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Vadim Zeitlin

Publications and source records attributed to Vadim Zeitlin.

8 recordsLinked to original sources
arXiv1998

Collective Excitations in Thermal QED_{3+1}: Survival of the Fittest

The spectrum of collective fermionic excitations in a finite temperature QED_{3+1} is studied in different regimes. It is shown that within the standard perturbation approach the one-loop dispersion equation, besides the ordinary one-particle excitation, has four new solutions. The additional excitations are gauge-dependent and two of them have nonphysical signs of residues in the propagator poles. The temperature evolution of the solutions is investigated and it is shown that the use of effective propagators leaves no more than one additional mode which becomes propagating at $T \bolpor 10M$, when the gauge invariance is restored. The other three modes, including those with nonphysical residues in the propagator poles, are always strongly damped, thus the thermal effects do not produce pathologies in QED_{3+1}.

hep-th↗
arXiv1998

Curing Fermion Mass Gauge Variance in QED$_{2+1}$

The problem of the gauge dependence of the fermion mass in the Maxwell-Chern-Simons QED$_{2+1}$ is revisited. Using Proca mass term as an intermediate infrared regulator we are demonstrating gauge-invariance of the fermion mass shell in QED$_{2+1}$ in all orders of the perturbation theory.

hep-th↗
arXiv1997

Induced Magnetic Field in a Finite Fermion Density Maxwell QED$_{2+1}$

We are studying finite fermion density states in Maxwell QED$_{2+1}$ with external magnetic field. It is shown that at any fermion density the energy of some magnetized states may be less than that of the state with the same density, but no magnetic field. Magnetized states are described by the effective Maxwell-Chern-Simons QED$_{2+1}$ Lagrangian with gauge field mass proportional to the number of filled Landau levels.

hep-th↗
arXiv1996

Spontaneous Magnetization in Maxwell QED$_{2+1}$

Spontaneous magnetization in the Maxwell QED$_{2+1}$ at finite fermion density is studied. It is shown that at low fermion densities the one-loop free energy has its minimum at some nonvanishing value of the magnetic field. The magnetization is due to the asymmetry of the fermion spectrum of the massive QED$_{2+1}$ in an external magnetic field.

hep-th↗
arXiv1995

Effective Lagrangian of Thermal QED with External Magnetic Field and the Static Limit of the Polarization Operator

A low-temperature expansion of QED one-loop effective Lagrangian valid for a wide range of parameters is presented in a form of finite sums of elementary functions. Starting from the effective action components of the one-loop polarization operator responsible for Hall conductivity and Debye screening are obtained. It is shown that in a strong background magnetic field the Debye radius depends on spatial direction.

hep-ph↗
arXiv1994

Low-Temperature QED with External Magnetic Field

Low-temperature expansion of the effective Lagrangian of the QED$_{3+1}$ with a uniform magnetic field and a finite chemical potential is performed. Temperature corrections, as well as zero-temperature expression for the effective Lagrangian are presented as finite sums over partially filled Landau levels.

hep-ph↗
arXiv1994

QED$_{2+1}$ with Nonzero Fermion Density and Quantum Hall Effect

A general expression for the conductivity in the QED$_{2+1}$ with nonzero fermion density in the uniform magnetic field is derived. It is shown that the conductivity is entirely determined by the Chern-Simons coefficient: $σ_{ij}=\varepsilon_{ij}~{\cal C}$ and is a step-function of the chemical potential and the magnetic field.

hep-th↗