Subsurface processes generated by bore-driven swash on coarse-grained beaches

Peer reviewedPublisher PD

Entanglement in spin chains and lattices with long-range Ising-type interactions

We consider N initially disentangled spins, embedded in a ring or d-dimensional lattice of arbitrary geometry, which interact via some long--range Ising--type interaction. We investigate relations between entanglement properties of the resulting states and the distance dependence of the interaction in the limit N to infinity. We provide a sufficient condition when bipartite entanglement between blocks of L neighboring spins and the remaining system saturates, and determine S_L analytically for special configurations. We find an unbounded increase of S_L as well as diverging correlation and entanglement length under certain circumstances. For arbitrarily large N, we can efficiently calculate all quantities associated with reduced density operators of up to ten particles.Comment: 4 pages, 2 figures; V2: presentation improved, references adde

Observation of a Cs-induced state in the band gap of GaP(110): Alkali-metal bonding and Fermi-level pinning

The deposition of submonolayer quantities of Cs onto GaP(110) causes strong photoemission features in the region of the semiconductor fundamental band gap. This observation is interpreted in terms of emission from a hybrid state caused by the interaction of the Cs 6s level with the unoccupied dangling-bond state. This hybrid state has long been postulated in descriptions of the metal-semiconductor surface bond, and is responsible for the pinning of the Fermi level. The absence of dispersion in the state suggests that Cs/GaP(110) represents a realization of a Mott-Hubbard insulator, by comparison with results from other alkali-metal/compound-semiconductor systems

Singular value decomposition and matrix reorderings in quantum information theory

We review Schmidt and Kraus decompositions in the form of singular value decomposition using operations of reshaping, vectorization and reshuffling. We use the introduced notation to analyse the correspondence between quantum states and operations with the help of Jamiolkowski isomorphism. The presented matrix reorderings allow us to obtain simple formulae for the composition of quantum channels and partial operations used in quantum information theory. To provide examples of the discussed operations we utilize a package for the Mathematica computing system implementing basic functions used in the calculations related to quantum information theory.Comment: 11 pages, no figures, see http://zksi.iitis.pl/wiki/projects:mathematica-qi for related softwar

More efficient Bell inequalities for Werner states

In this paper we study the nonlocal properties of two-qubit Werner states parameterized by the visibility parameter 0<p<1. New family of Bell inequalities are constructed which prove the two-qubit Werner states to be nonlocal for the parameter range 0.7056<p<1. This is slightly wider than the range 0.7071<p<1, corresponding to the violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality. This answers a question posed by Gisin in the positive, i.e., there exist Bell inequalities which are more efficient than the CHSH inequality in the sense that they are violated by a wider range of two-qubit Werner states.Comment: 7 pages, 1 figur

Massive and Massless Neutrinos on Unbalanced Seesaws

The observation of neutrino oscillations requires new physics beyond the standard model (SM). A SM-like gauge theory with p lepton families can be extended by introducing q heavy right-handed Majorana neutrinos but preserving its SU(2)_L x U(1)_Y gauge symmetry. The overall neutrino mass matrix M turns out to be a symmetric (p+q) x (p+q) matrix. Given p>q, the rank of M is in general equal to 2q, corresponding to 2q non-zero mass eigenvalues. The existence of (p-q) massless left-handed Majorana neutrinos is an exact consequence of the model, independent of the usual approximation made in deriving the Type-I seesaw relation between the effective p x p light Majorana neutrino mass matrix M_\nu and the q x q heavy Majorana neutrino mass matrix M_R. In other words, the numbers of massive left- and right-handed neutrinos are fairly matched. A good example to illustrate this seesaw fair play rule is the minimal seesaw model with p=3 and q=2, in which one massless neutrino sits on the unbalanced seesaw.Comment: RevTex 8 pages, 1 PS figure. Two crucial references adde

Common genomic features of Campylobacter jejuni subsp. doylei strains distinguish them from C. jejuni subsp. jejuni

<p>Abstract</p> <p>Background</p> <p><it>Campylobacter jejuni </it>has been divided into two subspecies: <it>C. jejuni </it>subsp. <it>jejuni </it>(<it>Cjj</it>) and <it>C. jejuni </it>subsp. <it>doylei </it>(<it>Cjd</it>). Nearly all of the <it>C. jejuni </it>strains isolated are <it>Cjj</it>; nevertheless, although <it>Cjd </it>strains are isolated infrequently, they differ from <it>Cjj </it>in two key aspects: they are obtained primarily from human clinical samples and are associated often with bacteremia, in addition to gastroenteritis. In this study, we utilized multilocus sequence typing (MLST) and a DNA microarray-based comparative genomic indexing (CGI) approach to examine the genomic diversity and gene content of <it>Cjd </it>strains.</p> <p>Results</p> <p>A geographically diverse collection of eight <it>Cjd </it>strains was examined by MLST and determined to be phylogenetically distinct from <it>Cjj </it>strains. Microarray-based CGI approach also supported this. We were able to demonstrate that <it>Cjd </it>strains exhibited divergence from <it>Cjj </it>strains NCTC 11168 and RM1221 in many of the intraspecies hypervariable regions. Moreover, multiple metabolic, transport and virulence functions (e.g. cytolethal distending toxin) were shown to be absent in the <it>Cjd </it>strains examined.</p> <p>Conclusion</p> <p>Our data demonstrate that <it>Cjd </it>are phylogenetically distinct from <it>Cjj </it>strains. Using the CGI approach, we identified subsets of absent genes from amongst the <it>C. jejuni </it>genes that provide clues as to the potential evolutionary origin and unusual pathogenicity of <it>Cjd</it>.</p

The effect of nose geometry on the aerothermodynamic environment of shuttle entry configurations

The effect was studied of nose geometry on the transition criteria for the windward boundary layer, on the extent of separation, on the heat transfer perturbation due to the canopy, and on the surface pressure and the heat transfer in the separated region. The data for each of these problems is analyzed. A literature review that concentrates on separation and the leeward flow-field is presented