Multi-Party Pseudo-Telepathy

Quantum entanglement, perhaps the most non-classical manifestation of quantum information theory, cannot be used to transmit information between remote parties. Yet, it can be used to reduce the amount of communication required to process a variety of distributed computational tasks. We speak of pseudo-telepathy when quantum entanglement serves to eliminate the classical need to communicate. In earlier examples of pseudo-telepathy, classical protocols could succeed with high probability unless the inputs were very large. Here we present a simple multi-party distributed problem for which the inputs and outputs consist of a single bit per player, and we present a perfect quantum protocol for it. We prove that no classical protocol can succeed with a probability that differs from 1/2 by more than a fraction that is exponentially small in the number of players. This could be used to circumvent the detection loophole in experimental tests of nonlocality.Comment: 11 pages. To be appear in WADS 2003 proceeding

Spectroscopy of ultrathin epitaxial rutile TiO[sub 2](110) films grown on W(100)

Epitaxial ultrathin titanium dioxide films of 0.3 to similar to 7 nm thickness on a metal single crystal substrate have been investigated by high resolution vibrational and electron spectroscopies. The data complement previous morphological data provided by scanned probe microscopy and low energy electron diffraction to provide very complete characterization of this system. The thicker films display electronic structure consistent with a stoichiometric TiO2 phase. The thinner films appear nonstoichiometric due to band bending and charge transfer from the metal substrate, while work function measurements also show a marked thickness dependence. The vibrational spectroscopy shows three clear phonon bands at 368, 438, and 829 cm(-1) (at 273 K), which confirms a rutile structure. The phonon band intensity scales linearly with film thickness and shift slightly to lower frequencies with increasing temperature, in accord with results for single crystals. (c) 2007 American Institute of Physics

Promoting women's health in Texas: suggestions for maximizing the benefits of the Women's Health Program

This thesis presents a collection of recommendations on how to increase participation in a Texas Medicaid family planning program, called the Texas Women’s Health Program, or WHP. Based on findings discovered during a series of thirteen elite interviews, these suggestions range from communications strategies, such as preferred media channels, to general policy and program implementation recommendations. A review of marketing and health communication literature was also employed as a means of supporting and complementing interview findings. Set in the bitter family planning climate of a Bible-belt state, this study provides an in-depth look at how public health policies and outreach efforts can be improved by taking a marketing approach.Advertisin

Largest separable balls around the maximally mixed bipartite quantum state

For finite-dimensional bipartite quantum systems, we find the exact size of the largest balls, in spectral $l_p$ norms for $1 \le p \le \infty$, of separable (unentangled) matrices around the identity matrix. This implies a simple and intutively meaningful geometrical sufficient condition for separability of bipartite density matrices: that their purity \tr \rho^2 not be too large. Theoretical and experimental applications of these results include algorithmic problems such as computing whether or not a state is entangled, and practical ones such as obtaining information about the existence or nature of entanglement in states reached by NMR quantum computation implementations or other experimental situations.Comment: 7 pages, LaTeX. Motivation and verbal description of results and their implications expanded and improved; one more proof included. This version differs from the PRA version by the omission of some erroneous sentences outside the theorems and proofs, which will be noted in an erratum notice in PRA (and by minor notational differences

The Leucocytozoidae of South African birds. The Muscicapidae sensu latu

The leucocytozoids of the Muscicapidae sensu latu are reviewed and Leucocytozoon phylbscopus of the Sylviinae, L. liothricis of the Timaliinae, L. dubreuili, L. mcclurei and L. shaartusicum of the Turdinae are redescribed. Leucocytozoon francai, L. gbvannolia and L. mirandae are declared synonyms of L. dubreuili. Leucocytozoon timaliae n. sp. is described from a South African babbler

The haemoproteids of the shrikes of the avian family Laniidae (Passeriformes)

