The twilight zone in the parametric evolution of eigenstates: beyond perturbation theory and semiclassics

Considering a quantized chaotic system, we analyze the evolution of its eigenstates as a result of varying a control parameter. As the induced perturbation becomes larger, there is a crossover from a perturbative to a non-perturbative regime, which is reflected in the structural changes of the local density of states. For the first time the {\em full} scenario is explored for a physical system: an Aharonov-Bohm cylindrical billiard. As we vary the magnetic flux, we discover an intermediate twilight regime where perturbative and semiclassical features co-exist. This is in contrast with the {\em simple} crossover from a Lorentzian to a semicircle line-shape which is found in random-matrix models.Comment: 4 pages, 4 figures, improved versio

Dynamic reorganization of vortex matter into partially disordered lattices

We report structural evidence of dynamic reorganization in vortex matter in clean NbSe$_2$ by joint small angle neutron scattering and ac-susceptibility measurements. The application of oscillatory forces in a transitional region near the order-disorder transition results in robust bulk vortex lattice configurations with an intermediate degree of disorder. These dynamically-originated configurations correlate with intermediate pinning responses previously observed, resolving a long standing debate regarding the origin of such responses.Comment: 9 pages, 7 figures. To be published in Physical Review Letter

Photonic heterostructures with Levy-type disorder: statistics of coherent transmission

We study the electromagnetic transmission $T$ through one-dimensional (1D) photonic heterostructures whose random layer thicknesses follow a long-tailed distribution --L\'evy-type distribution. Based on recent predictions made for 1D coherent transport with L\'evy-type disorder, we show numerically that for a system of length $L$ (i) the average $\propto L^\alpha$ for $0 \propto L$ for $1\le\alpha<2$, $\alpha$ being the exponent of the power-law decay of the layer-thickness probability distribution; and (ii) the transmission distribution $P(T)$ is independent of the angle of incidence and frequency of the electromagnetic wave, but it is fully determined by the values of $\alpha$ and $$.Comment: 4 pages, 4 figure

Regularization dependence of the OTOC. Which Lyapunov spectrum is the physical one?

We study the contour dependence of the out-of-time-ordered correlation function (OTOC) both in weakly coupled field theory and in the Sachdev-Ye-Kitaev (SYK) model. We show that its value, including its Lyapunov spectrum, depends sensitively on the shape of the complex time contour in generic weakly coupled field theories. For gapless theories with no thermal mass, such as SYK, the Lyapunov spectrum turns out to be an exception; their Lyapunov spectra do not exhibit contour dependence, though the full OTOCs do. Our result puts into question which of the Lyapunov exponents computed from the exponential growth of the OTOC reflects the actual physical dynamics of the system. We argue that, in a weakly coupled Phi(4) theory, a kinetic theory argument indicates that the symmetric configuration of the time contour, namely the one for which the bound on chaos has been proven, has a proper interpretation in terms of dynamical chaos. Finally, we point out that a relation between these OTOCs and a quantity which may be measured experimentally - the Loschmidt echo - also suggests a symmetric contour configuration, with the subtlety that the inverse periodicity in Euclidean time is half the physical temperature. In this interpretation the chaos bound reads lambda <= 2 pi/beta=pi T-physical

Expected exponential loss for gaze-based video and volume ground truth annotation

Many recent machine learning approaches used in medical imaging are highly reliant on large amounts of image and ground truth data. In the context of object segmentation, pixel-wise annotations are extremely expensive to collect, especially in video and 3D volumes. To reduce this annotation burden, we propose a novel framework to allow annotators to simply observe the object to segment and record where they have looked at with a \$200 eye gaze tracker. Our method then estimates pixel-wise probabilities for the presence of the object throughout the sequence from which we train a classifier in semi-supervised setting using a novel Expected Exponential loss function. We show that our framework provides superior performances on a wide range of medical image settings compared to existing strategies and that our method can be combined with current crowd-sourcing paradigms as well.Comment: 9 pages, 5 figues, MICCAI 2017 - LABELS Worksho

Stochastic simulation of daily rainfall fields conditioned on atmospheric circulation patterns and orographic effects.

The objective of the current work is to present a methodology for simulation of stochastic spatial distributed rainfall fields at the daily time step. For this purpose, we develop a geo-stochastic rainfall generating process (SRGP) to generate spatially distributed rainfall fields at daily time scale, that respect the spatial correlation structure of historically observed precipitation, while taking into account important factors that influence the development of observed spatial patterns. For each day, a spatially distributed rainfall field is generated from a pre-specified SRGP, selected based on atmospheric synoptic conditions relevant for that day. Each SRGP is simulated by applying the concept of double kriging, as the product of the spatial amount of rainfall and the spatial occurrence of rainfall by sequential simulation (sequential Gaussian simulation and sequential indicator simulation respectively). The SRGP can account for spatial rainfall nonstationarity related to orographic effects, and can be incorporated as part of a downscaling technique in the context of climate change impact studies. A case study for the Upper Guadiana basin (Spain) is presented that shows the ability of the method to reproduce various spatio-temporal characteristics of precipitation.Peer ReviewedPostprint (published version

Molecular Mechanism and Potential Targets for Blocking HPV-Induced Lesion Development

Persistent infection with high-risk HPV is the etiologic agent associated with the development of cervical cancer (CC) development. However, environmental, social, epidemiological, genetic, and host factors may have a joint influence on the risk of disease progression. Cervical lesions caused by HPV infection can be removed naturally by the host immune response and only a small percentage may progress to cancer; thus, the immune response is essential for the control of precursor lesions and CC. We present a review of recent research on the molecular mechanisms that allow HPV-infected cells to evade immune surveillance and potential targets of molecular therapy to inhibit tumor immune escape

Chaotic Waveguide-Based Resonators for Microlasers

We propose the construction of highly directional emission microlasers using two-dimensional high-index semiconductor waveguides as {\it open} resonators. The prototype waveguide is formed by two collinear leads connected to a cavity of certain shape. The proposed lasing mechanism requires that the shape of the cavity yield mixed chaotic ray dynamics so as to have the appropiate (phase space) resonance islands. These islands allow, via Heisenberg's uncertainty principle, the appearance of quasi bound states (QBS) which, in turn, propitiate the lasing mechanism. The energy values of the QBS are found through the solution of the Helmholtz equation. We use classical ray dynamics to predict the direction and intensity of the lasing produced by such open resonators for typical values of the index of refraction.Comment: 5 pages, 5 figure

Effect of Yb concentration on the resistivity and lifetime of CdTe:Ge:Yb codoped crystals

The resistivity and electron lifetime of CdTe:Ge:Yb crystals are reported, demonstrating that the effect of Yb concentration is crucial for accurate electrical compensation. It is also demonstrated that the codoping of CdTe with Ge as deep donor and with Yb as rare-earth element could be a promising way to obtain semiinsulating CdTe crystals with good transport properties. High resistivity 5 10 9 cm and lifetime 9 s were obtained, thus confirming the beneficial effect of rare-earth dopingThis work has been partly supported by the projects CAM SENSORCDT S-0505/MAT/0209, CAM FOTOFLEX S-0505/ENE-123, and EU FP6 PHOLOGIC 017158. E.S. also acknowledges the Spanish MEC for the fellowship FPU 2003-1388.Peer reviewe