Convergence to equilibrium for many particle systems

The goal of this paper is to give a short review of recent results of the authors concerning classical Hamiltonian many particle systems. We hope that these results support the new possible formulation of Boltzmann's ergodicity hypothesis which sounds as follows. For almost all potentials, the minimal contact with external world, through only one particle of $N$, is sufficient for ergodicity. But only if this contact has no memory. Also new results for quantum case are presented

Local Ferroelectricity in SrTiO_3 Thin Films

The temperature-dependent polarization of SrTiO_3 thin films is investigated using confocal scanning optical microscopy. A homogeneous out-of-plane and inhomogeneous in-plane ferroelectric phase are identified from images of the linear electrooptic response. Both hysteretic and non-hysteretic behavior are observed under a dc bias field. Unlike classical transitions in bulk ferroelectrics, local ferroelectricity is observed at temperatures far above the dielectric permittivity maximum. The results demonstrate the utility of local probe experiments in understanding inhomogeneous ferroelectrics.Comment: 8 pages, 3 figures, accepted for publication in PR

Mobile telephone-delivered contingency management interventions promoting behaviour change in individuals with substance use disorders: a meta-analysis

BACKGROUND/AIMS: Contingency management (CM) interventions have gained considerable interest due to their success in the treatment of addiction. However, their implementation can be resource-intensive for clinical staff. Mobile telephone-based systems might offer a low-cost alternative. This approach could facilitate remote monitoring of behaviour and delivery of the reinforcer and minimize issues of staffing and resources. This systematic review and meta-analysis assessed the evidence for the effectiveness of mobile telephone-delivered CM interventions to promote abstinence (from drugs, alcohol and tobacco), medication adherence and treatment engagement among individuals with substance use disorders. DESIGN: A systematic search of databases (PsychINFO, CINAHL, MEDLINE PubMed, CENTRAL, Embase) for randomized controlled trials and within-subject design studies (1995-2019). The review was conducted in accordance with the PRISMA statement. The protocol was registered on PROSPERO. SETTING: All included studies originated in the United states. PARTICIPANTS: Seven studies were found, including 222 participants; two targeted alcohol abstinence among frequent drinkers and four targeted smoking cessation (in homeless veterans and those with post-traumatic stress disorder). One targeted medication adherence. MEASURES: The efficacy of CM to increase alcohol and nicotine abstinence was compared with control using several outcomes; percentage of negative samples (PNS), quit rate (QR) and longest duration abstinent (LDA) at the end of the intervention. FINDINGS: The random-effects meta-analyses produced pooled effect sizes of; PNS [d = 0.94, 95% confidence interval (CI) = 0.63-1.25], LDA (d = 1.08, 95% CI = 0.69-1.46) and QR (d = 0.46, 95% CI = 0.27-0.66), demonstrating better outcomes across the CM conditions. Most of the studies were rated as of moderate quality. 'Fail-safe N' computations for PNS indicated that 50 studies would be needed to produce a non-significant overall effect size. None could be calculated for QR and LDA due to insufficient number of studies. CONCLUSION: Mobile telephone-delivered contingency management performs significantly better than control conditions in reducing tobacco and alcohol use among adults not in treatment for substance use disorders

Quasi Two-dimensional Transfer of Elastic Waves

A theory for multiple scattering of elastic waves is presented in a random medium bounded by two ideal free surfaces, whose horizontal size is infinite and whose transverse size is smaller than the mean free path of the waves. This geometry is relevant for seismic wave propagation in the Earth crust. We derive a time-dependent, quasi-2D radiative transfer equation, that describes the coupling of the eigenmodes of the layer (surface Rayleigh waves, SH waves, and Lamb waves). Expressions are found that relate the small-scale fluctuations to the life time of the modes and to their coupling rates. We discuss a diffusion approximation that simplifies the mathematics of this model significantly, and which should apply at large lapse times. Finally, coherent backscattering is studied within the quasi-2D radiative transfer equation for different source and detection configurations.Comment: REVTeX, 36 pages with 10 figures. Submitted to Phys. Rev.

Electric circuit networks equivalent to chaotic quantum billiards

We formulate two types of electric RLC resonance network equivalent to quantum billiards. In the network of inductors grounded by capacitors squared resonant frequencies are eigenvalues of the quantum billiard. In the network of capacitors grounded by inductors squared resonant frequencies are given by inverse eigen values of the billiard. In both cases local voltages play role of the wave function of the quantum billiard. However as different from quantum billiards there is a heat power because of resistance of the inductors. In the equivalent chaotic billiards we derive the distribution of the heat power which well describes numerical statistics.Comment: 9 pages, 7 figure

On the Adaptive Real-Time Detection of Fast-Propagating Network Worms

We present two light-weight worm detection algorithms thatoffer significant advantages over fixed-threshold methods.The first algorithm, RBS (rate-based sequential hypothesis testing)aims at the large class of worms that attempts to quickly propagate, thusexhibiting abnormal levels of the rate at which hosts initiateconnections to new destinations. The foundation of RBS derives fromthe theory of sequential hypothesis testing, the use of which fordetecting randomly scanning hosts was first introduced by our previouswork with the TRW (Threshold Random Walk) scan detection algorithm. The sequential hypothesistesting methodology enables engineering the detectors to meet falsepositives and false negatives targets, rather than triggering whenfixed thresholds are crossed. In this sense, the detectors that weintroduce are truly adaptive.We then introduce RBS+TRW, an algorithm that combines fan-out rate (RBS)and probability of failure (TRW) of connections to new destinations.RBS+TRW provides a unified framework that at one end acts as a pure RBSand at the other end as pure TRW, and extends RBS's power in detectingworms that scan randomly selected IP addresses