201 research outputs found
The spectrum of lattice QCD with staggered fermions at strong coupling
Using 4 flavors of staggered fermions at infinite gauge coupling, we compare
various analytic results for the hadron spectrum with exact Monte Carlo
simulations. Agreement with Ref. \cite{Martin_etal} is very good, at the level
of a few percent.
Our results give credence to a discrepancy between the baryon mass and the
critical chemical potential, for which baryons fill the lattice at zero
temperature and infinite gauge coupling. Independent determinations of the
latter set it at about 30% less than the baryon mass. One possible explanation
is that the nuclear attraction becomes strong at infinite gauge coupling.Comment: 11 pages, 3 figure
Rotating With Rotated Text: A Natural Behavior Approach to Investigating Cognitive Offloading
On Picturing a Candle: The Prehistory of Imagery Science
The past 25 years have seen a rapid growth of knowledge about brain mechanisms involved in visual mental imagery. These advances have largely been made independently of the long history of philosophical – and even psychological – reckoning with imagery and its parent concept ‘imagination’. We suggest that the view from these empirical findings can be widened by an appreciation of imagination’s intellectual history, and we seek to show how that history both created the conditions for – and presents challenges to – the scientific endeavor. We focus on the neuroscientific literature’s most commonly used task – imagining a concrete object – and, after sketching what is known of the neurobiological mechanisms involved, we examine the same basic act of imagining from the perspective of several key positions in the history of philosophy and psychology. We present positions that, firstly, contextualize and inform the neuroscientific account, and secondly, pose conceptual and methodological challenges to the scientific analysis of imagery. We conclude by reflecting on the intellectual history of visualization in the light of contemporary science, and the extent to which such science may resolve long-standing theoretical debates
Strongly Correlated Electrons on a Silicon Surface: Theory of a Mott Insulator
We demonstrate theoretically that the electronic ground state of the
potassium-covered Si(111)-B surface is a Mott insulator, explicitly
contradicting band theory but in good agreement with recent experiments. We
determine the physical structure by standard density-functional methods, and
obtain the electronic ground state by exact diagonalization of a many-body
Hamiltonian. The many-body conductivity reveals a Brinkman-Rice metal-insulator
transition at a critical interaction strength; the calculated interaction
strength is well above this critical value.Comment: 4 pages; 4 figures included in text; Revte
Action observation can prime visual object recognition
Observing an action activates action representations in the motor system. Moreover, the representations of manipulable objects are closely linked to the motor systems at a functional and neuroanatomical level. Here, we investigated whether action observation can facilitate object recognition using an action priming paradigm. As prime stimuli we presented short video movies showing hands performing an action in interaction with an object (where the object itself was always removed from the video). The prime movie was followed by a (briefly presented) target object affording motor interactions that are either similar (congruent condition) or dissimilar (incongruent condition) to the prime action. Participants had to decide whether an object name shown after the target picture corresponds with the picture or not (picture–word matching task). We found superior accuracy for prime–target pairs with congruent as compared to incongruent actions across two experiments. Thus, action observation can facilitate recognition of a manipulable object typically involving a similar action. This action priming effect supports the notion that action representations play a functional role in object recognition
Reading between Eye Saccades
Background: Skilled adult readers, in contrast to beginners, show no or little increase in reading latencies as a function of the number of letters in words up to seven letters. The information extraction strategy underlying such efficiency in word identification is still largely unknown, and methods that allow tracking of the letter information extraction through time between eye saccades are needed to fully address this question. Methodology/Principal Findings: The present study examined the use of letter information during reading, by means of the Bubbles technique. Ten participants each read 5,000 five-letter French words sampled in space-time within a 200 ms window. On the temporal dimension, our results show that two moments are especially important during the information extraction process. On the spatial dimension, we found a bias for the upper half of words. We also show for the first time that letter positions four, one, and three are particularly important for the identification of five-letter words. Conclusions/Significance: Our findings are consistent with either a partially parallel reading strategy or an optimal serial reading strategy. We show using computer simulations that this serial reading strategy predicts an absence of a wordlength effect for words from four- to seven letters in length. We believe that the Bubbles technique will play an importan
Catalytic dehydrogenative Si–N coupling of pyrroles, indoles, carbazoles as well as anilines with hydrosilanes without added base
- …