scholarly journals Vertex correction and Ward identity in U(1) gauge theory with a Fermi surface

2010 ◽  
Vol 82 (7) ◽  
Author(s):  
Ki-Seok Kim
Keyword(s):  
Gauge Theory ◽  
Fermi Surface ◽  
Ward Identity ◽  
Vertex Correction

PROBING TOPOLOGICAL FEATURES IN PERTURBATIVE CHERN-SIMONS GAUGE THEORY

1990 ◽  
Vol 05 (23) ◽  
pp. 1833-1839 ◽  
Author(s):  
WEI CHEN ◽  
G. W. SEMENOFF ◽  
YONG-SHI WU
Keyword(s):  
Perturbation Theory ◽  
Gauge Theory ◽  
Ward Identity ◽  
Beta Function ◽  
Dimensional Regularization ◽  
Coupling Constant ◽  
Topological Features ◽  
Chern Simons

The topological Chern-Simons gauge theory is studied in the framework of perturbation theory. Both dimensional and F2 regularizations are used. We demonstrate the vanishing of the beta function up to three loops, the absence of diffeomorphism anomaly in the calculation of two- and three-point functions, and the validity of a topological Ward identity by finite renormalization of the coupling constant. The regularization dependence of the finite renormalization and an ambiguity in the dimensional regularization are also discussed.

scholarly journals U(1)×SU(2) Gauge Theory of Underdoped Cuprate Superconductors

1998 ◽  
Vol 12 (05) ◽  
pp. 173-180 ◽  
Author(s):  
P. A. Marchetti ◽  
Zhao-Bin Su ◽  
Lu Yu
Keyword(s):  
Gauge Theory ◽  
Fermi Surface ◽  
Transport Properties ◽  
Gauge Field ◽  
Spectral Function ◽  
Normal State ◽  
Doping Concentration ◽  
Cuprate Superconductors ◽  
Low Energy ◽  
Chern Simons

The U(1)×SU(2) Chern–Simons gauge theory is applied to study the 2D t–J model describing the normal state of underdoped cuprate superconductors. The U(1) field produces a flux phase for holons converting them into Dirac-like fermions, while the SU(2) field, due to the coupling to holons gives rise to a gap for spinons. An effective low-energy action involving holons, spinons and a self-generated U(1) gauge field is derived. The Fermi surface and electron spectral function obtained are consistent with photoemission experiments. The theory predicts a minimal gap proportional to doping concentration. It also explains anomalous transport properties.

THE FOCK–SCHWINGER GAUGE IN THE BFV FORMALISM

1991 ◽  
Vol 06 (17) ◽  
pp. 1597-1604 ◽  
Author(s):  
J. BARCELOS-NETO ◽  
CARLOS A. P. GALVÃO ◽  
P. GAETE
Keyword(s):  
Gauge Theory ◽  
Ward Identity ◽  
Free Field ◽  
Gauge Condition ◽  
General Ward ◽  
Abelian Gauge ◽  
Abelian Gauge Theory

We consider the implementation of a properly modified form of the Fock–Schwinger gauge condition in a general non-Abelian gauge theory in the context of the BFV formalism. Arguments are presented to justify the necessity of modifying the original Fock–Schwinger condition. The free field propagator and the general Ward identity are also calculated.

Supersymmetry Ward identity for the supersymmetric non-Abelian gauge theory

1980 ◽  
Vol 21 (8) ◽  
pp. 2203-2212 ◽  
Author(s):  
Parthasarathi Majumdar ◽  
Enrico C. Poggio ◽  
Howard J. Schnitzer
Keyword(s):  
Gauge Theory ◽  
Ward Identity ◽  
Abelian Gauge ◽  
Abelian Gauge Theory

scholarly journals Gauge-Theory Approach to Planar Doped Antiferromagnets and External Magnetic Fields

1998 ◽  
Vol 12 (07n08) ◽  
pp. 809-836 ◽  
Author(s):  
K. Farakos ◽  
N. E. Mavromatos
Keyword(s):  
Gauge Theory ◽  
Magnetic Fields ◽  
Fermi Surface ◽  
Dirac Fermion ◽  
Theory Approach ◽  
Dirac Fermions ◽  
Abelian Gauge ◽  
Planar Systems ◽  
Experimental Findings ◽  
D Wave

Within the framework of a relativistic non-Abelian gauge theory approach to the physics of spin–charge separation in doped quantum antiferromagnetic planar systems, proposed recently by the authors, we are examining here the effects of constant external magnetic fields on excitations about the superconducting state in the model. The electrically-charged Dirac fermions (holons), describing excitations about specific points on the fermi surface, e.g. those corresponding to the nodes of a d-wave superconducting gap in high-T c cuprates, condense, resulting in the opening of a Kosterlitz–Thouless–like gap (KT) at such nodes. This leads, in general, to a second superconducting phase transition, which occurs at low temperatures[Formula: see text], in addition to the high-T c superconductivity [Formula: see text] due to the bulk of the fermi surface for holons in a (d-wave) spin–charge separated superconductor. In the presence of strong external magnetic fields at the surface regions of the planar superconductor, in the direction perpendicular to the superconducting planes, these KT gaps appear to be enhanced. Our preliminary analysis, based on analytic Schwinger–Dyson treatments, seems to indicate that for an even number of Dirac fermion species, required in our model as a result of gauging a particle–hole SU(2) symmetry, Parity or Time Reversal violation does not necessarily occurs. Based on these considerations, we argue that recent experimental findings, concerning thermal conductivity plateaux of quasiparticles in planar high-T c cuprates in strong external magnetic fields, may indicate the presence of such KT gaps, caused by charged Dirac-fermion excitations in these materials, as suggested in the above model.

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