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H. Boschi-Filho

Publications and source records attributed to H. Boschi-Filho.

18 recordsLinked to original sources
arXiv2013

Anomalous dimensions and scalar glueball spectroscopy in AdS/QCD

An extended version of the AdS/QCD Soft-Wall model that incorporates QCD-like anomalous contributions to the dimensions of gauge theory operators is proposed. This exploratory approach leads to a relation between scalar glueball masses and beta functions. Using this relation, properties of the glueball mass spectroscopy that emerge from phenomenological beta functions proposed in the literature are investigated. The reverse problem is also considered: starting from a linear Regge trajectory which fits the lattice glueball masses, beta functions with different asymptotic infrared behaviours are found. Remarkably, some of them present a fixed point at finite coupling.

hep-th↗
arXiv2011

Non-Relativistic Propagators via Schwinger's Method

In order to popularize the so called Schwinger's method we reconsider the Feynman propagator of two non-relativistic systems: a charged particle in a uniform magnetic field and a charged harmonic oscillator in a uniform magnetic field. Instead of solving the Heisenberg equations for the position and the canonical momentum operators, ${\bf R}$ and ${\bf P}$, we apply this method by solving the Heisenberg equations for the gauge invariant operators ${\bf R}$ and $\mathversion{bold}$π$ = {\bf P}-e{\bf A}$, the latter being the mechanical momentum operator. In our procedure we avoid fixing the gauge from the beginning and the result thus obtained shows explicitly the gauge dependence of the Feynman propagator.

quant-ph↗
arXiv2006

Scattering and Bound State Green's Functions on a Plane via so(2,1) Lie Algebra

We calculate the Green's functions for the particle-vortex system, for two anyons on a plane with and without a harmonic regulator and in a uniform magnetic field. These Green's functions which describe scattering or bound states (depending on the specific potential in each case) are obtained exactly using an algebraic method related to the SO(2,1) Lie group. From these Green's functions we obtain the corresponding wave functions and for the bound states we also find the energy spectra.

quant-ph↗
arXiv2004

BFFT formalism applied to the minimal chiral Schwinger model

We consider the minimal chiral Schwinger model, by embedding the gauge noninvariant formulation into a gauge theory following the Batalin-Fradkin-Fradkina-Tyutin point of view. Within the BFFT procedure, the second class constraints are converted into strongly involutive first-class ones, leading to an extended gauge invariant formulation. We also show that, like the standard chiral model, in the minimal chiral model the Wess-Zumino action can be obtained by performing a q-number gauge transformation into the effective gauge noninvariant action.

hep-th↗
arXiv2003

Three Methods for Computing the Feynman Propagator

We present three methods for calculating the Feynman propagator for the non-relativistic harmonic oscillator. The first method was employed by Schwinger a half a century ago, but has rarely been used in non-relativistic problems since. Also discussed is an algebraic method and a path integral method so that the reader can compare the advantages and disadvantages of each method.

quant-ph↗
arXiv2003

QCD/String holographic mapping and high energy scattering amplitudes

We find a one to one mapping between low energy string dilaton states in AdS bulk and high energy glueball states on the corresponding boundary. This holographic mapping leads to a relation between bulk and boundary scattering amplitudes. From this relation and the dilaton action we find the appropriate momentum scaling for high energy QCD amplitudes at fixed angles.

hep-th↗
arXiv2002

Virial coefficients from 2+1 dimensional QED effective actions at finite temperature and density

From spinor and scalar 2+1 dimensional QED effective actions at finite temperature and density in a constant magnetic field background, we calculate the corresponding virial coefficients for particles in the lowest Landau level. These coefficients depend on a parameter theta related to the time-component of the gauge field, which plays an essential role for large gauge invariance. The variation of the parameter theta might lead to an interpolation between fermionic and bosonic virial coefficients, although these coefficients are singular for theta=pi/2.

hep-th↗
arXiv2000

BFFT quantization and dynamical solutions of a fluid field theory

We study a field theory formulation of a fluid mechanical model. We implement the Hamiltonian formalism by using the BFFT conjecture in order to build a gauge invariant fluid field theory. We also generalize previous known classical dynamical field solutions for the fluid model.

