A smooth entropy approach to quantum hypothesis testing and the classical capacity of quantum channels

We use the smooth entropy approach to treat the problems of binary quantum hypothesis testing and the transmission of classical information through a quantum channel. We provide lower and upper bounds on the optimal type II error of quantum hypothesis testing in terms of the smooth max-relative entropy of the two states representing the two hypotheses. Using then a relative entropy version of the Quantum Asymptotic Equipartition Property (QAEP), we can recover the strong converse rate of the i.i.d. hypothesis testing problem in the asymptotics. On the other hand, combining Stein's lemma with our bounds, we obtain a stronger (\ep-independent) version of the relative entropy-QAEP. Similarly, we provide bounds on the one-shot \ep-error classical capacity of a quantum channel in terms of a smooth max-relative entropy variant of its Holevo capacity. Using these bounds and the \ep-independent version of the relative entropy-QAEP, we can recover both the Holevo-Schumacher-Westmoreland theorem about the optimal direct rate of a memoryless quantum channel with product state encoding, as well as its strong converse counterpart.Comment: v4: Title changed, improved bounds, both direct and strong converse rates are covered, a new Discussion section added. 20 page

Discovery of Two Spectroscopically Peculiar, Low-Luminosity Quasars at z~4

We report the discovery of two low-luminosity quasars at z~4, both of which show prominent N IV] 1486A emission. This line is extremely rare in quasar spectra at any redshift; detecting it in two out of a sample of 23 objects (i.e., ~ 9% of the sample) is intriguing and is likely due to the low-luminosity, high-redshift quasar sample we are studying. This is still a poorly explored regime, where contributions from associated, early starbursts may be significant. One interpretation of this line posits photoionization by very massive young stars. Seeing N IV] 1486A emission in a high-redshift quasar may thus be understood in the context of co-formation and early co-evolution of galaxies and their supermassive black holes. Alternatively, we may be seeing a phenomenon related to the early evolution of quasar broad emission line regions. The non-detection (and possibly even broad absorption) of N V 1240A line in the spectrum of one of these quasars may support that interpretation. These two objects may signal a new faint quasar population or an early AGN evolutionary stage at high redshifts.Comment: 15 pages, 5 figures, Accepted for publicated in ApJ Letter

History dependence of directly observed magnetocaloric effects in (Mn, Fe)As

We use a calorimetric technique operating in sweeping magnetic field to study the thermomagnetic history- dependence of the magnetocaloric effect (MCE) in Mn0.985Fe0.015As. We study the magnetization history for which a "colossal" MCE has been reported when inferred indirectly via a Maxwell relation. We observe no colossal effect in the direct calorimetric measurement. We further examine the impact of mixed-phase state on the MCE and show that the first order contribution scales linearly with the phase fraction. This validates various phase-fraction based methods developed to remove the colossal peak anomaly from Maxwell-based estimates.Comment: 4 pages, 2 figure

Electrorheological Rayleigh-Taylor Instability at the Interface between a Porous Layer and Thin Shell with Poorly Conducting Couple Stress Fluid

This paper is concerned with the study of the Electrorheological Rayleigh-Taylor instability (ERTI) at the interface between a densely packed saturated poorly conducting couple stress porous layer accelerated by a lighter poorly conducting couple stress fluid in a thin shell in the presence of a transverse electric field and laser radiation. A simple theory based on fully developed flow approximations is used to derive the dispersion relation for the growth rate of ERTI. The cutoff and the maximum wave numbers and the corresponding maximum frequencies are obtained. It is shown that the effects of couple stress parameter and the electric field reduce the growth rate considerably compared to a non-conducting fluid in the absence of an electric field. These are favorable to control the surface instabilities in many practical applications discussed in this paper

The acetyl xylan esterase of Bacillus pumilus belongs to a family of esterases with broad substrate specificity

The Bacillus pumilus gene encoding acetyl xylan esterase tare) was identified and characterized. The axe gene was expressed and the recombinant enzyme produced in Escherichia coli was purified and characterized. The recombinant enzyme displayed similar properties to the acetyl xylan esterase (AXE) from B. pumilus. The AXE primary structure was 76% identical to the cephalosporin C deacetylase of B. subtilis, and 40% to two recently identified AXEs from Thermoanaerobacterium and Thermotoga maritima. These four proteins are of similar sire and represent a new family of esterases having a broad substrate specificity. The recombinant AXE was demonstrated to have activity on several acetylated substrates, including on cephalosporin C

Starvation Resistance is Associated with Developmentally Specified Changes in Sleep, Feeding and Metabolic Rate

Food shortage represents a primary challenge to survival, and animals have adapted diverse developmental, physiological and behavioral strategies to survive when food becomes unavailable. Starvation resistance is strongly influenced by ecological and evolutionary history, yet the genetic basis for the evolution of starvation resistance remains poorly understood. The fruit fly Drosophila melanogaster provides a powerful model for leveraging experimental evolution to investigate traits associated with starvation resistance. While control populations only live a few days without food, selection for starvation resistance results in populations that can survive weeks. We have previously shown that selection for starvation resistance results in increased sleep and reduced feeding in adult flies. Here, we investigate the ontogeny of starvation resistance-associated behavioral and metabolic phenotypes in these experimentally selected flies. We found that selection for starvation resistance resulted in delayed development and a reduction in metabolic rate in larvae that persisted into adulthood, suggesting that these traits may allow for the accumulation of energy stores and an increase in body size within these selected populations. In addition, we found that larval sleep was largely unaffected by starvation selection and that feeding increased during the late larval stages, suggesting that experimental evolution for starvation resistance produces developmentally specified changes in behavioral regulation. Together, these findings reveal a critical role for development in the evolution of starvation resistance and indicate that selection can selectively influence behavior during defined developmental time points