Symmetries of the hubbard model and the theta term in the sigma-model

Journal Article · Thu Dec 01 04:00:00 EST 1988 · Mod. Phys. Letters B; (United States)

DOI:https://doi.org/10.1142/S0217732388002087· OSTI ID:6436084

Balachandran, A P; Bowick, M J; Gupta, K S; Srivastava, A M ^[1]

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1. Physics Dept., Syracuse Univ., Syracuse, NY (US)

Recently, it has been shown that the strong coupling limit of the half-filled Hubbard model has SU(2) gauge invariance. The 2 + 1-dimensional nonlinear sigma model with the customary theta term does not have this symmetry--instead it has a U(1) gauge symmetry. A modification of the theta term is suggested so that the model acquires SU(2)--or rather SO(3)--gauge symmetry. The symmetries of this modified model thus resemble more closely those of the strongly coupled half-filled Hubbard model. Gauge invariance of the new model, unlike that of the U(1) model, requires quantization of the angle theta. The allowed theta values are m..pi../2 (mod 2..pi..) with m an integer. Hence the allowed soliton spins are m/4 (melement ofZ) while their statistics are governed by their spins in the usual way.

• OSTI ID: 6436084
• Journal Information: Mod. Phys. Letters B; (United States), Journal Name: Mod. Phys. Letters B; (United States) Vol. 3:17; ISSN MPLBE
• Country of Publication: United States
• Language: English

Related Subjects

645300* -- High Energy Physics-- Particle Invariance Principles & Symmetries
645400 -- High Energy Physics-- Field Theory
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANGULAR MOMENTUM
GAUGE INVARIANCE
INVARIANCE PRINCIPLES
LIE GROUPS
MATHEMATICAL MODELS
NONLINEAR PROBLEMS
ONE-DIMENSIONAL CALCULATIONS
PARTICLE MODELS
PARTICLE PROPERTIES
QUANTIZATION
QUASI PARTICLES
SIGMA MODEL
SOLITONS
SPIN
SU GROUPS
SU-2 GROUPS
SYMMETRY GROUPS
TWO-DIMENSIONAL CALCULATIONS
U GROUPS
U-1 GROUPS