Testing baryon number conservation in braneworld models with cold neutrons

In the context of multi-brane Universe models, matter swapping between two braneworlds is allowed leading to a baryon number violation in our visible world. An experimental framework is described to test such a phenomenology with cold neutrons thanks to a neutron-shining-through-a-wall experiment.Comment: 4 pages, 1 figure. Proceedings of the ESS Science Symposium on Neutron Particle Physics at Long Pulse Spallation Sources, NPPatLPS 2013 (25-27 March, 2013

Laser frequency combs and ultracold neutrons to probe braneworlds through induced matter swapping between branes

This paper investigates a new experimental framework to test the braneworld hypothesis. Recent theoretical results have shown the possibility of matter exchange between branes under the influence of suitable magnetic vector potentials. It is shown that the required conditions might be achieved with present-day technology. The experiment uses a source of pulsed and coherent electromagnetic radiation and relies on the Hansch frequency comb technique well-known in ultrahigh-precision spectroscopy. A good matter candidate for testing the hypothesis is a polarized ultracold neutron gas for which the number of swapped neutrons is measured.Comment: 14 pages, 4 figures. Published version. Published in Phys. Rev.

Plausible "faster-than-light" displacements in a two-sheeted spacetime

In this paper, we explore the implications of a two-point discretization of an extra-dimension in a five-dimensional quantum setup. We adopt a pragmatic attitude by considering the dynamics of spin-half particles through the simplest possible extension of the existing Dirac and Pauli equations. It is shown that the benefit of this approach is to predict new physical phenomena while maintaining the number of constitutive hypothesis at minimum. As the most striking feature of the model, we demonstrate the possibility of fermionic matter oscillations between the two four-dimensional sections and hyper-fast displacements in case of asymmetric warping (without conflicting special relativity). This result, similar to previous reported ones in brane-world theories, is completely original as it is derived by using quantum mechanics only without recourse to general relativity and bulk geodesics calculation. The model allows causal contact between normally disconnected regions. If it proves to be physically founded, its practical aspects could have deep implications for the search of extra-dimensions.Comment: 17 pages, 1 figure. Final version. Accepted for publication in Phys. Rev.

Quantum dynamics of particles in a discrete two-branes world model: Can matter particles exchange occur between branes?

In a recent paper, a model for describing the quantum dynamics of massive particles in a non-commutative two-sheeted spacetime was proposed. This model considers a universe made with two spacetime sheets embedded in a 5D bulk where the fifth dimension is restricted to only two points. It was shown that this construction has several important consequences for the quantum dynamics of massive particles. Most notably, it was demonstrated that a coupling arises between the two sheets allowing matter exchange in presence of intense magnetic vector potentials. In this paper, we show that non-commutative geometry is not absolutely necessary to obtain such a result since a more traditional approach allows one to reach a similar conclusion. The fact that two different approaches provide similar results suggests that standard matter exchange between branes might finally occur contrary to conventional belief.Comment: 11 pages, no figures. Final version. Published in Acta Physica Polonica

Artificially induced positronium oscillations in a two-sheeted spacetime: consequences on the observed decay processes

Following recent theoretical results, it is suggested that positronium (Ps) might undergo spontaneous oscillations between two 4D spacetime sheets whenever subjected to constant irrotational magnetic vector potentials. We show that these oscillations that would come together with o-Ps/p-Ps oscillations should have important consequences on Ps decay rates. Experimental setup and conditions are also suggested for demonstrating in non accelerator experiments this new invisible decay mode.Comment: 9 pages, 2 figures. Minor form correction. Accepted for publication in Int. J. of Modern Physics

Matter localization and resonant deconfinement in a two-sheeted spacetime

In recent papers, a model of a two-sheeted spacetime M4XZ2 was introduced and the quantum dynamics of massive fermions was studied in this framework. In the present study, we show that the physical predictions of the model are perfectly consistent with observations and most important, it can solve the puzzling problem of the four-dimensional localization of the fermion species in multidimensional spacetimes. It is demonstrated that fermion localization on the sheets arises from the combination of the discrete bulk structure and environmental interactions. The mechanism described in this paper can be seen as an alternative to the domain wall localization arising in continuous five dimensional spacetimes. Although tightly constrained, motions between the sheets are, however, not completely prohibited. As an illustration, a resonant mechanism through which fermion oscillations between the sheets might occur is described.Comment: 9 pages, 1 figure. Published version. Accepted for publication in Int. J. of Modern Physics

Non-reciprocal optical reflection from a bidimensional array of subwavelength holes in a metallic film

Using simulations and theoretical arguments we investigate the specular reflection of a perforated gold film deposited on a glass substrate. A square lattice of cylindrical holes is assumed to produce the periodic lateral corrugation needed to hybridize the surface plasmons with radiative states. It is shown that, contrasting transmission approaches, a knowledge of the reflection on either side of the film provides separate information on the gold-vacuum surface plasmons and on the gold-glass interface plasmons. Recent experimental data on a specific implementation of this system are reexamined; these show a good agreement between the measured reflections and the simulations in both directions of incident wave probes. This confirms the importance of taking into account the reflection asymmetry in the far-field assessment of surface plasmons properties.Comment: 4 pages, 3 figures. Published versio

Bounded modes to the rescue of optical transmission

This paper presents a brief survey of the evolution of knowledge about diffraction gratings. After recalling some basic facts, historically and physically, we introduce the concept of Wood anomalies. Next, we present some recent works in order to introduce the role of bounded modes in transmission gratings. The consequences of these recent results are then introduced. This paper is a secondary publication, published in Europhysics News (EPN 38, 3 (2007) 27-31). In the present version, some additional notes have been added with related references.Comment: 6 pages, 6 figures. Secondary publication. Brief revie

Role of Wood anomalies in optical properties of thin metallic films with a bidimensional array of subwavelength holes

Recents works deal with the optical transmission on arrays of subwavelength holes in a metallic layer deposited on a dielectric substrate. Making the system as realistic as possible, we perform simulations to enlighten the experimental data. This paper proposes an investigation of the optical properties related to the transmission of such devices. Numerical simulations give theoretical results in good agreement with experiment and we observe that the transmission and reflection behaviour correspond to Fano's profile correlated with resonant response of the eigen modes coupled with nonhomogeneous diffraction orders. We thus conclude that the transmission properties observed could conceivably be explained as resulting from resonant Wood's anomalies.Comment: 7 pages, 10 figures, 2 table

Quantum vacuum photon-modes and superhydrophobicity

Nanostructures are commonly used for developing superhydrophobic surfaces. However, available wetting theoretical models ignore the effect of vacuum photon-modes alteration on van der Waals forces and thus on hydrophobicity. Using first-principle calculations, we show that superhydrophibicity of nanostructured surfaces is dramatically enhanced by vacuum photon-modes tuning. As a case study, wetting contact angles of a water droplet above a polyethylene nanostructured surface are obtained from the interaction potential energy calculated as function of the droplet-surface separation distance. This new approach could pave the way for the design of novel superhydrophobic coatings.Comment: 5 pages, 4 figures, final version published in Physical Review Letter