Gapless line for the anisotropic Heisenbergspin−12chain in a magnetic field and the quantum axial next-nearest-neighbor Ising chain

Dutta, Amit ; Sen, Diptiman (2003) Gapless line for the anisotropic Heisenbergspin−12chain in a magnetic field and the quantum axial next-nearest-neighbor Ising chain Physical Review B, 67 (9). ISSN 0163-1829

Full text not available from this repository.

Official URL: http://doi.org/10.1103/PhysRevB.67.094435

Related URL: http://dx.doi.org/10.1103/PhysRevB.67.094435

Abstract

We study the anisotropic Heisenberg (XYZ) spin-1/2 chain placed in a magnetic field pointing along the x-axis. We use bosonization and a renormalization group analysis to show that the model has a non-trivial fixed point at a certain value of the XY anisotropy a and the magnetic field h. Hence, there is a line of critical points in the (a,h) plane on which the system is gapless, even though the Hamiltonian has no continuous symmetry. The quantum critical line corresponds to a spin-flop transition; it separates two gapped phases in one of which the Z_2 symmetry of the Hamiltonian is broken. Our study has a bearing on one of the transitions of the axial next-nearest neighbor Ising (ANNNI) chain in a transverse magnetic field. We also discuss the properties of the model when the magnetic field is increased further, in particular, the disorder line on which the ground state is a direct product of single spin states.

Item Type:Article
Source:Copyright of this article belongs to American Physical Society.
ID Code:117218
Deposited On:21 Apr 2021 12:11
Last Modified:21 Apr 2021 12:11

Repository Staff Only: item control page