Quantum work statistics, Loschmidt echo and information scrambling.

A universal relation is established between the quantum work probability distribution of an isolated driven quantum system and the Loschmidt echo dynamics of a two-mode squeezed state. When the initial density matrix is canonical, the Loschmidt echo of the purified double thermofield state provides a direct measure of information scrambling and can be related to the analytic continuation of the partition function. Information scrambling is then described by the quantum work statistics associated with the time-reversal operation on a single copy, associated with the sudden negation of the system Hamiltonian.

Quantum Speed Limits across the Quantum-to-Classical Transition.

Quantum speed limits set an upper bound to the rate at which a quantum system can evolve. Adopting a phase-space approach, we explore quantum speed limits across the quantum-to-classical transition and identify equivalent bounds in the classical world. As a result, and contrary to common belief, we show that speed limits exist for both quantum and classical systems. As in the quantum domain, classical speed limits are set by a given norm of the generator of time evolution.

Quantum Simulation of Generic Many-Body Open System Dynamics Using Classical Noise.

We introduce a scheme for the quantum simulation of many-body decoherence based on the unitary evolution of a stochastic Hamiltonian. Modulating the strength of the interactions with stochastic processes, we show that the noise-averaged density matrix simulates an effectively open dynamics governed by k-body Lindblad operators. Markovian dynamics can be accessed with white-noise fluctuations; non-Markovian dynamics requires colored noise. The time scale governing the fidelity decay under many-body decoherence is shown to scale as N^{-2k} with the system size N. Our proposal can be readily implemented in a variety of quantum platforms including optical lattices, superconducting circuits, and trapped ions.

[Pleasure: Neurobiological conception and Freudian conception]. / Le plaisir : conception neurobiologique et conception freudienne.

Despite many controversies the debate between psychoanalysis and neuroscience remains intense, all the more since the Freudian theory stands as a reference for a number of medical practitioners and faculty psychiatrists, at least in France. Instead of going on arguing we think that it may be more constructive to favour dialogue through the analysis of a precise concept developed in each discipline. The Freudian theory of pleasure, because it is based on biological principles, appears an appropriate topic to perform this task. In this paper, we aim at comparing Freud's propositions to those issued from recent findings in Neuroscience. Like all emotions, pleasure is acknowledged as a motivating factor in contemporary models. Pleasure can indeed be either rewarding when it follows satisfaction, or incentive when it reinforces behaviours. The Freudian concept of pleasure is more univocal. In Freud's theory, pleasure is assumed to be the result of the discharge of the accumulated excitation which will thus reduce the tension. This quantitative approach corresponds to the classical scheme that associates satisfaction and pleasure. Satisfaction of a need would induce both a decrease in tension and the development of pleasure. However, clinical contradictions to this model, such as the occasional co-existence between pleasure and excitation, drove Freud to suggest different theoretical reversals. Freud's 1905 publication, which describes how preliminary sexual pleasures contribute to an increased excitation and a sexual satisfaction, is the only analysis which provides an adapted answer to the apparent paradox of pleasure and excitation co-existence. Studies on the neurobiological mechanisms responsible for the development of pleasure may help to fill this gap in the Freudian theory. Activity of the mesolimbic dopaminergic pathway is strongly associated with the reward system. Experimental studies performed in animals have shown that increased dopaminergic activity in the ventral tegmental area (VTA, where dopaminergic cell bodies lie) results either from an unexpected reward or, after recognition of the reward characteristics, from the anticipation of the reward. Therefore, anticipation of a satisfaction activates neurochemical pleasure mechanisms and reinforces behaviour which facilitates its obtention. In this way, pleasure contributes to an increased level of organism excitation. In addition to these data, neuroscience studies have confirmed, as proposed by Freud, the homeostatic role of pleasure when the latter is triggered by an internal need. However, these studies have also indicated that, unlike proposed by Freud, pleasure is not only the result of obtaining a satisfaction but has also a role in the promotion of action. In sum, neuroscience suggest that the Freudian model favours the hedonic modality of reward circuit to the detriment of its motivational modality.

[From census to census: the occupational outlook for manual and nonmanual workers]. / De recensement en recensement, le devenir professionel des ouvriers et employes.

PIP: A logistic regression was conducted using data from France's Permanent Demographic Survey (EDP) to identify social and demographic factors involved in the passage of persons initially employed as laborers and lower level employees to higher status jobs, unemployment, or full-time housewife status. The EDP is a large scale longitudinal survey in which the same individuals are repeatedly interviewed. The surveys in 1968, 1975, 1982, and 1990 allowed three 7 or 8 year intercensal periods to be studied. The proportion of laborers and lower level employees who rose to higher status jobs increased from 9% during 1968-75 and 10% during 1975-82 to 14% during 1982-90. The trend to upward occupational mobility was directly related to rising educational levels. The risk of unemployment tripled over the course of the study. More than 1 woman in 5 left her job to become a housewife during 1968-75, but only 1 in 8 did so during 1982-90. Professional advancement in general is occurring at later ages. Cohorts born during World War II have advanced at younger ages than those born earlier or later. Women advanced to higher employment status 2 times less frequently than men, and their risk of unemployment was nearly double that of men. Their rate of advancement improved slightly over time, but their risk of unemployment did not. Individuals moving from one department to another had better chances of advancement.^ieng

[Sex and mortality in France, 1906-1980]. / Sexe et mortalite en France, 1906-1980.

PIP: Differential mortality in France is examined by sex, with a focus on the excess mortality among men during the period 1906-1980, using data from official and other published sources. The effects of occupation, social class, quality of medical care, and consumption of alchohol and tobacco are considered. The author finds that since 1976, life expectancy has been eight years higher for women than for men. While men employed in executive and white collar positions tend to live longer than their working-class counterparts, the situation is reversed for women, with executive women showing a higher mortality rate than other female employees and workers.^ieng