11,072 research outputs found
On the Hochschild-Kostant-Rosenberg map for graded manifolds
We show that the Hochschild-Kostant-Rosenberg map from the space of
multivector fields on a graded manifold N (endowed with a Berezinian volume) to
the cohomology of the algebra of multidifferential operators on N (as a
subalgebra of the Hochschild complex of the algebra of smooth functions on N)
is an isomorphism of Batalin-Vilkovisky algebras. These results generalize to
differential graded manifolds.Comment: 15 pages. Problematic Lemma 5.5 of v1 removed and Theorem 5.3b
corrected accordingly. Exposition reorganized. To appear in IMR
Environment induced incoherent controllability
We prove that the environment induced entanglement between two non
interacting, two-dimensional quantum systems S and P can be used to control the
dynamics of S by means of the initial state of P. Using a simple, exactly
solvable model, we show that both accessibility and controllability of S can be
achieved under suitable conditions on the interaction of S and P with the
environment.Comment: revtex4, 5 page
Decompositions of unitary evolutions and entanglement dynamics of bipartite quantum systems
We describe a decomposition of the Lie group of unitary evolutions for a
bipartite quantum system of arbitrary dimensions. The decomposition is based on
a recursive procedure which systematically uses the Cartan classification of
the symmetric spaces of the Lie group SO(n). The resulting factorization of
unitary evolutions clearly displays the local and entangling character of each
factor.Comment: 11 pages, revtex
BPS Wilson loops and Bremsstrahlung function in ABJ(M): a two loop analysis
We study a family of circular BPS Wilson loops in N=6 super
Chern-Simons-matter theories, generalizing the usual 1/2-BPS circle. The scalar
and fermionic couplings depend on two deformation parameters and these
operators can be considered as the ABJ(M) counterpart of the DGRT latitudes
defined in N=4 SYM. We perform a complete two-loop analysis of their vacuum
expectation value, discuss the framing dependence and propose a general
relation with cohomologically equivalent bosonic operators. We make an all-loop
proposal for computing the Bremsstrahlung function associated to the 1/2-BPS
cusp in terms of these generalized Wilson loops. When applied to our two-loop
result it reproduces the known expression. Finally, we comment on the
generalization of this proposal to the bosonic 1/6-BPS case.Comment: 46 pages, 6 figures; references adde
A matrix model for the latitude Wilson loop in ABJM theory
In ABJ(M) theory, we propose a matrix model for the exact evaluation of BPS
Wilson loops on a latitude circular contour, so providing a new weak-strong
interpolation tool. Intriguingly, the matrix model turns out to be a particular
case of that computing torus knot invariants in Chern-Simons
theory. At weak coupling we check our proposal against a three-loop
computation, performed for generic framing, winding number and representation.
The matrix model is amenable of a Fermi gas formulation, which we use to
systematically compute the strong coupling and genus expansions. For the
fermionic Wilson loop the leading planar behavior agrees with a previous string
theory prediction. For the bosonic operator our result provides a clue for
finding the corresponding string dual configuration. Our matrix model is
consistent with recent proposals for computing Bremsstrahlung functions exactly
in terms of latitude Wilson loops. As a by-product, we extend the conjecture
for the exact Bremsstrahlung function to generic
representations and test it with a four-loop perturbative computation. Finally,
we propose an exact prediction for at unequal gauge group ranks.Comment: 73 pages; v2: several improvements, JHEP published versio
Correlators of Hopf Wilson loops in the AdS/CFT correspondence
We study at quantum level correlators of supersymmetric Wilson loops with
contours lying on Hopf fibers of . In SYM theory the
strong coupling analysis can be performed using the AdS/CFT correspondence and
a connected classical string surface, linking two different fibers, is
presented. More precisely, the string solution describes oppositely oriented
fibers with the same scalar coupling and depends on an angular parameter,
interpolating between a non-BPS configuration and a BPS one. The system can be
thought as an alternative deformation of the ordinary antiparallel lines giving
the static quark-antiquark potential, that is indeed correctly reproduced, at
weak and strong coupling, as the fibers approach one another.Comment: 38 pages, 5 figure
Flow curvature effects on dynamic behaviour of a novel vertical axis tidal current turbine: numerical and experimental analysis
The paper deals with performances analysis of vertical axis turbine to exploit tidal marine currents. Flow curvature effects on performences of a novel vertical axis turbine have been investuigated. It has been shown that the flow curvature effect allows to design properly an accurate airfoil shape to increase turbine performances
Modeling the emergence of contact languages
Contact languages are born out of the non-trivial interaction of two (or more) parent languages.
Nowadays, the enhanced possibility of mobility and communication allows for a
strong mixing of languages and cultures, thus raising the issue of whether there are any
pure languages or cultures that are unaffected by contact with others. As with bacteria or viruses
in biological evolution, the evolution of languages is marked by horizontal transmission;
but to date no reliable quantitative tools to investigate these phenomena have been
available. An interesting and well documented example of contact language is the emergence
of creole languages, which originated in the contacts of European colonists and
slaves during the 17th and 18th centuries in exogenous plantation colonies of especially the
Atlantic and Indian Ocean. Here, we focus on the emergence of creole languages to demonstrate
a dynamical process that mimics the process of creole formation in American and
Caribbean plantation ecologies. Inspired by the Naming Game (NG), our modeling scheme
incorporates demographic information about the colonial population in the framework of a
non-trivial interaction network including three populations: Europeans, Mulattos/Creoles,
and Bozal slaves. We show how this sole information makes it possible to discriminate territories
that produced modern creoles from those that did not, with a surprising accuracy. The
generality of our approach provides valuable insights for further studies on the emergence
of languages in contact ecologies as well as to test specific hypotheses about the peopling
and the population structures of the relevant territories. We submit that these tools could be
relevant to addressing problems related to contact phenomena in many cultural domains:
e.g., emergence of dialects, language competition and hybridization,
globalization phenomena
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