Environment-Induced Decoherence and the Transition From Quantum to Classical

We study dynamics of quantum open systems, paying special attention to those aspects of their evolution which are relevant to the transition from quantum to classical. We begin with a discussion of the conditional dynamics of simple systems. The resulting models are straightforward but suffice to illustrate basic physical ideas behind quantum measurements and decoherence. To discuss decoherence and environment-induced superselection einselection in a more general setting, we sketch perturbative as well as exact derivations of several master equations valid for various systems. Using these equations we study einselection employing the general strategy of the predictability sieve. Assumptions that are usually made in the discussion of decoherence are critically reexamined along with the ``standard lore'' to which they lead. Restoration of quantum-classical correspondence in systems that are classically chaotic is discussed. The dynamical second law -it is shown- can be traced to the same phenomena that allow for the restoration of the correspondence principle in decohering chaotic systems (where it is otherwise lost on a very short time-scale). Quantum error correction is discussed as an example of an anti-decoherence strategy. Implications of decoherence and einselection for the interpretation of quantum theory are briefly pointed out.Comment: 80 pages, 7 figures included, Lectures given by both authors at the 72nd Les Houches Summer School on "Coherent Matter Waves", July-August 199

The evolution of language: a comparative review

For many years the evolution of language has been seen as a disreputable topic, mired in fanciful "just so stories" about language origins. However, in the last decade a new synthesis of modern linguistics, cognitive neuroscience and neo-Darwinian evolutionary theory has begun to make important contributions to our understanding of the biology and evolution of language. I review some of this recent progress, focusing on the value of the comparative method, which uses data from animal species to draw inferences about language evolution. Discussing speech first, I show how data concerning a wide variety of species, from monkeys to birds, can increase our understanding of the anatomical and neural mechanisms underlying human spoken language, and how bird and whale song provide insights into the ultimate evolutionary function of language. I discuss the ‘‘descended larynx’ ’ of humans, a peculiar adaptation for speech that has received much attention in the past, which despite earlier claims is not uniquely human. Then I will turn to the neural mechanisms underlying spoken language, pointing out the difficulties animals apparently experience in perceiving hierarchical structure in sounds, and stressing the importance of vocal imitation in the evolution of a spoken language. Turning to ultimate function, I suggest that communication among kin (especially between parents and offspring) played a crucial but neglected role in driving language evolution. Finally, I briefly discuss phylogeny, discussing hypotheses that offer plausible routes to human language from a non-linguistic chimp-like ancestor. I conclude that comparative data from living animals will be key to developing a richer, more interdisciplinary understanding of our most distinctively human trait: language

Children’s Interactions in an Asynchronous Video Mediated Communication Environment

Part 2: Long and Short PapersInternational audienceVideo-mediated communication (VMC) has become a feasible way to connect people in remote places for work and play. Nevertheless, little research has been done with regard to children and VMC. In this paper, we explore the behavior of a group of children, who exchanged video messages in an informal context. In particular, we have analyzed 386 videos over a period of 11 weeks, which were exchanged by 30 students of 4th and 5th grade from USA and Greece. We found that the number of views and the duration of a video message significantly depend on the gender of the viewer and creator. Most notably, girls created more messages, but boys viewed their own messages more. Finally, there are video messages with numerous views, which indicates that some videos have content qualities beyond the communication message itself. Overall, the practical implications of these findings indicate that the developers of asynchronous VMC should consider functionalities for preserving some of the video messages

Entangling the motion of diamonds at room temperature

2012 Conference on Lasers and Electro-Optics, CLEO 2012

Tentativa de infanticídio por um macho dominante de Alouatta caraya (Humboldt) (Primates, Atelidae) em um infante extra-grupo devido a influência do observador Infanticide attempt by a dominant male of Alouatta caraya (Humboldt) (Primates, Atelidae) against an extra-group infant due to the influence of the observer

Este trabalho relata um caso de tentativa de infanticídio por um macho residente e dominante de um grupo de Alouatta caraya (Humboldt, 1812) em um infante extra-grupo, em ilha do rio Paraná, Paraná, Brasil. O encontro do par fêmea-infante com o macho residente foi propiciado pela interferência humana. Devido às circunstâncias em que ocorreu o fato e a posição hierárquica do agressor, a hipótese de patologia social pareceu plausível na explicação do comportamento.<br>This work reports on an infanticide attempt by a dominant resident male in a group of Alouatta caraya (Humboldt, 1812) on an extra-group infant in an Island in the Paraná river, Paraná, Brazil. The encounter of an infant-female pair with a resident male was brought about by human interference. Give the circumstances in which the event ocurred and the hierarchical position of the agressor, the social pathology hypothesis seems the most plausible explanation for such behavior

Entangling the motion of diamonds at room temperature

Optics InfoBase Conference Paper

Entangling macroscopic diamonds at room temperature

10.1126/science.1211914Science33460601253-1256SCIE