31,434 research outputs found
The Power of LOCCq State Transformations
Reversible state transformations under entanglement non-increasing operations
give rise to entanglement measures. It is well known that asymptotic local
operations and classical communication (LOCC) are required to get a simple
operational measure of bipartite pure state entanglement. For bipartite mixed
states and multipartite pure states it is likely that a more powerful class of
operations will be needed. To this end \cite{BPRST01} have defined more
powerful versions of state transformations (or reducibilities), namely LOCCq
(asymptotic LOCC with a sublinear amount of quantum communication) and CLOCC
(asymptotic LOCC with catalysis). In this paper we show that {\em LOCCq state
transformations are only as powerful as asymptotic LOCC state transformations}
for multipartite pure states. We first generalize the concept of entanglement
gambling from two parties to multiple parties: any pure multipartite entangled
state can be transformed to an EPR pair shared by some pair of parties and that
any irreducible party pure state can be used to create any other
state (pure or mixed), using only local operations and classical communication
(LOCC). We then use this tool to prove the result. We mention some applications
of multipartite entanglement gambling to multipartite distillability and to
characterizations of multipartite minimal entanglement generating sets. Finally
we discuss generalizations of this result to mixed states by defining the class
of {\em cat distillable states}
Compression and R-wave detection of ECG/VCG data
Application of information theory to eliminate redundant part of electrocardiogram or vectorcardiogram is described. Operation of medical equipment to obtain three dimensional study of patient is discussed. Use of fast Fourier transform to accomplish data compression is explained
Entanglement molecules
We investigate the entanglement properties of multiparticle systems,
concentrating on the case where the entanglement is robust against disposal of
particles. Two qubits -belonging to a multipartite system- are entangled in
this sense iff their reduced density matrix is entangled. We introduce a family
of multiqubit states, for which one can choose for any pair of qubits
independently whether they should be entangled or not as well as the relative
strength of the entanglement, thus providing the possibility to construct all
kinds of ''Entanglement molecules''. For some particular configurations, we
also give the maximal amount of entanglement achievable.Comment: 4 pages, 1 figur
Activating bound entanglement in multi-particle systems
We analyze the existence of activable bound entangled states in
multi-particle systems. We first give a series of examples which illustrate
some different ways in which bound entangled states can be activated by letting
some of the parties to share maximally entangled states. Then, we derive
necessary conditions for a state to be distillable as well as to be activable.
These conditions turn out to be also sufficient for a certain family of
multi-qubit states. We use these results to explicitely to construct states
displaying novel properties related to bound entanglement and its activation.Comment: 8 pages, 3 figure
A BIO-ECONOMIC MODEL OF WETLAND PROTECTION ON PRIVATE LANDS
Wetland ecosystems on privately owned farms such as those on the Murrumbidgee River Floodplain in the state of New South Wales, Australia provide a mix of potentially valuable outputs to their owners and the wider community. The mix of values generated is dependent on the biophysical status of the wetlands, which in-turn, is dependent on the land management in and around these multiple-output ecosystems. Despite the range of private and public values generated, management decisions are based primarily on the private values that landowners receive. These private land management decisions also affect social values. Hence, there is potentially a demand for public policy to influence decisions based on the social values wetlands generate. This paper is predicated on the principle that good policy is reliant on information about wetland values. We present an integrated bio-economic model of wetland management that incorporates the biological and economic impacts at a landscape scale. The model reflects the multiple private and social values generated by wetlands and the dynamic nature of the trade-offs between these values. A number of broad policy conclusions for wetland management in Australia are generated from the outputs of the bio-economic model.Land Economics/Use,
Application of a transonic potential flow code to the static aeroelastic analysis of three-dimensional wings
Since the aerodynamic theory is nonlinear, the method requires the coupling of two iterative processes - an aerodynamic analysis and a structural analysis. A full potential analysis code, FLO22, is combined with a linear structural analysis to yield aerodynamic load distributions on and deflections of elastic wings. This method was used to analyze an aeroelastically-scaled wind tunnel model of a proposed executive-jet transport wing and an aeroelastic research wing. The results are compared with the corresponding rigid-wing analyses, and some effects of elasticity on the aerodynamic loading are noted
When only two thirds of the entanglement can be distilled
We provide an example of distillable bipartite mixed state such that, even in
the asymptotic limit, more pure-state entanglement is required to create it
than can be distilled from it. Thus, we show that the irreversibility in the
processes of formation and distillation of bipartite states, recently proved in
[G. Vidal, J.I. Cirac, Phys. Rev. Lett. 86, (2001) 5803-5806], is not limited
to bound-entangled states.Comment: 4 pages, revtex, 1 figur
Irreversibility in asymptotic manipulations of entanglement
We show that the process of entanglement distillation is irreversible by
showing that the entanglement cost of a bound entangled state is finite. Such
irreversibility remains even if extra pure entanglement is loaned to assist the
distillation process.Comment: RevTex, 3 pages, no figures Result on indistillability of PPT states
under pure entanglement catalytic LOCC adde
Half-Heusler semiconductors as piezoelectrics
One of the central challenges in materials science is the design of
functional and multifunctional materials, in which large responses are produced
by applied fields and stresses. A rapidly developing paradigm for the rational
design of such materials is based on the first-principles study of a large
materials family, the perovskite oxides being the prototypical case.
Specifically, first-principles calculations of structure and properties are
used to explore the microscopic origins of the functional properties of
interest and to search a large space of equilibrium and metastable phases to
identify promising candidate systems. In this paper, we use a first-principles
rational-design approach to demonstrate semiconducting half-Heusler compounds
as a previously-unrecognized class of piezoelectric materials, and to provide
guidance for the experimental realization and further investigation of
high-performance materials suitable for practical applications.Comment: 5 pages, 3 figues, 3 table
New classes of n-copy undistillable quantum states with negative partial transposition
The discovery of entangled quantum states from which one cannot distill pure
entanglement constitutes a fundamental recent advance in the field of quantum
information. Such bipartite bound-entangled (BE) quantum states \emph{could}
fall into two distinct categories: (1) Inseparable states with positive partial
transposition (PPT), and (2) States with negative partial transposition (NPT).
While the existence of PPT BE states has been confirmed, \emph{only one} class
of \emph{conjectured} NPT BE states has been discovered so far. We provide
explicit constructions of a variety of multi-copy undistillable NPT states, and
conjecture that they constitute families of NPT BE states. For example, we show
that for every pure state of Schmidt rank greater than or equal to three, one
can construct n-copy undistillable NPT states, for any . The abundance
of such conjectured NPT BE states, we believe, considerably strengthens the
notion that being NPT is only a necessary condition for a state to be
distillable.Comment: Latex, 10 page
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