Predicting (in)correctly: listeners rapidly use unexpected information to revise their predictions

Comprehenders can incorporate rich contextual information to predict upcoming input on the fly, and cues that conflict with their predictions are quickly detected. The present study examined whether and how comprehenders may revise their existing predictions upon encountering a prediction-inconsistent cue. We took advantage of the rich classifier system in Mandarin Chinese and tracked participants’ eye-movements as they listened to sentences in which the final noun is preceded by a classifier which was either compatible with the most expected noun, incompatible with the most expected noun but indicative of another contextually suitable noun, or uninformative. We found that, upon hearing a prediction-inconsistent classifier, listeners quickly directed their eye gaze away from the originally expected object and immediately onto the (initially) unexpected but contextually suitable object. This provides initial evidence that listeners can quickly use prediction-mismatching cues to revise their existing predictions on the fly

Pinned modes in two-dimensional lossy lattices with local gain and nonlinearity

We introduce a system with one or two amplified nonlinear sites ("hot spots", HSs) embedded into a two-dimensional linear lossy lattice. The system describes an array of evanescently coupled optical or plasmonic waveguides, with gain applied at selected HS cores. The subject of the analysis is discrete solitons pinned to the HSs. The shape of the localized modes is found in quasi-analytical and numerical forms, using a truncated lattice for the analytical consideration. Stability eigenvalues are computed numerically, and the results are supplemented by direct numerical simulations. In the case of self-focusing nonlinearity, the modes pinned to a single HS are stable or unstable when the nonlinearity includes the cubic loss or gain, respectively. If the nonlinearity is self-defocusing, the unsaturated cubic gain acting at the HS supports stable modes in a small parametric area, while weak cubic loss gives rise to a bistability of the discrete solitons. Symmetric and antisymmetric modes pinned to a symmetric set of two HSs are considered too.Comment: Philosophical Transactions of the Royal Society A, in press (a special issue on "Localized structures in dissipative media"

Anomalous kinetics of attractive A+B→0A+B \to 0 reactions

We investigate the kinetics of $A+B \to 0$ reaction with the local attractive interaction between opposite species in one spatial dimension. The attractive interaction leads to isotropic diffusions inside segregated single species domains, and accelerates the reactions of opposite species at the domain boundaries. At equal initial densities of $A$ and $B$, we analytically and numerically show that the density of particles ($\rho$), the size of domains ($\ell$), the distance between the closest neighbor of same species ($\ell_{AA}$), and the distance between adjacent opposite species ($\ell_{AB}$) scale in time as $\rho \sim t^{-1/3}$, $\ell_{AA} \sim t^{1/3}$, and $\ell \sim \ell_{AB} \sim t^{2/3}$ respectively. These dynamical exponents form a new universality class distinguished from the class of uniformly driven systems of hard-core particles.Comment: 4 pages, 4 figure

Robust effects of predictability across experimental contexts: Evidence from event-related potentials

Many experiments have shown that comprehenders can generate predictions about upcoming inputs on the fly, but relatively little is known about whether and how comprehenders' sensitivity to predictability may be modulated by the experimental context. The present study used event-related potentials (ERPs) in two experiments to ask whether changing the overall predictive validity of the stimuli will affect comprehenders' brain responses to predictable as well as unpredictable words by manipulating the filler sentences, which made up 50% of the stimuli in each experiment. Contrary to the prediction that predictable words should be processed more easily and elicit a smaller N400 response in a more prediction-encouraging experimental context, we found that participants' N400 response to predictable as well as unpredictable words was smaller when the overall predictive validity of the stimuli was low (that is, when the filler items were incongruous compared to when they were predictable). Further, even though the use of different filler sentences did modulate comprehenders' ERP and behavioural responses, it did not modulate the effect of target word predictability on participants' ERP responses at all. We take the present findings to suggest that healthy young adults’ brain responses are inherently sensitive to the predictability of the incoming linguistic stimuli, and that this robust sensitivity can be observed regardless of the make-up of the experimental stimuli

Epidermal transient receptor potential vanilloid 1 in idiopathic small nerve fibre disease, diabetic neuropathy and healthy human subjects

