3,367 research outputs found
Campus Art Museums in the 21st Century: A Conversation
In the summer of 2012, the authors of this study brought together a group of campus art museum directors and outside experts to 'think out loud' about the changes already occurring at campus museums and where new opportunities and roles may be emerging. We hope the resulting paper will further the field's larger, continuing exploration of its roles and potentials through dialogue, research, and experimentation -- an exploration that contributes to the continued healthy evolution of campus art museum practice
Resource theory of non-Gaussian operations
Non-Gaussian states and operations are crucial for various
continuous-variable quantum information processing tasks. To quantitatively
understand non-Gaussianity beyond states, we establish a resource theory for
non-Gaussian operations. In our framework, we consider Gaussian operations as
free operations, and non-Gaussian operations as resources. We define
entanglement-assisted non-Gaussianity generating power and show that it is a
monotone that is non-increasing under the set of free super-operations, i.e.,
concatenation and tensoring with Gaussian channels. For conditional unitary
maps, this monotone can be analytically calculated. As examples, we show that
the non-Gaussianity of ideal photon-number subtraction and photon-number
addition equal the non-Gaussianity of the single-photon Fock state. Based on
our non-Gaussianity monotone, we divide non-Gaussian operations into two
classes: (1) the finite non-Gaussianity class, e.g., photon-number subtraction,
photon-number addition and all Gaussian-dilatable non-Gaussian channels; and
(2) the diverging non-Gaussianity class, e.g., the binary phase-shift channel
and the Kerr nonlinearity. This classification also implies that not all
non-Gaussian channels are exactly Gaussian-dilatable. Our resource theory
enables a quantitative characterization and a first classification of
non-Gaussian operations, paving the way towards the full understanding of
non-Gaussianity.Comment: 15 pages, 4 figure
Improved sampling of the pareto-front in multiobjective genetic optimizations by steady-state evolution: a Pareto converging genetic algorithm
Previous work on multiobjective genetic algorithms has been focused on preventing genetic drift and the issue of convergence has been given little attention. In this paper, we present a simple steady-state strategy, Pareto Converging Genetic Algorithm (PCGA), which naturally samples the solution space and ensures population advancement towards the Pareto-front. PCGA eliminates the need for sharing/niching and thus minimizes heuristically chosen parameters and procedures. A systematic approach based on histograms of rank is introduced for assessing convergence to the Pareto-front, which, by definition, is unknown in most real search problems.
We argue that there is always a certain inheritance of genetic material belonging to a population, and there is unlikely to be any significant gain beyond some point; a stopping criterion where terminating the computation is suggested. For further encouraging diversity and competition, a nonmigrating island model may optionally be used; this approach is particularly suited to many difficult (real-world) problems, which have a tendency to get stuck at (unknown) local minima. Results on three benchmark problems are presented and compared with those of earlier approaches. PCGA is found to produce diverse sampling of the Pareto-front without niching and with significantly less computational effort
Gauge invariance of the background average effective action
Using the background field method for the functional renormalization group
approach in the case of a generic gauge theory, we study the background field
symmetry and gauge dependence of the background average effective action, when
the regulator action depends on external fields. The final result is that the
symmetry of the average effective action can be maintained for a wide class of
regulator functions, but in all cases the dependence of the gauge fixing
remains on-shell. The Yang-Mills theory is considered as the main particular
example.Comment: Fits the version accepted in EPJ
BSP-fields: An Exact Representation of Polygonal Objects by Differentiable Scalar Fields Based on Binary Space Partitioning
The problem considered in this work is to find a dimension independent algorithm for the generation of signed scalar fields exactly representing polygonal objects and satisfying the following requirements: the defining real function takes zero value exactly at the polygonal object boundary; no extra zero-value isosurfaces should be generated; C1 continuity of the function in the entire domain. The proposed algorithms are based on the binary space partitioning (BSP) of the object by the planes passing through the polygonal faces and are independent of the object genus, the number of disjoint components, and holes in the initial polygonal mesh. Several extensions to the basic algorithm are proposed to satisfy the selected optimization criteria. The generated BSP-fields allow for applying techniques of the function-based modeling to already existing legacy objects from CAD and computer animation areas, which is illustrated by several examples
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