55 research outputs found
Holographic entanglement as nonlocal magnetism
The Ryu-Takayanagi prescription can be cast in terms of a set of microscopic
threads that help visualize holographic entanglement in terms of distillation
of EPR pairs. While this framework has been exploited for regions with a high
degree of symmetry, we take the first steps towards understanding general
entangling regions, focusing on AdS. Inspired by simple constructions
achieved for the case of disks and the half-plane, we reformulate bit threads
in terms of a magnetic-like field generated by a current flowing through the
boundary of the entangling region. The construction is possible for these
highly symmetric settings, leading us to a modified Biot-Savart law in curved
space that fully characterizes the entanglement structure of the state. For
general entangling regions, the prescription breaks down as the corresponding
modular Hamiltonians become inherently nonlocal. We develop a formalism for
general shape deformations and derive a flow equation that accounts for these
effects as a systematic expansion. We solve this equation for a complete set of
small deformations and show that the structure of the expansion explicitly
codifies the expected nonlocalities. Our findings are consistent with numerical
results existing in the literature, and shed light on the fundamental nature of
quantum entanglement as a nonlocal phenomenon.Comment: 28 pages, 5 figure
Bath-induced correlations lead to sub-shot-noise thermometry precision
We study the role of bath-induced correlations in temperature estimation of
cold Bosonic baths. Our protocol includes multiple probes, that are not
interacting, nor are they initially correlated to each other. They interact
with a Bosonic sample and reach a non-equilibrium steady state, which is
measured to estimate the temperature of the sample. It is well-known that in
the steady state such non-interacting probes may get correlated to each other
and even entangled. Nonetheless, the impact of these correlations in metrology
has not been deeply investigated yet. Here, we examine their role for
thermometry of cold Bosonic gases and show that, although being classical,
bath-induced correlations can indeed lead to sub-shot-noise precision for
thermometry at low temperatures; e.g., for a probe of non-interacting
impurities they can enhance the quantum Fisher information by two orders of
magnitude. The proposed thermometry scheme here does not require precise
dynamical control of the probes and tuning the parameters, as it is build upon
the non-equilibrium steady state of a non-interacting system. Our results put
forward new possibilities in thermometry at low temperatures, of relevance for
instance in cold gases and Bose--Einstein condensates.Comment: Comments are welcome
Desempenho de cordeiros Santa Inês alimentados com diferentes níveis de feno de erva-sal (Atriplex nummularia L.).
O objetivo deste trabalho foi avaliar o desempenho de cordeiros Santa Inês alimentados com diferentes níveis de feno de erva-sal (Atriplex nummularia L.) em confinamento
Avaliação do pH, temperatura, sal e condutividade no líquido ruminal de ovinos recebendo dietas a base de palma forrageira e feno de atriplex.
Este trabalho teve por objetivo avaliar os efeitos da substituição da palma forrageira (Opuntia ficus indica,Mill) por feno de atriplex (Atriplex nummularia Lind.) sobre o pH, temperatura, concentração de sal e condutividade do líquido ruminal de ovinos. Os níveis de substituição da palma pelo feno foram de 0; 12,5; 25; 37,5 e 50 %. Foram utilizados cinco carneiros adultos, com fístula permanente no rúmen, com peso vivo médio de 60 kg. Os animais foram alojados em baias individuais, distribuídos no delineamento quadrado latino 5 x 5 (cinco animais x cinco dietas e cinco períodos experimentais), cada período foi constituído de 17 dias, sendo os quatros últimos reservados para as coletas de líquido ruminal. As amostras foram tomadas as 0 e 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, e 11 horas após alimentação dos animais. A concentração de amônia ruminal (N-NH3) apresentou efeito significativo (P<0,05) com aumento do feno de atriplex nas dietas, com valores de 10,26 e 39,29 mg/100mL para os respectivos níveis de feno 0 e 50 %. Quanto aos valores de pH, temperatura, concentração de sal e condutividade não tiveram efeito significativo com o aumento dos níveis de feno de atriplex. A substituição da palma por feno de atriplex promoveu efeito sobre a concentração ruminal de amôni
Comportamento ingestivo de ovinos recebendo dieta à base de palma forrageira e feno de atriplex.
O trabalho teve por objetivo avaliar o comportamento ingestivo de ovinos recebendo dieta à base de palma forrageira (73;54,8; 36,5; 8,3e 0,0%), feno de atriplex (0;12,5; 25,0; 37,5e 50,0%), e concentrado (farelo de soja, farelo de milho e uréia) em diferentes proporções na dieta. Foram utilizados cinco ovinos, fistulados no rúmen, com peso médio de 60 kg, alojados em baias individuais, distribuídos no delineamento quadrado latino 5 X 5 (5 animais X 5 dietas X 5 períodos). As observações comportamentais foram realizadas no sétimo dia de adaptação a dieta experimental em intervalos de cinco minutos durante24h. Verificou-se diferença significativa (p0,05) entre as dietas,com o valores de108, 133, 151, 150e 132minutos para os níveis de 0;12,5; 25,0; 37,5e 50,0% de feno de atriplex
Adaptability and Stability of Productive Characteristics on the Selection of Pennisetum purpureum Schum. Clones Grazed by Sheep
Elephant grass (Pennisetum purpureum Schum.) is one of the most widely used forages in Brazil, due to its high potential productivity, forage quality, palatability, vigour and persistence. Dwarf types of elephant grass are the object of selection programs for their higher leaf/stem ratio and lower grazing height, resulting in more efficient pasture management. They have high potential for ruminant production (Almeida et al. 2000), but have markedly different morphological and productive characteristics (Cunha et al. 2011) to tall varieties of the same species.
Adaptability and stability analyses are selection tools which allow identification of plant responses to different environments (Cruz and Regazzi 2001) and can identify stable productive clones across a range of environments. This study evaluated the genotype x environment interaction for productive characteristics of P. purpureum clones grazed by sheep
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