The two haemoproteids parasitizing members of the avian family Laniidae are reviewed. Haemoproteus lanii de Mello, 1937 is re-described and a neohapantotype designated; H. lanii var. nucleophilus Helmy Mohammed, 1958 is considered to be the same as H. lanii and therefore the varietal (= subspecific) designation is suppressed; it is confirmed that H. lanuidae Yakunin, 1976 is declared a nomen nudum; Haemoproteus cublae Peirce, 1984 is re-described

Supercatalysis

We show that entanglement-assisted transformations of bipartite entangled states can be more efficient than catalysis [D. Jonathan and M. B. Plenio, Phys. Rev. Lett. 83, 3566 (1999)}, i.e., given two incomparable bipartite states not only can the transformation be enabled by performing collective operations with an auxiliary entangled state, but the entanglement of the auxiliary state itself can be enhanced. We refer to this phenomenon as supercatalysis. We provide results on the properties of supercatalysis and its relationship with catalysis. In particular, we obtain a useful necessary and sufficient condition for catalysis, provide several sufficient conditions for supercatalysis and study the extent to which entanglement of the auxiliary state can be enhanced via supercatalysis.Comment: Latex, 5 page

Local transformation of mixed states of two qubits to Bell diagonal states

The optimal entanglement manipulation for a single copy of mixed states of two qubits is to transform it to a Bell diagonal state. In this paper we derive an explicit form of the local operation that can realize such a transformation. The result obtained is universal for arbitrary entangled two-qubit states and it discloses that the corresponding local filter is not unique for density matrices with rank $n=2$ and can be exclusively determined for that with $n=3$ and 4. As illustrations, a four-parameters family of mixed states are explored, the local filter as well as the transformation probability are given explicitly, which verify the validity of the general result.Comment: 5 pages, to be published in Phys. Rev.

The Leucocytozoidae of South African birds. The Coliiformes and Coraciiformes

The leucocytozoids of the avian orders Coliiformes and Coraciiformes are reviewed. Leucocytozoon colius of the Coliidae, L. alcedinis and L. dacelo of the Alcedinidae and L. bucerotis of the Bucerotidae are described as new species. Leucocytozoon eurystomi, L. nyctyornis and L. communis of the Coraciidae, Meropidae and Upupidae respectively are redescribed. Leucocytozoon coraciae, L. francae, L. leitaoi and L. melloi are declared synonyms of L. eurystomi. Leucocytozoon apiaster of the Meropidae and L. musajevi of the Coraciidae have previously been declared nomina nuda

Perfect state distinguishability and computational speedups with postselected closed timelike curves

Bennett and Schumacher's postselected quantum teleportation is a model of closed timelike curves (CTCs) that leads to results physically different from Deutsch's model. We show that even a single qubit passing through a postselected CTC (P-CTC) is sufficient to do any postselected quantum measurement, and we discuss an important difference between "Deutschian" CTCs (D-CTCs) and P-CTCs in which the future existence of a P-CTC might affect the present outcome of an experiment. Then, based on a suggestion of Bennett and Smith, we explicitly show how a party assisted by P-CTCs can distinguish a set of linearly independent quantum states, and we prove that it is not possible for such a party to distinguish a set of linearly dependent states. The power of P-CTCs is thus weaker than that of D-CTCs because the Holevo bound still applies to circuits using them regardless of their ability to conspire in violating the uncertainty principle. We then discuss how different notions of a quantum mixture that are indistinguishable in linear quantum mechanics lead to dramatically differing conclusions in a nonlinear quantum mechanics involving P-CTCs. Finally, we give explicit circuit constructions that can efficiently factor integers, efficiently solve any decision problem in the intersection of NP and coNP, and probabilistically solve any decision problem in NP. These circuits accomplish these tasks with just one qubit traveling back in time, and they exploit the ability of postselected closed timelike curves to create grandfather paradoxes for invalid answers.Comment: 15 pages, 4 figures; Foundations of Physics (2011