Hole burning in a nanomechanical resonator coupled to a Cooper pair box

We propose a scheme to create holes in the statistical distribution of excitations of a nanomechanical resonator. It employs a controllable coupling between this system and a Cooper pair box. The success probability and the fidelity are calculated and compared with those obtained in the atom-field system via distinct schemes. As an application we show how to use the hole-burning scheme to prepare (low excited) Fock states.Comment: 7 pages, 10 figure

WZW action in odd dimensional gauge theories

It is shown that Wess-Zumino-Witten (WZW) type actions can be constructed in odd dimensional space-times using Wilson line or Wilson loop. WZW action constructed using Wilson line gives anomalous gauge variations and the WZW action constructed using Wilson loop gives anomalous chiral transformation. We show that pure gauge theory including Yang-Mills action, Chern-Simons action and the WZW action can be defined in odd dimensional space-times with even dimensional boundaries. Examples in 3D and 5D are given. We emphasize that this offers a way to generalize gauge theory in odd dimensions. The WZW action constructed using Wilson line can not be considered as action localized on boundary space-times since it can give anomalous gauge transformations on separated boundaries. We try to show that such WZW action can be obtained in the effective theory when making localized chiral fermions decouple.Comment: 19 pages, text shortened, reference added. Version to appear in PR

On peaked solitary waves of Degasperis - Procesi equation

The Degasperis - Procesi (DP) equation describing the propagation of shallow water waves contains a physical parameter $\omega$, and it is well-known that the DP equation admits solitary waves with a peaked crest when $\omega = 0$. In this article, we illustrate, for the first time, that the DP equation admits peaked solitary waves even when $\omega \neq 0$. This is helpful to enrich our knowledge and deepen our understandings about peaked solitary waves of the DP equation.Comment: 11 pages, 3 figures, accepted by Science China - Physics, Mechanics & Astronom

Comparison of a general series expansion method and the homotopy analysis method

A simple analytic tool namely the general series expansion method is proposed to find the solutions for nonlinear differential equations. By choosing a set of suitable basis functions $\{e_n(t,t_0)\}_{n=0}^{+\infty}$ such that the solution to the equation can be expressed by $u(t)=\sum_{n=0}^{+\infty}c_ne_n(t,t_0)$. In general, $t_0$ can control and adjust the convergence region of the series solution such that our method has the same effect as the homotopy analysis method proposed by Liao, but our method is more simple and clear. As a result, we show that the secret parameter $h$ in the homotopy analysis methods can be explained by using our parameter $t_0$. Therefore, our method reveals a key secret in the homotopy analysis method. For the purpose of comparison with the homotopy analysis method, a typical example is studied in detail.Comment: 8 page

Flow Equations for U_k and Z_k

By considering the gradient expansion for the wilsonian effective action S_k of a single component scalar field theory truncated to the first two terms, the potential U_k and the kinetic term Z_k, I show that the recent claim that different expansion of the fluctuation determinant give rise to different renormalization group equations for Z_k is incorrect. The correct procedure to derive this equation is presented and the set of coupled differential equations for U_k and Z_k is definitely established.Comment: 5 page

Association of Social Support and Cognitive Aging Modified by Sex and Relationship Type: A Prospective Investigation in the English Longitudinal Study of Ageing

We examined whether between-person differences (PM) and within-person change in levels of social support were associated with age-related cognitive decline, and whether these associations varied by sex and by relationship type. Executive function and memory scores over eight years (2002-2010) were analysed by mixture models (10,241 adults’ aged≥50 years) in the English Longitudinal Study of Ageing. PM and within-person change in positive social support and negative social support were independently associated with cognitive decline in different ways by sex and relationship type. Among men, higher-than-others positive social support from spouse/partner was associated with slower cognitive decline (executive function: βPM*time-in-study = 0.005, 95%CI: 0.001, 0.010; memory: βPM*time-in-study = 0.006, 95%CI 0.000, 0.012); whereas high negative social support from all relationship types was associated with accelerated decline in executive function (all-relationships-combined: βPM* time-in-study = -0.005, 95%CI: -0.008, -0.002). For women, higher-than-others positive social support from children (β=0.037, 95%CI: 0.010, 0.064) and friends (β=0.115, 95%CI: 0.081, 0.150) but not from spouse/partner (β=-0.034, 95%CI: -0.059, -0.009) or extended family (β=-0.035, 95%CI: -0.064, -0.006) was associated with higher executive function. Associations between social support and age-related cognitive decline vary across different relationship types for men and women

Towards Semantic Fast-Forward and Stabilized Egocentric Videos

The emergence of low-cost personal mobiles devices and wearable cameras and the increasing storage capacity of video-sharing websites have pushed forward a growing interest towards first-person videos. Since most of the recorded videos compose long-running streams with unedited content, they are tedious and unpleasant to watch. The fast-forward state-of-the-art methods are facing challenges of balancing the smoothness of the video and the emphasis in the relevant frames given a speed-up rate. In this work, we present a methodology capable of summarizing and stabilizing egocentric videos by extracting the semantic information from the frames. This paper also describes a dataset collection with several semantically labeled videos and introduces a new smoothness evaluation metric for egocentric videos that is used to test our method.Comment: Accepted for publication and presented in the First International Workshop on Egocentric Perception, Interaction and Computing at European Conference on Computer Vision (EPIC@ECCV) 201

A blind deconvolution approach to recover effective connectivity brain networks from resting state fMRI data

A great improvement to the insight on brain function that we can get from fMRI data can come from effective connectivity analysis, in which the flow of information between even remote brain regions is inferred by the parameters of a predictive dynamical model. As opposed to biologically inspired models, some techniques as Granger causality (GC) are purely data-driven and rely on statistical prediction and temporal precedence. While powerful and widely applicable, this approach could suffer from two main limitations when applied to BOLD fMRI data: confounding effect of hemodynamic response function (HRF) and conditioning to a large number of variables in presence of short time series. For task-related fMRI, neural population dynamics can be captured by modeling signal dynamics with explicit exogenous inputs; for resting-state fMRI on the other hand, the absence of explicit inputs makes this task more difficult, unless relying on some specific prior physiological hypothesis. In order to overcome these issues and to allow a more general approach, here we present a simple and novel blind-deconvolution technique for BOLD-fMRI signal. Coming to the second limitation, a fully multivariate conditioning with short and noisy data leads to computational problems due to overfitting. Furthermore, conceptual issues arise in presence of redundancy. We thus apply partial conditioning to a limited subset of variables in the framework of information theory, as recently proposed. Mixing these two improvements we compare the differences between BOLD and deconvolved BOLD level effective networks and draw some conclusions