Semilinear response for the heating rate of cold atoms in vibrating traps

The calculation of the heating rate of cold atoms in vibrating traps requires a theory that goes beyond the Kubo linear response formulation. If a strong "quantum chaos" assumption does not hold, the analysis of transitions shows similarities with a percolation problem in energy space. We show how the texture and the sparsity of the perturbation matrix, as determined by the geometry of the system, dictate the result. An improved sparse random matrix model is introduced: it captures the essential ingredients of the problem, and leads to a generalized variable range hopping picture.Comment: 6 pages, 6 figures, improved version to be published in Europhysics Letter

Stochastic memory: memory enhancement due to noise

There are certain classes of resistors, capacitors and inductors that, when subject to a periodic input of appropriate frequency, develop hysteresis loops in their characteristic response. Here, we show that the hysteresis of such memory elements can also be induced by white noise of appropriate intensity even at very low frequencies of the external driving field. We illustrate this phenomenon using a physical model of memory resistor realized by $\mathrm{TiO_2}$ thin films sandwiched between metallic electrodes, and discuss under which conditions this effect can be observed experimentally. We also discuss its implications on existing memory systems described in the literature and the role of colored noise.Comment: 5 pages, 4 figure

Diffractive energy spreading and its semiclassical limit

We consider driven systems where the driving induces jumps in energy space: (1) particles pulsed by a step potential; (2) particles in a box with a moving wall; (3) particles in a ring driven by an electro-motive-force. In all these cases the route towards quantum-classical correspondence is highly non-trivial. Some insight is gained by observing that the dynamics in energy space, where $n$ is the level index, is essentially the same as that of Bloch electrons in a tight binding model, where $n$ is the site index. The mean level spacing is like a constant electric field and the driving induces long range hopping 1/(n-m).Comment: 19 pages, 11 figs, published version with some improved figure

Relationship Between Excessive Gestational Weight Gain and Neonatal Adiposity in Women With Mild Gestational Diabetes Mellitus

OBJECTIVE: To evaluate the relationships between excessive gestational weight gain, neonatal adiposity, and adverse obstetric outcomes in women with mild gestational diabetes mellitus (GDM). METHODS: This is a secondary analysis of a multicenter randomized clinical trial of women with mild GDM. Based on self-reported prepregnancy body weight, gestational weight gain was categorized as excessive if it was greater than 2009 Institute of Medicine guidelines. Maternal outcomes and neonatal anthropomorphic characteristics were compared between women with excessive weight gain and those without excessive weight gain. Multiple linear and logistic regression analyses were performed to adjust for confounding factors. RESULTS: We studied 841 women who participated in the main trial and had prepregnancy BMI and delivery information available (n= 431 treatment group, n= 410 no treatment). After adjustment for factors including treatment and prepregnancy BMI, excessive weight gain remained associated with LGA (aOR 2.94, 95% CI 1.81-4.93), BW > 4000 grams (aOR 2.56, 95% CI 1.54-4.40), preeclampsia (aOR 2.96, 95% CI 1.35-7.03) and cesarean delivery for labor arrest (aOR 2.37, 95% CI 1.30-4.44). In addition, excessive weight gain was independently associated with increased total neonatal fat (p < 0.001) and birth weight (p < 0.001). CONCLUSION: In women with both treated and untreated mild GDM, excessive gestational weight gain was independently associated with both greater birth weight and adiposity