Entangling power of quantized chaotic systems

We study the quantum entanglement caused by unitary operators that have classical limits that can range from the near integrable to the completely chaotic. Entanglement in the eigenstates and time-evolving arbitrary states is studied through the von Neumann entropy of the reduced density matrices. We demonstrate that classical chaos can lead to substantially enhanced entanglement. Conversely, entanglement provides a novel and useful characterization of quantum states in higher dimensional chaotic or complex systems. Information about eigenfunction localization is stored in a graded manner in the Schmidt vectors, and the principal Schmidt vectors can be scarred by the projections of classical periodic orbits onto subspaces. The eigenvalues of the reduced density matrices are sensitive to the degree of wavefunction localization, and are roughly exponentially arranged. We also point out the analogy with decoherence, as reduced density matrices corresponding to subsystems of fully chaotic systems are diagonally dominant.Comment: 21 pages including 9 figs. (revtex

Avaliação de programas hormonais para a indução e sincronização do estro em caprinos Evaluation of hormonal programs to induce and synchronize estrus in goats

O objetivo deste trabalho foi estabelecer alternativas para indução e sincronização do estro em cabras leiteiras manejadas semi-intensivamente. Foram conduzidos quatro experimentos com 411 cabras na Embrapa-Centro Nacional de Pesquisa deCaprinos, Sobral, CE. No protocolo básico, utilizaram-se esponjas intra-vaginais com 50 mg de acetato de medroxiprogesterona (MAP) por dez dias e aplicação intra-muscular de 100 mig de cloprostenol e 200 UI de gonadotropina coriônica eqüina (eCG) no 8º dia; a inseminação artificial (IA), com sêmen congelado foi feita 38 horas após remoção da esponja. No experimento1 substituiu-se a e CG pelo "efeito macho"; no experimento 2 substituiu-se a dose de MAP para 60 mg; no experimento3 compararam-se diferentes momentos de IA: 38, 44 e 50 horas e no experimento 4 substituiu-se a eCG pela gonadotropina humana (hCG). Nenhuma das alternativas testadas modificou (P>0,05) a prolificidade. A IA em cio natural gerou maior (P<0,05) índice de parição no experimento2(67,7%) e no experimento 4 (73,3%). A dose de 60 mg de MAP permitiu realizar a IA mais tarde (44 horas apósretirar a esponja) sem detrimento da fertilidade. A hCG equivaleu a eCG, se aplicada 48 horas antes de retirar a esponja.<br>The objective of this study was to establish alternatives to induce and synchronize estrus in dairy goats managed under semi-intensive conditions. Four experiments were carried out using 411 goats at the Embrapa-Centro Nacional de Pesquisa de Caprinos, Sobral, CE, Brazil. In the basic protocol, intra-vaginal sponges were used with 50 mg of medroxyprogesterone acetate (MAP) over ten days, associated with intra-muscular shots of cloprostenol, and equine corionic gonadotropin (eCG) at the 8th day. Artificial insemination (AI) with frozen semen took place 38 hours after sponge withdrawal. In the first experiment, eCG was replaced by "buck effect"; in the second experiment, 60 mg MAP replaced the usual dose; the third experiment compared different pre-fixed time for AI: 38, 44 and 50 hours and in the fourth experiment, hCG (human corionic gonadotropin) given at different moments, replaced eCG. Prolificacy was not influenced (P>0.05) by any changes of basic protocol.After natural estrus, AIprovided higher (P<0.05) parturition rates in the second (67.7%) and fourth experiment (73.3%). Sponge with 60mg MAP allowed to inseminate later (44 hours after removal) without impairing fertility. As long as hCG is given 48 hours before sponge removal it results equals to eCG ones