Mean-Field Interacting Boson Random Point Fields in Weak Harmonic Traps

A model of the mean-field interacting boson gas trapped by a weak harmonic potential is considered by the \textit{boson random point fields} methods. We prove that in the Weak Harmonic Trap (WHT) limit there are two phases distinguished by the boson condensation and by a different behaviour of the local particle density. For chemical potentials less than a certain critical value, the resulting Random Point Field (RPF) coincides with the usual boson RPF, which corresponds to a non-interacting (ideal) boson gas. For the chemical potentials greater than the critical value, the boson RPF describes a divergent (local) density, which is due to \textit{localization} of the macroscopic number of condensed particles. Notice that it is this kind of transition that observed in experiments producing the Bose-Einstein Condensation in traps

Transversal adaptive filtering

This paper presents a tutorial on the gradient (G) and recursive least squares (RLS) algorithme, both commonly used in adaptive transversal filters for estimating a linear model . It is shown how the algorithms utilize recursivity ta realize at the saine time the averaging involved in the optimisation criterion as well as the minimization. In steady state both algorithms can be viewed as minimizing the saure mean square error criterion. Then they have equivalent performances : the saure residual fluctuations up to an equivalence between the adaptation step-size t of (G) and the forgetting rate (1-w) of (RLS) . Due to the criterion itself emphasizing adaptation speed, it is the transient period which exhibits the (RLS) superiority . This is essentially at the price of a four times higher complexity and of difficulties with controling numerical effects, related (in part) to the presence of divisions that are not in (G) . A general methodology for decoupling the transient effects and permanent fluctuations is given ; the latter are due to the measurement noise disturbing the model . The more general problem of tracking the model variations is treated with that methodology and we emphasize the différence between the problems of tracking and of squeezing the transient period for a fixed model : the corresponding adaptation step-sizes differ significantly .Synthèse sur les algorithmes du gradient et des moindres carrés rapides. En régime permanent, ils ont des performances équivalentes. C'est en régime transitoire que les moindres carrés sont supérieurs; ceci au prix d'une complexité environ quatre fois supérieure et de difficultés de contrôle des variables numérique

Dynamics of charge-displacement channeling in intense laser-plasma interactions

The dynamics of transient electric fields generated by the interaction of high intensity laser pulses with underdense plasmas has been studied experimentally with the proton projection imaging technique. The formation of a charged channel, the propagation of its front edge and the late electric field evolution have been characterised with high temporal and spatial resolution. Particle-in-cell simulations and an electrostatic, ponderomotive model reproduce the experimental features and trace them back to the ponderomotive expulsion of electrons and the subsequent ion acceleration.Comment: 5 figures, accepted for publication in New Journal of Physic

Eynard-Mehta theorem, Schur process, and their pfaffian analogs

We give simple linear algebraic proofs of Eynard-Mehta theorem, Okounkov-Reshetikhin formula for the correlation kernel of the Schur process, and Pfaffian analogs of these results. We also discuss certain general properties of the spaces of all determinantal and Pfaffian processes on a given finite set.Comment: AMSTeX, 21 pages, a new section adde

Adaptive filtering techniques for gravitational wave interferometric data: Removing long-term sinusoidal disturbances and oscillatory transients

It is known by the experience gained from the gravitational wave detector proto-types that the interferometric output signal will be corrupted by a significant amount of non-Gaussian noise, large part of it being essentially composed of long-term sinusoids with slowly varying envelope (such as violin resonances in the suspensions, or main power harmonics) and short-term ringdown noise (which may emanate from servo control systems, electronics in a non-linear state, etc.). Since non-Gaussian noise components make the detection and estimation of the gravitational wave signature more difficult, a denoising algorithm based on adaptive filtering techniques (LMS methods) is proposed to separate and extract them from the stationary and Gaussian background noise. The strength of the method is that it does not require any precise model on the observed data: the signals are distinguished on the basis of their autocorrelation time. We believe that the robustness and simplicity of this method make it useful for data preparation and for the understanding of the first interferometric data. We present the detailed structure of the algorithm and its application to both simulated data and real data from the LIGO 40meter proto-type.Comment: 16 pages, 9 figures, submitted to Phys. Rev.

Evidence of resonant surface wave excitation in the relativistic regime through measurements of proton acceleration from grating targets

The interaction of laser pulses with thin grating targets, having a periodic groove at the irradiated surface, has been experimentally investigated. Ultrahigh contrast ($\sim 10^{12}$) pulses allowed to demonstrate an enhanced laser-target coupling for the first time in the relativistic regime of ultra-high intensity >10^{19} \mbox{W/cm}^{2}. A maximum increase by a factor of 2.5 of the cut-off energy of protons produced by Target Normal Sheath Acceleration has been observed with respect to plane targets, around the incidence angle expected for resonant excitation of surface waves. A significant enhancement is also observed for small angles of incidence, out of resonance.Comment: 5 pages, 5 figures, 2nd version implements final correction

Conditional Intensity and Gibbsianness of Determinantal Point Processes

The Papangelou intensities of determinantal (or fermion) point processes are investigated. These exhibit a monotonicity property expressing the repulsive nature of the interaction, and satisfy a bound implying stochastic domination by a Poisson point process. We also show that determinantal point processes satisfy the so-called condition $(\Sigma_{\lambda})$ which is a general form of Gibbsianness. Under a continuity assumption, the Gibbsian conditional probabilities can be identified explicitly.Comment: revised and extende

Consensus Statement on Animals’ Relationship with Pediatric Oncohematological Patients, on Behalf of Infectious Diseases and Nurse Working Groups of the Italian Association of Pediatric Hematology-Oncology

: Contact with animals in pediatric oncohematologic patients is associated with many benefits, but the risk of contracting zoonoses, even if low, must be considered by clinicians. In order to assess the awareness about this topic, we surveyed the Italian pediatric oncohematology centers, which resulted in heterogeneous responses. The Infectious Diseases Working Group and the Nurse Working Group of the Italian Association of Pediatric Hematology-Oncology, together with veterinarians from the National Federation of Italian Veterinarians, drew up a consensus document to unify the indications to be given to families with the aim of guaranteeing a safe interaction between patients and animals and improving the collaboration of clinicians with veterinarians and families