The quantum brachistochrone problem for non-Hermitian Hamiltonians

Recently Bender, Brody, Jones and Meister found that in the quantum brachistochrone problem the passage time needed for the evolution of certain initial states into specified final states can be made arbitrarily small, when the time-evolution operator is taken to be non-Hermitian but PT-symmetric. Here we demonstrate that such phenomena can also be obtained for non-Hermitian Hamiltonians for which PT-symmetry is completely broken, i.e. dissipative systems. We observe that the effect of a tunable passage time can be achieved by projecting between orthogonal eigenstates by means of a time-evolution operator associated with a non-Hermitian Hamiltonian. It is not essential that this Hamiltonian is PT-symmetric

Calagem e gessagem para o tomateiro e o meloeiro irrigados no Semi-Árido nordestino.

Instalou-se um experimento no Submédio São Francisco com o objetivo de avaliar o efeito da calagem e gessagem na produtividade e qualidade do tomate e melão. O delineamento foi em blocos ao acaso, com quatro repetições e sete tratamentos: 1) testemunha; 2) 0,5 vezes a necessidade de calagem (N.C.) na forma de calcário (0,5 x N.C. -Ca); 3) 1 x N.C. - Ca; 4) 2 x N.C. -Ca; 5) 0,5 x N.C., na forma de 2/3 de calcário e 1/3 de gesso (0,5 x N.C. - CaGe); 6) 1 x N.C -CaGe ; 7) 2 x N.C. -CaGe. Não se verificou efeitos significativos sobre a produtividade do tomate e a qualidade do melão. Com aplicação de 2 t/ha de calcário (1 x N.C -Ca) obteve-se uma produtividade de melão de 22,52 t/ha, significativamente superior à da testemunha, 16,77 t/ha, e reduziu-se a podridão apical do tomate em 80,4% em relação à da testemunha.Suplemento 2

Vacuumless kinks systems from vacuum ones, an example

Some years ago, Cho and Vilenkin, introduced a model which presents topological solutions, despite not having degenerate vacua as is usually expected. Here we present a new model with topological defects, connecting degenerate vacua but which in a certain limit recovers precisely the one proposed originally by Cho and Vilenkin. In other words, we found a kind of parent model for the so called vacuumless model. Then the idea is extended to a model recently introduced by Bazeia et al. Finally, we trace some comments the case of the Liouville model.Comment: 11 pages, 4 figure

Estirpes de bactérias selecionadas para a otimização da fixação biológica de nitrogênio em leguminosas florestais .

Este comunicado apresenta resultados de pesquisas referente a seleção de estirpes em condições estéreis para Chamaecrista nictitans (L.) Moench, Mimosa pellita L. e Mimosa floculosa Burkart (etapa 2) e em condições não estéreis para Mimosa xantocentra Mart. e Erythrina falcata Benth (etapa 3). As estirpes testadas pertencem a coleção do Laboratório de Leguminosas da Embrapa Agrobiologia.bitstream/item/42764/1/COT120-09.pd

Cultivos da cebola e do tomate industrial.

Manejo da cultura. Recomendacoes tecnicas e coeficientes tecnico para o plantio.bitstream/item/137803/1/ID-7006.pdfApostila do Curso de Atualizacao Tecnica para Engenheiros Agronomos do Banco do Brasil, Petrolina, 1995

Food consumption of Rhammatocerus schistocercoides Rehn (Orthoptera: Acrididae) infected by the fungus Metarhizium flavoviride Gams & Rozsypal.

Made available in DSpace on 2018-06-11T19:01:59Z (GMT). No. of bitstreams: 1 ID25630.pdf: 802298 bytes, checksum: c6ff3635c18289c1e47d0d8817abacb4 (MD5) Previous issue date: 2005-09-26bitstream/item/178447/1/ID-25630.pd

Quantum bridges in phase space: Interference and nonclassicality in strong-field enhanced ionisation

We perform a phase-space analysis of strong-field enhanced ionisation in molecules, with emphasis on quantum-interference effects. Using Wigner quasi-probability distributions and the quantum Liouville equation, we show that the momentum gates reported in a previous publication [N. Takemoto and A. Becker, Phys. Rev. A \textbf{84}, 023401 (2011)] may occur for static driving fields, and even for no external field at all. Their primary cause is an interference-induced bridging mechanism that occurs if both wells in the molecule are populated. In the phase-space regions for which quantum bridges occur, the Wigner functions perform a clockwise rotation whose period is intrinsic to the molecule. This evolution is essentially non-classical and non-adiabatic, as it does not follow equienergy curves or field gradients. Quasi-probability transfer via quantum bridges is favoured if the electron's initial state is either spatially delocalised, or situated at the upfield molecular well. Enhanced ionisation results from the interplay of this cyclic motion, adiabatic tunnel ionisation and population trapping. Optimal conditions require minimising population trapping and using the bridging mechanism to feed into ionisation pathways along the field gradient.Comment: 27 pages, 13 figures; some figures have been simplified to comply with the arXiv requirement