Positivity in the presence of initial system-environment correlation

The constraints imposed by the initial system-environment correlation can lead to nonpositive Dynamical maps. We find the conditions for positivity and complete positivity of such dynamical maps by using the concept of an assignment map. Any initial system-environment correlations make the assignment map nonpositive, while the positivity of the dynamical map depends on the interplay between the assignment map and the system-environment coupling. We show how this interplay can reveal or hide the nonpositivity of the assignment map. We discuss the role of this interplay in Markovian models.Comment: close to the published version. 5 pages, 1 figur

Proof-Pattern Recognition and Lemma Discovery in ACL2

We present a novel technique for combining statistical machine learning for proof-pattern recognition with symbolic methods for lemma discovery. The resulting tool, ACL2(ml), gathers proof statistics and uses statistical pattern-recognition to pre-processes data from libraries, and then suggests auxiliary lemmas in new proofs by analogy with already seen examples. This paper presents the implementation of ACL2(ml) alongside theoretical descriptions of the proof-pattern recognition and lemma discovery methods involved in it

Bogoliubov space of a Bose--Einstein condensate and quantum spacetime fluctuations

In the present work we consider the role that metric fluctuations could have upon the properties of a Bose--Einstein condensate. In particular we consider the Bogoliubov space associated to it and show that there are, at least, two independent ways in which the average size of these metric fluctuations could be, experimentally, determined. Indeed, we prove that the pressure and the speed of sound of the ground state define an expression allowing us to determine the average size of these fluctuations. Afterwards, an interferometric experiment involving Bogoliubov excitations of the condensate and the pressure (or the speed of sound of the ground state) provides a second and independent way in which this average size could be determined, experimentally

Evidence for magnetic clusters in BaCoO3_3

Magnetic properties of the transition metal oxide BaCoO$_3$ are analyzed on the basis of the experimental and theoretical literature available via ab inito calculations. These can be explained by assuming the material to be formed by noninteracting ferromagnetic clusters of about 1.2 nm in diameter separated by about 3 diameters. Above about 50 K, the so-called blocking temperature, superparamagnetic behavior of the magnetic clusters occurs and, above 250 K, paramagnetism sets in.Comment: 4 pages, 1 figur

Characterization of quantum angular-momentum fluctuations via principal components

We elaborate an approach to quantum fluctuations of angular momentum based on the diagonalization of the covariance matrix in two versions: real symmetric and complex Hermitian. At difference with previous approaches this is SU(2) invariant and avoids any difficulty caused by nontrivial commutators. Meaningful uncertainty relations are derived which are nontrivial even for vanishing mean angular momentum. We apply this approach to some relevant states.Comment: 10 pages, Two column. New section II and some clarifying comment

Morbidity and mortality in reptiles presented to a wildlife care facility in Central Illinois

We examined morbidity and mortality of 200 reptiles, representing 13 different species that were presented to the University of Illinois Wildlife Medical Clinic (WMC) from 2003 to 2010. Snapping turtles (Chelydra serpentine; n = 46), box turtles (Terrapene sp.; n = 43), painted turtles (Chrysemys picta; n = 37), and red-eared slider turtles (Trachemys scripta elegans; n = 33) were the most frequently seen species. Turtles were significantly more likely to be presented to the WMC following collision with a motor vehicle (n = 73) than any other reason, including idiopathic trauma (i.e., trauma of unknown origin; n = 25) or infectious disease (n =18). The findings from this cross-sectional study suggest a potential for community education in limiting reptile traumas resulting in presentations to a wildlife hospital

Drawing the Line: How African, Caribbean and White British Women Live Out Psychologically Abusive Experiences

The final, definitive version of this paper has been published in Violence Against Women, 19 (9):1104-32, Sept 2013 by SAGE Publications Ltd, All rights reserved. © The Author(s) 2013. The online version of this article can be found at: http://vaw.sagepub.com/content/19/9/110

Extended Dualization: a method for the Bosonization of Anomalous Fermion Systems in Arbitrary Dimension

The technique of extended dualization developed in this paper is used to bosonize quantized fermion systems in arbitrary dimension $D$ in the low energy regime. In its original (minimal) form, dualization is restricted to models wherein it is possible to define a dynamical quantized conserved charge. We generalize the usual dualization prescription to include systems with dynamical non--conserved quantum currents. Bosonization based on this extended dualization requires the introduction of an additional rank $0$ (scalar) field together with the usual antisymmetric tensor field of rank $(D-2)$. Our generalized dualization prescription permits one to clearly distinguish the arbitrariness in the bosonization from the arbitrariness in the quantization of the system. We study the bosonization of four--fermion interactions with large mass in arbitrary dimension. First, we observe that dualization permits one to formally bosonize these models by invoking the bosonization of the free massive Dirac fermion and adding some extra model--dependent bosonic terms. Secondly, we explore the potential of extended dualization by considering the particular case of \underbar{chiral} four--fermion interactions. Here minimal dualization is inadequate for calculating the extra bosonic terms. We demonstrate the utility of extended dualization by successfully completing the bosonization of this chiral model. Finally, we consider two examples in two dimensions which illuminate the utility of using extended dualization by showing how quantization ambiguities in a fermionic theory propagate into the bosonized version. An explicit parametrization of the quantization ambiguities of the chiral current in the Chiral Schwinger model is obtained. Similarly, for the sine--Gordon interaction in the massive Thirring model the quantizationComment: Revised version including major changes in section 3, to be published in Phys. Rev.