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Iván Schmidt

Publications and source records attributed to Iván Schmidt.

27 records · Page 2Linked to original sources
arXiv2013

Lepton masses and mixings in a $A_{4}$ multi-Higgs model with radiative seesaw mechanism

We propose a renormalizable multi-Higgs model with $A_{4}\otimes Z_{2}\otimes Z^{\prime}_{2}$ symmetry, accounting for the experimental deviation from the tribimaximal mixing pattern of the neutrino mixing matrix. In this framework we study the charged lepton and neutrino masses and mixings. The light neutrino masses are generated via a radiative seesaw mechanism, which involves a single heavy Majorana neutrino and neutral scalars running in the loops. The obtained neutrino mixings and mass squared splittings are in good agreement with the neutrino oscillation experimental data for both normal and inverted hierarchy. The model predicts an effective Majorana neutrino mass $m_{ββ}=$ 4 meV and 50 meV for the normal and the inverted neutrino spectrum, respectively. The model also features a suppression of CP violation in neutrino oscillations, a low scale for the heavy Majorana neutrino (few TeV) and, due to the unbroken $Z_2$ symmetry, a natural dark matter candidate.

hep-ph↗
arXiv2012

One- and two-dimensional reductions of the mean-field description of degenerate Fermi gases

We study collective behavior of Fermi gases trapped in various external potentials, including optical lattices (OLs), in the framework of the mean-field (hydrodynamic) description. Using the variational method, we derive effective dynamical equations for the one- and two-dimensional (1D and 2D) settings from the general 3D mean-field equation. The respective confinement is provided by trapping potentials with the cylindrical and planar symmetry, respectively. The resulting equations are nonpolynomial Schr% ödinger equations (NPSEs) coupled to equations for the local transverse size of the trapped states. Numerical simulations demonstrate close agreement of results produced by the underlying 3D equation and the effective low-dimensional ones. We consider the ground state in these settings. In particular, analytical solutions are obtained for the effectively 2D non-interacting Fermi gas. Differences between the 1D and 2D configurations are highlighted. Finally, we analyze the dependence of the 1D and 2D density patterns of the trapped gas, in the presence of the OL, on the strengths of the confining and OL potentials, and on the scattering length which determines the strength of interactions between non-identical fermions.

cond-mat.quant-gas↗
arXiv2010

Coulomb's law corrections from a gauge-kinetic mixing

We study the static quantum potential for a gauge theory which includes the mixing between the familiar photon $U(1)_{QED}$ and a second massive gauge field living in the so-called hidden-sector $U(1)_h$. Our discussion is carried out using the gauge-invariant but path-dependent variables formalism, which is alternative to the Wilson loop approach. Our results show that the static potential is a Yukawa correction to the usual static Coulomb potential. Interestingly, when this calculation is done inside a superconducting box, the Coulombic piece disappears leading to a screening phase.

hep-th↗
arXiv2007

Properties of noncommutative axionic electrodynamics

Using the gauge-invariant but path-dependent variables formalism, we compute the static quantum potential for noncommutative axionic electrodynamics, and find a radically different result than the corresponding commutative case. We explicitly show that the static potential profile is analogous to that encountered in both non-Abelian axionic electrodynamics and in Yang-Mills theory with spontaneous symmetry breaking of scale symmetry.

hep-th↗
arXiv2006

Remarks on Axion-like models

For a recently proposed alternative to the traditional axion model, we study its long distance behavior, in particular the confinement versus screening issue, and show that a compactified version of this theory can be further mapped into the massive Schwinger model. Our calculation is based on the gauge-invariant but path-dependent variables formalism. This result agrees qualitatively with the usual axion model.

hep-th↗
arXiv2003

Coulomb's law modification in nonlinear and in noncommutative electrodynamics

We study the lowest-order modifications of the static potential for Born-Infeld electrodynamics and for the $θ$-expanded version of the noncommutative U(1) gauge theory, within the framework of the gauge-invariant but path-dependent variables formalism. The calculation shows a long-range correction ($1/r^5$-type) to the Coulomb potential in Born-Infeld electrodynamics. However, the Coulomb nature of the potential (to order $e^2$) is preserved in noncommutative electrodynamics.

hep-th↗
arXiv2001

Remarks on Screening in a Gauge-Invariant Formalism

In this paper we display a direct and physically attractive derivation of the screening contribution to the interaction potential in the Chiral Schwinger model and generalized Maxwell-Chern-Simons gauge theory. It is shown that these results emerge naturally when a correct separation between gauge-invariant and gauge degrees of freedom is made. Explicit expressions for gauge-invariant fields are found.

hep-th↗
arXiv1999

From Screening to Confinement in a Gauge-Invariant Formalism

Features of screening and confinement are reviewed in two-dimensional quantum electrodynamics (QED2). Our discussion is carried out using the gauge-invariant but path-dependent variables formalism. This alternative and useful approach exploits the rich structure of the electromagnetic cloud or dressing around static fermions in a straightforward and simple way.

hep-th↗