On condensation of charged scalars in D=3 dimensions

By using the gauge-invariant, but path-dependent, variables formalism, we study the impact of condensates on physical observables for a three-dimensional Higgs-like model. As a result, for the case of a physical mass term like $m_H^2 \phi ^ * \phi$, we recover a screening potential. Interestingly enough, in the case of a "wrong-sign" mass term $- m_H^2 \phi ^ * \phi$, unexpected features are found. It is shown that the interaction energy is the sum of an effective-Bessel and a linear potential, leading to the confinement of static charges. However, when a Chern-Simons term is included, the surprising result is that the theory describes an exactly screening phase.Comment: 13 page

Confinement from spontaneous breaking of scale symmetry

We show that one can obtain naturally the confinement of static charges from the spontaneous symmetry breaking of scale invariance in a gauge theory. At the classical level a confining force is obtained and at the quantum level, using a gauge invariant but path-dependent variables formalism, the Cornell confining potential is explicitly obtained. Our procedure answers completely to the requirements by 't Hooft for ''perturbative confinement''.Comment: 6 page

Static potential from spontaneous breaking of scale symmetry

We determine the static potential for a heavy quark-antiquark pair from the spontaneous symmetry breaking of scale invariance in a non-Abelian gauge theory. Our calculation is done within the framework of the gauge-invariant, path-dependent, variables formalism. The result satisfies the 't Hooft basic criterion for achieving confinement.Comment: 13 pages, Latex, no figures; final version accepted for publication in PLB, new references and comments, physical results unchange

Aspects of finite electrodynamics in D=3 dimensions

We study the impact of a minimal length on physical observables for a three-dimensional axionic electrodynamics. Our calculation is done within the framework of the gauge-invariant, but path-dependent, variables formalism which is alternative to the Wilson loop approach. Our result shows that the interaction energy contains a regularised Bessel function and a linear confining potential. This calculation involves no theta expansion at all. Once again, the present analysis displays the key role played by the new quantum of length.Comment: 12 pages, 2 figures; reference list updated and extended; new aknowlegments; removed line after eq.(1) erroneously inserte

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.Comment: 13 pages, 1 figure, to appear in PR

Confinement effects from interacting chromo-magnetic and axion fields

We study a non-Abelian gauge theory with a pseudo scalar coupling \phi \epsilon ^{\mu \nu \alpha \beta} F_{\mu \nu}^a F_{\alpha \beta}^a in the case where a constant chromo-electric, or chromo-magnetic, strength expectation value is present. We compute the interaction potential within the framework of gauge-invariant, path-dependent, variables formalism. While in the case of a constant chromo-electric field strength expectation value the static potential remains Coulombic, in the case of a constant chromo-magnetic field strength the potential energy is the sum of a Coulombic and a linear potentials, leading to the confinement of static charges.Comment: 12 pages, no figures, published versio

Stress Inversion in a Gelatin Box: Testing Eruptive Vent Location Forecasts With Analog Models

Assessing volcanic hazard in regions of distributed volcanism is challenging because of the uncertain location of future vents. A statistical-mechanical strategy to forecast such locations was recently proposed: here, we further develop and test it with analog models. We stress a gelatin block laterally and with surface excavations, and observe air-filled crack trajectories. We use the observed surface arrivals to sample the distributions of parameters describing the stress state of the gelatin block, combining deterministic crack trajectory simulations with a Monte Carlo approach. While the individual stress parameters remain unconstrained, we effectively retrieve their ratio and successfully forecast the arrival points of subsequent cracks

Dynamical Couplings, Dynamical Vacuum Energy and Confinement/Deconfinement from R^2-Gravity

We study within Palatini formalism an f(R)-gravity with f(R)= R + \alpha R^2 interacting with a dilaton and a special kind of nonlinear gauge field system containing a square-root of the standard Maxwell term, which is known to produce confinement in flat space-time. Reformulating the model in the physical Einstein frame we find scalar field effective potential with a flat region where the confinement dynamics disappears, while in other regions it remains intact. The effective gauge couplings as well as the induced cosmological constant become dynamical. In particular, a conventional Maxwell kinetic term for the gauge field is dynamically generated even if absent in the original theory. We find few interesting classes of explicit solutions: (i) asymptotically (anti-)de Sitter black holes of non-standard type with additional confining vacuum electric potential even for the electrically neutral ones; (ii) non-standard Reissner-Nordstroem black holes with additional constant vacuum electric field and having non-flat-spacetime "hedgehog" asymptotics; (iii) generalized Levi-Civitta-Bertotti-Robinson "tube-like" space-times.Comment: 16 page

On scale symmetry breaking and confinement in D=3 models

Within the framework of the gauge-invariant, but path-dependent, variables formalism, we study the connection between scale symmetry breaking and confinement in three-dimensional gluodynamics. We explicitly show that the static potential profile contains a linear potential, leading to the confinement of static charges. Also, we establish a new type of equivalence among different three-dimensional effective theories.Comment: 6 pages, references adde