVIEW B; v. 94, n. 6, p. 27-pg., 2016-08-03.

Resumo

We study the low-energy physics of a broad class of time-reversal invariant and SU(2)-symmetric one-dimensional spin-S systems in the presence of quenched disorder via a strong-disorder renormalization-group technique. We show that, in general, there is an antiferromagnetic phase with an emergent SU(2S + 1) symmetry. The ground state of this phase is a random singlet state in which the singlets are formed by pairs of spins. For integer spins, there is an additional antiferromagnetic phase which does not exhibit any emergent symmetry (except for S = 1). The corresponding ground state is a random singlet one but the singlets are formed mostly by trios of spins. In each case the corresponding low-energy dynamics is activated, i.e., with a formally infinite dynamical exponent, and related to distinct infinite-randomness fixed points. The phase diagram has two other phases with ferromagnetic tendencies: a disordered ferromagnetic phase and a large spin phase in which the effective disorder is asymptotically finite. In the latter case, the dynamical scaling is governed by a conventional power law with a finite dynamical exponent. (AU)

• Processo FAPESP: 15/23849-7 - Cadeias quânticas de spins
• Beneficiário: Francisco Castilho Alcaraz
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 07/57630-5 - Métodos não perturbativos aplicados a sistemas eletrônicos correlacionados
• Beneficiário: Eduardo Miranda
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 09/17531-3 - Estudos de sistemas quânticos fortemente desordenados
• Beneficiário: Victor Luiz Quito
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto