2003/03/31 by Amit Dutta, Diptiman Sen · 3 citations
Mathematics · Physics and Astronomy · #Algebraic structures and combinatorial models #Physics of Superconductivity and Magnetism #Quantum many-body systems #cond-mat.stat-mech #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.67.094435
published as Phys. Rev. B 67 (2002) 094435 · Expanded version of cond-mat/0208216; Revtex, 7 pages, 2 eps figures
openalex publication_date 2003/03/31 · arxiv created 2003/04/18 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
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 nontrivial 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-flip transition; it separates two gapped phases in one of which the Z2 symmetry of the Hamiltonian is broken. Our study has a bearing on one of the transitions of the axial next-nearest neighbor Ising 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.