10.1111/j.1365-2559.2007.02851.xHistopathology515674-68

Calculation of pure dephasing for excitons in quantum dots

Pure dephasing of an exciton in a small quantum dot by optical and acoustic phonons is calculated using the ``independent boson model''. Considering the case of zero temperature the dephasing is shown to be only partial which manifests itself in the polarization decaying to a finite value. Typical dephasing times can be assigned even though the spectra exhibits strongly non-Lorentzian line shapes. We show that the dephasing from LO phonon scattering, occurs on a much larger time scale than that of dephasing due to acoustic phonons which for low temperatures are also a more efficient dephasing mechanism. The typical dephasing time is shown to strongly depend on the quantum dot size whereas the electron phonon ``coupling strength'' and external electric fields tend mostly to effect the residual coherence. The relevance of the dephasing times for current quantum information processing implementation schemes in quantum dots is discussed

Macroscopic objects in quantum mechanics: A combinatorial approach

Why we do not see large macroscopic objects in entangled states? There are two ways to approach this question. The first is dynamic: the coupling of a large object to its environment cause any entanglement to decrease considerably. The second approach, which is discussed in this paper, puts the stress on the difficulty to observe a large scale entanglement. As the number of particles n grows we need an ever more precise knowledge of the state, and an ever more carefully designed experiment, in order to recognize entanglement. To develop this point we consider a family of observables, called witnesses, which are designed to detect entanglement. A witness W distinguishes all the separable (unentangled) states from some entangled states. If we normalize the witness W to satisfy |tr(W\rho)| \leq 1 for all separable states \rho, then the efficiency of W depends on the size of its maximal eigenvalue in absolute value; that is, its operator norm ||W||. It is known that there are witnesses on the space of n qbits for which ||W|| is exponential in n. However, we conjecture that for a large majority of n-qbit witnesses ||W|| \leq O(\sqrt{n logn}). Thus, in a non ideal measurement, which includes errors, the largest eigenvalue of a typical witness lies below the threshold of detection. We prove this conjecture for the family of extremal witnesses introduced by Werner and Wolf (Phys. Rev. A 64, 032112 (2001)).Comment: RevTeX, 14 pages, some additions to the published version: A second conjecture added, discussion expanded, and references adde

Eye-tracking evidence for active gap-filling regardless of dependency length

Previous work on real-time sentence processing has established that comprehenders build and interpret filler-gap dependencies without waiting for unambiguous evidence about the actual location of the gap ("active gap-filling") as long as such dependencies are grammatically licensed. However, this generalisation was called into question by recent findings in a self-paced reading experiment by Wagers and Phillips, which may be taken to show that comprehenders do not interpret the filler at the posited gap when the dependency spans a longer distance. In the present study, we aimed to replicate these findings in an eye-tracking experiment with better controlled materials and increased statistical power. Crucially, we found clear evidence for active gap-filling across all levels of dependency length. This diverges from Wagers and Phillips's findings but is in line with the long-standing generalisation that comprehenders build and interpret filler-gap dependencies predictively as long as they are grammatically licensed. We found that the effect became smaller in the long dependency conditions in the post-critical region, which suggests the weaker effect in the long dependency conditions may have been undetected in Wagers and Phillips's study due to insufficient statistical power and/or the use of a self-paced reading paradigm

Dynamics of two laterally coupled semiconductor lasers: strong- and weak-coupling theory.

Copyright © 2008 The American Physical SocietyThe stability and nonlinear dynamics of two semiconductor lasers coupled side to side via evanescent waves are investigated by using three different models. In the composite-cavity model, the coupling between the lasers is accurately taken into account by calculating electric field profiles (composite-cavity modes) of the whole coupled-laser system. A bifurcation analysis of the composite-cavity model uncovers how different types of dynamics, including stationary phase-locking, periodic, quasiperiodic, and chaotic intensity oscillations, are organized. In the individual-laser model, the coupling between individual lasers is introduced phenomenologically with ad hoc coupling terms. Comparison with the composite-cavity model reveals drastic differences in the dynamics. To identify the causes of these differences, we derive a coupled-laser model with coupling terms which are consistent with the solution of the wave equation and the relevant boundary conditions. This coupled-laser model reproduces the dynamics of the composite-cavity model under weak-coupling conditions