93 research outputs found
Random magnetic field and quasi-particle transports in the mixed state of high T_{c} cuprates
By a singular gauge transformation, the quasi-particle transport in the mixed
state of high T_{c} cuprates is mapped into charge-neutral composite Dirac
fermion moving in short-range correlated random scalar and long-range
correlated vector potential. A fully quantum mechanical approach to
longitudinal and transverse thermal conductivities is presented. The
semi-classical Volovik effect is presented in a quantum mechanical way. The
quasi-particle scattering from the random magnetic field which was completely
missed in all the previous semi-classical approaches is the dominant scattering
mechanism at sufficiant high magnetic field. The implications for experiments
are discussed.Comment: 4+ pages, 1 figure. To appear in Phys. Rev. Let
On gauge-invariant Green function in 2+1 dimensional QED
Both the gauge-invariant fermion Green function and gauge-dependent
conventional Green function in dimensional QED are studied in the large
limit. In temporal gauge, the infra-red divergence of gauge-dependent
Green function is found to be regulariable, the anomalous dimension is found to
be . This anomalous dimension was argued to be
the same as that of gauge-invariant Green function. However, in Coulomb gauge,
the infra-red divergence of the gauge-dependent Green function is found to be
un-regulariable, anomalous dimension is even not defined, but the infra-red
divergence is shown to be cancelled in any gauge-invariant physical quantities.
The gauge-invariant Green function is also studied directly in Lorentz
covariant gauge and the anomalous dimension is found to be the same as that
calculated in temporal gauge.Comment: 8 pages, 6 figures, to appear in Phys. Rev.
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