E. F. Moreno

SCHEME INDEPENDENCE AND THE EXACT RENORMALIZATION GROUP

Abstract We compute critical exponents in a Z2 symmetric scalar field theory in three dimensions, using Wilsons exact renormalization group equations expanded in powers of derivatives. A nontrivial relation between these exponents is confirmed explicitly at the first two orders in the derivative expansion. At leading order all our results are cutoff independent, while at next-to-leading order they are not, and the determination of critical exponents becomes ambiguous. We discuss the possible ways in which this scheme ambiguity might be resolved.

Wess-Zumino-Witten and fermion models in noncommutative space

Abstract We analyze the connection between Wess–Zumino–Witten and free fermion models in two-dimensional noncommutative space. Starting from the computation of the determinant of the Dirac operator in a gauge field background, we derive the corresponding bosonization recipe studying, as an example, bosonization of the U(N) Thirring model. Concerning the properties of the noncommutative Wess–Zumino–Witten model, we construct an orbit-preserving transformation that maps the standard commutative WZW action into the noncommutative one.

The Wess-Zumino-Witten term in non-commutative two-dimensional fermion models

We study the effective action associated to the Dirac operator in two dimensional non-commutative Field Theory. Starting from the axial anomaly, we compute the determinant of the Dirac operator and we find that even in the U(1) theory, a Wess-Zumino-Witten like term arises.

Self-dual Chern-Simons solitons in noncommutative space

We construct exact soliton solutions to the Chern-Simons-Higgs system in non-commutative space, for non-relativistic and relativistic models. In both cases we find regular vortex-like solutions to the BPS equations which approach the ordinary selfdual non-topological and topological solitons when he non-commutative parameter θ goes to zero.

Non Abelian Bosonization in Two and Three Dimensions

Abstract We discuss non-abelian bosonization of two- and three-dimensional fermions using a pathintegral framework in which the bosonic action follows from the evaluation of the fermion determinant for the Dirac operator in the presence of a vector field. This naturally leads to the Wess-Zumino-Witten action for massless two-dimensional fermions and to a Chem-Simons action for very massive three-dimensional fermions. One advantage of our approach is that it allows one to derive the exact bosonization recipe for fermion currents in a systematic way.

Monopole solutions in AdS space

Abstract We find monopole solutions for a spontaneously broken SU (2)-Higgs system coupled to gravity in asymptotically anti-de Sitter space. We present new analytic and numerical results discussing, in particular, how the gravitational instability of self-gravitating monopoles depends on the value of the cosmological constant.We find monopole solutions for a spontaneously broken SU(2)-Higgs system coupled to gravity in asymptotically anti-de Sitter space. We present new analytic and numerical results discussing,in particular, how the gravitational instability of self-gravitating monopoles depends on the value of the cosmological constant.

On three dimensional bosonization

Abstract We discuss Abelian and non-Abelian three dimensional bosonization within the path-integral framework. We present a systematic approach leading to the construction of the bosonic action which, together with the bosonization recipe for fermion currents, describes the original fermion system in terms of vector bosons.

EXACT RENORMALIZATION GROUP STUDY OF FERMIONIC THEORIES

Abstract The exact renormalization group approach (ERG) is developed for the case of pure fermionic theories by deriving a Grassmann version of the ERG equation and applying it to the study of fixed point solutions and critical exponents of the two-dimensional chiral Gross-Neveu model. An approximation based on the derivative expansion and a further truncation in the number of fields is used. Two solutions are obtained analytically in the limit N → ∞, with N being the number of fermionic species. For finite N some fixed point solutions, with their anomalous dimensions and critical exponents, are computed numerically. The issue of separation of physical results from the numerous spurious ones is discussed. We argue that one of the solutions we find can be identified with that of Dashen and Frishman, whereas the others seem to be new ones.

Holographic phase transition from dyons in an AdS black hole background

We construct a dyon solution for a Yang-Mills-Higgs theory in a 4 dimensional Schwarzschild-anti-de Sitter black hole background with temperature T. We then apply the AdS/CFT correspondence to describe the strong coupling regime of a 2 + 1 quantum field theory which undergoes a phase transition exhibiting the condensation of a composite charge operator below a critical temperature Tc.

Monopoles in non-Abelian Dirac-Born-Infeld theory

We investigate monopole solutions for the Born-Infeld Higgs system. We analyze numerically these solutions and compare them with the standard {close_quote}t Hooft{endash}Polyakov monopoles. We also discuss the existence of a critical value of {beta} (the Born-Infeld {open_quotes}absolute field parameter{close_quotes}) below which no regular solution exists. {copyright} {ital 1999} {ital The American Physical Society}