5,610 research outputs found
Distributed implementation of standard oracle operators
The standard oracle operator corresponding to a function f is a unitary
operator that computes this function coherently, i.e. it maintains
superpositions. This operator acts on a bipartite system, where the subsystems
are the input and output registers. In distributed quantum computation, these
subsystems may be spatially separated, in which case we will be interested in
its classical and entangling capacities. For an arbitrary function f, we show
that the unidirectional classical and entangling capacities of this operator
are log_{2}(n_{f}) bits/ebits, where n_{f} is the number of different values
this function can take. An optimal procedure for bidirectional classical
communication with a standard oracle operator corresponding to a permutation on
Z_{M} is given. The bidirectional classical capacity of such an operator is
found to be 2log_{2}(M) bits. The proofs of these capacities are facilitated by
an optimal distributed protocol for the implementation of an arbitrary standard
oracle operator.Comment: 4.4 pages, Revtex 4. Submitted to Physical Review Letter
On the existence of orthonormal geodesic bases for Lie algebras
We show that every unimodular Lie algebra, of dimension at most 4, equipped
with an inner product, possesses an orthonormal basis comprised of geodesic
elements. On the other hand, we give an example of a solvable unimodular Lie
algebra of dimension 5 that has no orthonormal geodesic basis, for any inner
product
Mental disorder as both natural and normative : developing the normative dimension of the 3e conceptual framework for psychopathology
Current arguments concerning the role of normativity within the concept of mental disorder are explored, and some requirements of a successful normative construal sketched out. We then shift to a discussion of "natural" normativity to lay the groundwork for our own understanding of what counts as a mental disorder. The view we present is grounded in an enactive, embodied, and embedded view of the mind (3e cognition). The position argued for is one where the labeling of a particular set of behaviors as disordered or dysfunctional is justified by the significant violation of norms, but where the norms in question are not socially imposed, rather they are the functional norms of the individual being diagnosed. The strengths and weaknesses of our position are discussed, and an addendum is proposed in response to a foreseeable counterargument. This construal provides a conceptual framework for thinking critically about normative issues in diagnosis, appreciates how central normativity is to the concept of mental disorder, and, finally (in being tied to the functionality of the individual), places the institutions of psychiatry and clinical psychology on good ethical ground and allows for consideration of cultural and individual variation during the diagnostic process
Experimental Quantum Process Discrimination
Discrimination between unknown processes chosen from a finite set is
experimentally shown to be possible even in the case of non-orthogonal
processes. We demonstrate unambiguous deterministic quantum process
discrimination (QPD) of non-orthogonal processes using properties of
entanglement, additional known unitaries, or higher dimensional systems. Single
qubit measurement and unitary processes and multipartite unitaries (where the
unitary acts non-separably across two distant locations) acting on photons are
discriminated with a confidence of in all cases.Comment: 4 pages, 3 figures, comments welcome. Revised version includes
multi-partite QP
Equilibration of quantum systems and subsystems
We unify two recent results concerning equilibration in quantum theory. We
first generalise a proof of Reimann [PRL 101,190403 (2008)], that the
expectation value of 'realistic' quantum observables will equilibrate under
very general conditions, and discuss its implications for the equilibration of
quantum systems. We then use this to re-derive an independent result of Linden
et. al. [PRE 79, 061103 (2009)], showing that small subsystems generically
evolve to an approximately static equilibrium state. Finally, we consider
subspaces in which all initial states effectively equilibrate to the same
state.Comment: 5 page
Unconditional security proof of long-distance continuous-variable quantum key distribution with discrete modulation
We present a continuous-variable quantum key distribution protocol combining
a discrete modulation and reverse reconciliation. This protocol is proven
unconditionally secure and allows the distribution of secret keys over long
distances, thanks to a reverse reconciliation scheme efficient at very low
signal-to-noise ratio.Comment: 4 pages, 2 figure
New Reports of Exotic and Native Ambrosia and Bark Beetle Species (Coleoptera: Curculionidae: Scolytinae) From Ohio
In a 2007 survey of ambrosia and bark beetles (Coleoptera: Curculionidae: Scolytinae) along a transect in northeastern Ohio, we collected six exotic and three native species not previously reported from the state. These species include the exotic ambrosia beetles Ambrosiodmus rubricollis (Eichhoff), Dryoxylon onoharaensum (Murayama), Euwallacea validus (Eichhoff), Xyleborus californicus Wood, Xyleborus pelliculosusEichhoff, and Xylosandrus crassiusculus (Motschulsky). The native ambrosia beetle Corthylus columbianus Hopkins, and the native bark beetles Dryocoetes autographus (Ratzeburg) and Hylastes tenuis Eichhoff are also reported from Ohio for the first time. Our study suggests a northward range expansion for five of the six exotic species including, X. crassiusculus, which is an important pest of nursery and orchard crops in the southeastern United States
The teacher education conversation: A network of cooperating teachers
This study investigated a professional learning community of cooperating teachers and university‐based teacher educators. To examine our roles and perspectives as colleagues in teacher education, we drew on frameworks in teacher learning and complexity science. Monthly group meetings of this inquiry community were held over two school years in a suburban school district in British Columbia. Participants’ current and prior experiences in the role of cooperating teacher provided rich topics for conversation. Our analysis illustrates how aspects of complexity thinking both enable and promote teacher learning, in this instance, the professional development of cooperating teachers. The study highlights (a) key tensions that allow for deeper exploration of issues, (b) the need for flexibility that is open to contingency, (c) the importance of reducing hierarchical structures to enable networks to develop, and (d) improvisation as a key ingredient for teacher learning
Production of Plant Sesquiterpenes in Saccharomyces cerevisiae:Effect of ERG9 Repression on Sesquiterpene Biosynthesis
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