Martin, Jerome Vennin, Vincent

The Continuous Spontaneous Localisation (CSL) model solves the measurement problem of standard quantum mechanics, by coupling the mass density of a quantum system to a white-noise field. Since the mass density is not uniquely defined in general relativity, this model is ambiguous when applied to cosmology. We however show that most natural choices ...

Döge, Stefan Hingerl, Jürgen

The improvement of the number of extractable ultracold neutrons (UCNs) from converters based on solid deuterium (sD$_2$) crystals requires a good understanding of UCN transport and how the crystal's morphology influences its transparency to UCNs. Measurements of the UCN transmission through cryogenic liquids and solids of interest, such as hydrogen...

Garbet, Xavier Panico, O Varennes, R Gillot, C Dif-Pradalier, G Sarazin, Y Grandgirard, V Ghendrih, P Vermare, L

A model of E×B staircases is proposed, based on a wave kinetic equation coupled to a poloidal momentum equation. A staircase pattern is idealised as a periodic radial structure of zonal shear layers that bound regions of propagating wave packets, viewed as avalanches. Wave packets are trapped in shear flow layers due to refraction. In this model an...

Lahoche, Vincent Ouerfeli, Mohamed Samary, Dine Ousmane Tamaazousti, Mohamed

The tensorial principal component analysis is a generalization of ordinary principal component analysis focusing on data which are suitably described by tensors rather than matrices. This paper aims at giving the nonperturbative renormalization group formalism based on a slight generalization of the covariance matrix, to investigate signal detectio...

Friedrich, J. Gallon, S. Pumir, A. Grauer, R.

We propose and test a method to interpolate sparsely sampled signals by a stochastic process with a broad range of spatial and/or temporal scales. To this end, we extend the notion of a fractional Brownian bridge, defined as fractional Brownian motion with a given scaling (Hurst) exponent $H$ and with prescribed start and end points, to a bridge pr...

Martin, Jérôme Vennin, Vincent

Attempts to apply quantum collapse theories to Cosmology and cosmic inflation are reviewed. These attempts are motivated by the fact that the theory of cosmological perturbations of quantum-mechanical origin suffers from the single outcome problem, which is a modern incarnation of the quantum measurement problem, and that collapse models can provid...

Abel, C. Ayres, N. J. Ban, G. Bison, G. Bodek, K. Bondar, V. Chanel, E. Chiu, P. -J. Crawford, C. Daum, M.
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It has been proposed that there could be a mirror copy of the standard model particles, restoring the parity symmetry in the weak interaction on the global level. Oscillations between a neutral standard model particle, such as the neutron, and its mirror counterpart could potentially answer various standing issues in physics today. Astrophysical st...

Rambausek, M. Danas, Kostas

This work investigates the primary sinusoidal bifurcation wrinkling response of single-and multi-layered magne-torheological elastomer (MRE) film-substrate systems subjected to combined transverse applied magnetic fields and in-plane biaxial pre-compression. A recently proposed continuum model that includes the volume fraction of soft-magnetic part...

Zaïm, N. Guénot, D. Chopineau, L. Denoeud, A. Lundh, O. Vincenti, H. Quéré, F. Faure, J.

We present experimental results of vacuum laser acceleration (VLA) of electrons using radially polarized laser pulses interacting with a plasma mirror. Tightly focused radially polarized laser pulses have been proposed for electron acceleration because of their strong longitudinal electric field, making them ideal for VLA. However, experimental res...

Grain, Julien Vennin, Vincent

Canonical transformations are ubiquitous in Hamiltonian mechanics, since they not only describe the fundamental invariance of the theory under phase-space reparameterisations, but also generate the dynamics of the system. In the first part of this work we study the symplectic structure associated with linear canonical transformations. After reviewi...