Dicke simulators with emergent collective quantum computational abilities

Using an approach inspired from Spin Glasses, we show that the multimode disordered Dicke model is equivalent to a quantum Hopfield network. We propose variational ground states for the system at zero temperature, which we conjecture to be exact in the thermodynamic limit. These ground states contain the information on the disordered qubit-photon couplings. These results lead to two intriguing physical implications. First, once the qubit-photon couplings can be engineered, it should be possible to build scalable pattern-storing systems whose dynamics is governed by quantum laws. Second, we argue with an example how such Dicke quantum simulators might be used as a solver of "hard" combinatorial optimization problems.Comment: 5+2 pages, 2 figures. revisited in the exposition and supplementary added. Comments are welcom

Some Remarks on the Division of Cognitive Labor

Since the publication of Kitcher’s influential paper The Division of Cognitive Labor, some philosophers wondered about these two related issues: (1) which is the optimal distribution of cognitive efforts among rival methods within a scientific community?, and (2) whether and how can a community achieve such an optimal distribution? Though not committing to any specific answer to question (1), I claim that issue (2) does not depend exclusively on an invisible hand like mechanism, since both intra-scientific and extra-scientific institutions may play a major role. Finally, I examine some practical difficulties of reallocating scientists from a method to another, which leads to stress the importance of well-planned training and recruitment

Seeing through the shades of situated affectivity. Sunglasses as a socio-affective artifact

Debates on situated affectivity have mainly focused on tools that exert some positive influence on affective experience. Far less attention has been paid to artifacts that interact with the expression of affect, or to those that exert some negative influence. To shed light on that shadowy corner of our affective social lives, I describe the workings of an atypical socio-affective artifact, namely, sunglasses. Drawing on insights from psychology and other social sciences, I construe sunglasses as a social shield that helps us block spontaneous emotional expressions, as well as affecting other social processes that heavily depend on the eye region: gaze direction detection, identity recognition, and the sense of intimacy afforded by eye contact

Bibliometric indicators: the origin of their log-normal distribution and why they are not a reliable proxy for an individual scholar’s talent

There is now compelling evidence that the statistical distributions of extensive individual bibliometric indicators collected by a scholar, such as the number of publications or the total number of citations, are well represented by a Log-Normal function when homogeneous samples are considered. A Log-Normal distribution function is the normal distribution for the logarithm of the variable. In linear scale it is a highly skewed distribution with a long tail in the high productivity side. We are still lacking a detailed and convincing ab-initio model able to explain observed Log-Normal distributions-this is the gap this paper sets out to fill. Here, we propose a general explanation of the observed evidence by developing a straightforward model based on the following simple assumptions: (1) the materialist principle of the natural equality of human intelligence, (2) the success breeds success effect, also known as Merton effect, which can be traced back to the Gospel parables about the Talents (Matthew) and Minas (Luke), and, (3) the recognition and reputation mechanism. Building on these assumptions we propose a distribution function that, although mathematically not identical to a Log-Normal distribution, shares with it all its main features. Our model well reproduces the empirical distributions, so the hypotheses at the basis of the model are not falsified. Therefore the distributions of the bibliometric parameters observed might be the result of chance and noise (chaos) related to multiplicative phenomena connected to a publish or perish inflationary mechanism, led by scholars' recognition and reputations. In short, being a scholar in the right tail or in the left tail of the distribution could have very little connection to her/his merit and achievements. This interpretation might cast some doubts on the use of the number of papers and/or citations as a measure of scientific achievements. A tricky issue seems to emerge, that is: what then do bibliometric indicators really measure? This issue calls for deeper investigations into the meaning of bibliometric indicators. This is an interesting and intriguing topic for further research to be carried out within a wider interdisciplinary investigation of the science of science, which may include elements and investigation tools from philosophy, psychology and sociology

A two-phase gradient method for quadratic programming problems with a single linear constraint and bounds on the variables

We propose a gradient-based method for quadratic programming problems with a single linear constraint and bounds on the variables. Inspired by the GPCG algorithm for bound-constrained convex quadratic programming [J.J. Mor\'e and G. Toraldo, SIAM J. Optim. 1, 1991], our approach alternates between two phases until convergence: an identification phase, which performs gradient projection iterations until either a candidate active set is identified or no reasonable progress is made, and an unconstrained minimization phase, which reduces the objective function in a suitable space defined by the identification phase, by applying either the conjugate gradient method or a recently proposed spectral gradient method. However, the algorithm differs from GPCG not only because it deals with a more general class of problems, but mainly for the way it stops the minimization phase. This is based on a comparison between a measure of optimality in the reduced space and a measure of bindingness of the variables that are on the bounds, defined by extending the concept of proportioning, which was proposed by some authors for box-constrained problems. If the objective function is bounded, the algorithm converges to a stationary point thanks to a suitable application of the gradient projection method in the identification phase. For strictly convex problems, the algorithm converges to the optimal solution in a finite number of steps even in case of degeneracy. Extensive numerical experiments show the effectiveness of the proposed approach.Comment: 30 pages, 17 figure

Social Epistemology at Work: from Philosophical Theory to Policy Advice

Introductio

Design and Performance of a High Temperature Superconducting Axial Flux Generator

In this paper, a high temperature axial flux (HTSAF) generator is presented. In this generator the excitation of the generator is obtained by using some high temperature superconducting magnets. In order to reduce the negative effects of vibrations, the excitation is located on the stationary part of the generator. Starting, running and endurance tests of the machine are presented

Evaluation of the Potential Energy from Wave Motion on the Sicilian coast

The purpose of this articles is quantitatively evaluate the wave climate variations of the northern Sicilian coasts. In particular, the objective of the study is Castellammare del Golfo, a marine site between Trapani and Palermo. In particular in this research, the wave energy of the Sicily has been studied by an analysis of wave data carried out in a 10- year period, using the measurements of buoyant of RON. The north-western and southern coasts of Sicily have a lower potential with average wave power ranging between 2.5 and 6.5 kW/m