hep-th↗
arXiv2000

Symmetry transform in the Faddeev-Jackiw quantization of dual models

We study the presence of symmetry transformations in the Faddeev-Jackiw approach for constrained systems. Our analysis is based in the case of a particle submitted to a particular potential which depends on an arbitrary function. The method is implemented in a natural way and symmetry generators are identified. These symmetries permit us to obtain the absent elements of the sympletic matrix which complement the set of Dirac brackets of such a theory. The study developed here is applied in two different dual models. First, we discuss the case of a two-dimensional oscillator interacting with an electromagnetic potential described by a Chern-Simons term and second the Schwarz-Sen gauge theory, in order to obtain the complete set of non-null Dirac brackets and the correspondent Maxwell electromagnetic theory limit.

hep-th↗
arXiv2000

The effect of a topological gauge field on Bose-Einstein condensation

We show that Bose-Einstein condensation of charged scalar fields interacting with a topological gauge field at finite temperature is inhibited except for special values of the topological field. We also show that fermions interacting with this topological gauge field can condense for some values of the gauge field.

hep-th↗
arXiv1999

Domain defects in systems of two real scalar fields

In this work we investigate the role of the symmetry of the Lagrangian on the existence of defects in systems of coupled scalar fields. We focus attention mainly on solutions where defects may nest defects. When space is non-compact we find topological BPS and non-BPS solutions that present internal structure. When space is compact the solutions are nontopological sphalerons, which may be nested inside the topological defects. We address the question of classical stability of these topological and nontopological solutions and investigate how the thermal corrections may modify the classical scenario.

hep-th↗
arXiv1998

Quasiperiodic fields and Bose-Einstein condensation

We construct a partition function for fields obeying a quasiperiodic boundary condition at finite temperature, $ψ(0;\vec x)= e^{iθ} ψ(β;\vec x)$, which interpolate continously that ones corresponding to bosons and fermions and discuss the possibility of condensation for these fields.

hep-th↗
arXiv1998

Generalized partition functions, interpolating statistics and higher virial coefficients

Starting from determinants at finite temperature obeying an intermediate boundary condition between the periodic (bosonic) and antiperiodic (fermionic) cases, we find results which can be mapped onto the ones obtained from anyons for the second virial coefficient. Using this approach, we calculate the corresponding higher virial coefficients and compare them with the results known in the literature.

hep-th↗
arXiv1998

Generalized partition functions and interpolating statistics

We show that the assumption of quasiperiodic boundary conditions (those that interpolate continuously periodic and antiperiodic conditions) in order to compute partition functions of relativistic particles in 2+1 space-time can be related with anyonic physics. In particular, in the low temperature limit, our result leads to the well known second virial coefficient for anyons. Besides, we also obtain the high temperature limit as well as the full temperature dependence of this coefficient.

hep-th↗
arXiv1997

Second virial coefficient for real gases at high temperature

We study the second virial coefficient, $B(T)$, for simple real gases at high temperature. Theoretical arguments imply that there exists a certain temperature, $T_i$, for each gas, for which this coefficient is a maximum. However, the experimental data clearly exhibits this maximum only for the Helium gas. We argue that this is so because few experimental data are known in the region where these maxima should appear for other gases. We make different assumptions to estimate $T_i$. First, we adopt an empirical formulae for $B(T)$. Secondly, we assume that the intermolecular potential is the Lennard-Jones one and later we interpolate the known experimental data of $B(T)$ for Ar, He, Kr, H_2, N_2, O_2, Ne and Xe with simple polynomials of arbitrary powers, combined or not with exponentials. With these assumptions we estimate the values of $T_i$ for these gases and compare them.

cond-mat↗
arXiv1995

GENERALIZED THERMAL ZETA-FUNCTIONS

We calculate the partition function of a harmonic oscillator with quasi-periodic boundary conditions using the zeta-function method. This work generalizes a previous one by Gibbons and contains the usual bosonic and fermionic oscillators as particular cases. We give an alternative prescription for the analytic extension of the generalized Epstein function involved in the calculation of the generalized thermal zeta-functions. We also conjecture about the relation of our calculation to anyonic systems.

hep-th↗
arXiv1994

The Partition Function for an Anyon-Like Oscillator

We compute the partition function of an anyon-like harmonic oscillator. The well known results for both the bosonic and fermionic oscillators are then reobtained as particular cases as ours. The technique we employ is a non-relativistic version of the Green function method used in the computation of one-loop effective actions of quantum field theory.

hep-th↗