On the Quantization of the Abelian Chern-Simons Coefficient at Finite Temperature

We show that when the Abelian \CS\ theory coupled to matter fields is quantized in a vacuum with non vanishing magnetic flux (or electric charge), the requirement of gauge invariance at finite temperature leads to the quantization of the \CS\ coefficient and its quantum corrections, in a manner similar to the non-Abelian case.Comment: 11 pages, LaTeX, no figures, no special macros. Some discussion and references added. A minor error corrected. Final version to appear in Phys. Lett.

Thermodynamics of relativistic fermions with Chern-Simons coupling.

We study the thermodynamics of the relativistic quantum field theory of massive fermions in three space-time dimensions coupled to an Abelian Maxwell-Chern-Simons gauge field. We evaluate the specific heat at finite temperature and density and find that the variation with the statistical angle is consistent with the nonrelativistic ideas on generalized statistics.Facultad de Ciencias Exacta

On the center-vortex baryonic area law

We correct an unfortunate error in an earlier work of the author, and show that in center-vortex QCD (gauge group SU(3)) the baryonic area law is the so-called $Y$ law, described by a minimal area with three surfaces spanning the three quark world lines and meeting at a central Steiner line joining the two common meeting points of the world lines. (The earlier claim was that this area law was a so-called $\Delta$ law, involving three extremal areas spanning the three pairs of quark world lines.) We give a preliminary discussion of the extension of these results to $SU(N), N>3$. These results are based on the (correct) baryonic Stokes' theorem given in the earlier work claiming a $\Delta$ law. The $Y$-form area law for SU(3) is in agreement with the most recent lattice calculations.Comment: 5 pages, RevTeX4, 5 .eps figure

On The Finite Temperature Chern-Simons Coefficient

We compute the exact finite temperature effective action in a 0+1-dimensional field theory containing a topological Chern-Simons term, which has many features in common with 2+1-dimensional Chern-Simons theories. This exact result explains the origin and meaning of puzzling temperature dependent coefficients found in various naive perturbative computations in the higher dimensional models.Comment: 11 pages LaTeX; no figure

Induced Parity Breaking Term at Finite Temperature

We compute the exact induced parity-breaking part of the effective action for 2+1 massive fermions in $QED_3$ at finite temperature by calculating the fermion determinant in a particular background. The result confirms that gauge invariance of the effective action is respected even when large gauge transformations are considered.Comment: to be published in Physical Review Letters. 5 pages, Revtex, no figure

Gauge Invariance, Finite Temperature and Parity Anomaly in D=3

The effective gauge field actions generated by charged fermions in $QED_3$ and $QCD_3$ can be made invariant under both small and large gauge transformations at any temperature by suitable regularization of the Dirac operator determinant, at the price of parity anomalies. We resolve the paradox that the perturbative expansion is not invariant, as manifested by the temperature dependence of the induced Chern-Simons term, by showing that large (unlike small) transformations and hence their Ward identities, are not perturbative order-preserving. Our results are illustrated through concrete examples of field configurations.Comment: 4 pages, RevTe

Derivative expansion and large gauge invariance at finite temperature

We study the 0+1 dimensional Chern-Simons theory at finite temperature within the framework of derivative expansion. We obtain various interesting relations, solve the theory within this framework and argue that the derivative expansion is not a suitable formalism for a study of the question of large gauge invariance.Comment: 12 pages, Late

Abelian and Non-Abelian Induced Parity Breaking Terms at Finite Temperature

We compute the exact canonically induced parity breaking part of the effective action for 2+1 massive fermions in particular Abelian and non Abelian gauge field backgrounds. The method of computation resorts to the chiral anomaly of the dimensionally reduced theory.Comment: 13 pages, RevTeX, no figure

Thermodynamic properties of spontaneous magnetization in Chern-Simons QED_3

The spontaneous magnetization in Chern-Simons QED_3 is discussed in a finite temperature system. The thermodynamical potential is analyzed within the weak field approximation and in the fermion massless limit. We find that there is a linear term with respect to the magnetic field with a negative coefficient at any finite temperature. This implies that the spontaneous magnetic field does not vanish even at high temperature. In addition, we examine the photon spectrum in the system. We find that the bare Chern-Simons coefficient is cancelled by the radiative effects. The photons then become topologically massless according to the magnetization, though they are massive by finite temperature effects. Thus the magnetic field is a long-range force without the screening even at high temperature.Comment: 32 pages, Latex, 4 eps figure

Casimir scaling as a test of QCD vacuum

Recent accurate measurements of static potentials between sources in various representations of the gauge group SU(3) performed by G.Bali provide a crucial test of the QCD vacuum models and different approaches to confinement. The Casimir scaling of the potential observed for all measured distances implies strong suppression of higher cumulant contributions. The consequences for the instanton vacuum model and the spectrum of the QCD string are also discussed.Comment: LaTeX, 15 pages, 1 figur