Chiral Y junction of quantum spin chains

Buccheri, F. (Institut für Theoretische Physik, Heinrich-Heine-Universität, Düsseldorf, D-40225, Germany) ; Egger, R. (Institut für Theoretische Physik, Heinrich-Heine-Universität, Düsseldorf, D-40225, Germany) ; G. Pereira, R. (Institut für Theoretische Physik, Heinrich-Heine-Universität, Düsseldorf, D-40225, Germany) (International Institute of Physics, Universidade Federal do Rio Grande do Norte, Campus Universitario, Lagoa Nova, Natal, RN, 59078-970, Brazil) (Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal, RN, 59078-970, Brazil) ; B. Ramos, F. (International Institute of Physics, Universidade Federal do Rio Grande do Norte, Campus Universitario, Lagoa Nova, Natal, RN, 59078-970, Brazil)

12 March 2019

Abstract: We study a Y junction of spin-1/2 Heisenberg chains with an interaction that breaks both time-reversal and chain exchange symmetries, but not their product nor SU(2) symmetry. The boundary phase diagram features a stable disconnected fixed point at weak coupling and a stable three-channel Kondo fixed point at strong coupling, separated by an unstable chiral fixed point at intermediate coupling. Using non-abelian bosonization and boundary conformal field theory, together with density matrix renormalization group and quantum Monte Carlo simulations, we characterize the signatures of these low-energy fixed points. In particular, we address the boundary entropy, the spin conductance, and the temperature dependence of the scalar spin chirality and the magnetic susceptibility at the boundary.


Published in: Nuclear Physics B 941 (2019) 794-837 DOI: 10.1016/j.nuclphysb.2019.03.005
License: CC-BY-3.0



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