Stochastic integrals for spde's: a comparison

We present the Walsh theory of stochastic integrals with respect to martingale measures, alongside of the Da Prato and Zabczyk theory of stochastic integrals with respect to Hilbert-space-valued Wiener processes and some other approaches to stochastic integration, and we explore the links between these theories. We then show how each theory can be used to study stochastic partial differential equations, with an emphasis on the stochastic heat and wave equations driven by spatially homogeneous Gaussian noise that is white in time. We compare the solutions produced by the different theories

All bipartite entangled states display some hidden nonlocality

We show that a violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality can be demonstrated in a certain kind of Bell experiment for all bipartite entangled states. Our protocol allows local filtering measurements and involves shared ancilla states that do not themselves violate CHSH. Our result follows from two main steps. We first provide a simple characterization of the states that violate the CHSH-inequality after local filtering operations in terms of witness-like operators. Second, we prove that for each entangled state $\sigma$, there exists another state $\rho$ not violating CHSH, such that $\rho\otimes\sigma$ violates CHSH. Hence, in this scenario, $\sigma$ cannot be substituted by classical correlations without changing the statistics of the experiment; we say that $\sigma$ is not simulable by classical correlations and our result is that entanglement is equivalent to non-simulability.Comment: 5 pages, 1 figur

From Bell's Theorem to Secure Quantum Key Distribution

Any Quantum Key Distribution (QKD) protocol consists first of sequences of measurements that produce some correlation between classical data. We show that these correlation data must violate some Bell inequality in order to contain distillable secrecy, if not they could be produced by quantum measurements performed on a separable state of larger dimension. We introduce a new QKD protocol and prove its security against any individual attack by an adversary only limited by the no-signaling condition.Comment: 5 pages, 2 figures, REVTEX

More than an adaptor molecule: The emerging role of tRNA in cell signaling and disease

This FEBS Letters ‘FOCUS ON’ series of short reviews on tRNA captures the essence of the Barcelona BioMed Conference on Gene Translation: Fidelity and Quality Control, which was held at the Institut d’Estudis Catalans in Barcelona on December 2–4, 2013. This meeting was powered by the dramatic resurgence of interest in tRNA biochemistry following the realization that tRNA is much more than a simple adaptor of the genetic code

The association between unemployment trajectories and alcohol consumption patterns. Evidence from a large prospective cohort in The Netherlands

Unemployment is expected to influence alcohol consumption, but studies show mixed results, partly because most studies concentrate on current employment status. However, unemployment could be particularly consequential if it is part of a trajectory of employment precariousness. Moreover, the association between unemployment and alcohol consumption may not be homogeneous across the population, but differ by subgroups (e.g. socioeconomic status). This study longitudinally analyses the association between different employment trajectories and alcohol consumption, and examines if the association is moderated by socioeconomic status (SES), partner status, age and gender. Four waves of data of the Lifelines Cohort study are used. Sample consists of individuals from 18-50 years old, active in the labor market (n = 104,766) from the northern provinces of the Netherlands. Employment trajectories are defined by employment status in each wave, duration of unemployment, and number of exposures to unemployment. Drinking patterns are divided into "abstainers", "moderate drinking" (1.5 drinks/day) and "binge drinking" (>5 drinks/occasion; 4 for women). The associations are estimated with multinomial logistic regression models. Results show that recent, long-term unemployment (> 6 months) is associated with higher rates of heavy drinking (RRR = 1.26 [95 % CI 1.03-1.54]), whereas short-term unemployment does not show any association with the outcome. Being continuously unemployed throughout the observation period shows a strong association with binge drinking (RRR = 1.43 [95 % CI 1.06-1.93]), as well as reporting 2 or more long unemployment spells (RRR = 1.49 [95 % CI 1.21-1.83]). The group of abstainers (77.95 % women) have significantly lower SES, and poorer health than their peers. For some individuals, recent unemployment increases the likelihood for abstinence (RRR = 1.23 [95 % CI 1.00-1.51]). Evidence suggests that length of unemployment is key in order to grasp its effects in terms of changing drinking patterns

Spatiotemporal discrete multicolor solitons

We have found various families of two-dimensional spatiotemporal solitons in quadratically nonlinear waveguide arrays. The families of unstaggered odd, even and twisted stationary solutions are thoroughly characterized and their stability against perturbations is investigated. We show that the twisted and even solutions display instability, while most of the odd solitons show remarkable stability upon evolution.Comment: 18 pages,7 figures. To appear in Physical Review

Enhanced soliton interactions by inhomogeneous nonlocality and nonlinearity

We address the interactions between optical solitons in the system with longitudinally varying nonlocality degree and nonlinearity strength. We consider a physical model describing light propagation in nematic liquid crystals featuring a strongly nonlocal nonlinear response. We reveal that the variation of the nonlocality and nonlinearity along the propagation direction can substantially enhance or weaken the interaction between out-of-phase solitons. This phenomenon manifests itself as a slowdown or acceleration of the soliton collision dynamics in one-dimensional geometries or of the soliton spiraling rate in bulk media. Therefore, one finds that by engineering the nonlocality and nonlinearity variation rate one can control the output soliton location.Comment: 22 pages, 5 figures, to appear in Physical Review