Single-copy entanglement in a gapped quantum spin chain

The single-copy entanglement of a given many-body system is defined [J. Eisert and M. Cramer, Phys. Rev. A. 72, 042112 (2005)] as the maximal entanglement deterministically distillable from a bipartition of a single specimen of that system. For critical (gapless) spin chains, it was recently shown that this is exactly half the von Neumann entropy [R. Orus, J. I. Latorre, J. Eisert, and M. Cramer, Phys. Rev. A 73, 060303(R) (2006)], itself defined as the entanglement distillable in the asymptotic limit: i.e. given an infinite number of copies of the system. It is an open question as to what the equivalent behaviour for gapped systems is. In this paper, I show that for the paradigmatic spin-S Affleck-Kennedy-Lieb-Tasaki chain (the archetypal gapped chain), the single-copy entanglement is equal to the von Neumann entropy: i.e. all the entanglement present may be distilled from a single specimen.Comment: Typos corrected; accepted for publication in Phys. Rev. Lett.; comments welcom

Decoherence-based exploration of d-dimensional one-way quantum computation

We study the effects of amplitude and phase damping decoherence in d-dimensional one-way quantum computation (QC). Our investigation shows how information transfer and entangling gate simulations are affected for d>=2. To understand motivations for extending the one-way model to higher dimensions, we describe how d-dimensional qudit cluster states deteriorate under environmental noise. In order to protect quantum information from the environment we consider the encoding of logical qubits into physical qudits and compare entangled pairs of linear qubit-cluster states with single qudit clusters of equal length and total dimension. Our study shows a significant reduction in the performance of one-way QC for d>2 in the presence of Markovian type decoherence models.Comment: 8 pages, 11 figures, RevTeX

The Detergent Evaluation Methods and the Washing Machine(PART II)

AIC model selection table and associated coefficients for hermit warbler 2013 for all models combined. Column names for the model coefficients use the following notation: coefficient = parameter(covariate) and standard error = SEparameter(covariate). Parameter abbreviations are p = detection probability, psi = initial occupancy, col = colonization/settlement, ext = extinction/vacancy. Parameter(Int) refers to the intercept. ‘nPars’ is the number of parameters estimated in the model. Each model is ranked by its AIC score, which represents how well the model fits the data. A lower ∆AIC (delta) value is indicative of a better model. The probability that the model (of the models tested) would best explain the data is indicated by AICwt

Telephone administered cognitive behaviour therapy for treatment of obsessive compulsive disorder: randomised controlled non-inferiority trial

This is a freely-available open access publication. Please cite the published version which is available via the DOI link in this record.To compare the effectiveness of cognitive behaviour therapy delivered by telephone with the same therapy given face to face in the treatment of obsessive compulsive disorder.NHS Executive North West (Research and Development Fund

Swift heavy ion irradiation of GaSb: from ion tracks to nano-porous networks

Ion track formation, amorphisation, and the formation of porosity in crystalline GaSb induced by 185 MeV $^{197}$Au swift heavy ion irradiation is investigated as a function of fluence and irradiation angle relative to the surface normal. RBS/C and SAXS reveal an ion track radius between 3 nm and 5 nm. The observed pore morphology and saturation swelling of GaSb films shows a strong irradiation angle dependence. Raman spectroscopy and scanning electron microscopy show that the ion tracks act as a source of strain in the material leading to macroscopic plastic flow at high fluences and off normal irradiation. The results are consistent with the ion hammering model for glasses. Furthermore, wide angle X-ray scattering reveals the formation of nano crystallites inside otherwise amorphous GaSb after the onset of porosity

Theory of Two-Dimensional Josephson Arrays in a Resonant Cavity

We consider the dynamics of a two-dimensional array of underdamped Josephson junctions placed in a single-mode resonant cavity. Starting from a well-defined model Hamiltonian, which includes the effects of driving current and dissipative coupling to a heat bath, we write down the Heisenberg equations of motion for the variables of the Josephson junction and the cavity mode, extending our previous one-dimensional model. In the limit of large numbers of photons, these equations can be expressed as coupled differential equations and can be solved numerically. The numerical results show many features similar to experiment. These include (i) self-induced resonant steps (SIRS's) at voltages V = (n hbar Omega)/(2e), where Omega is the cavity frequency, and n is generally an integer; (ii) a threshold number N_c of active rows of junctions above which the array is coherent; and (iii) a time-averaged cavity energy which is quadratic in the number of active junctions, when the array is above threshold. Some differences between the observed and calculated threshold behavior are also observed in the simulations and discussed. In two dimensions, we find a conspicuous polarization effect: if the cavity mode is polarized perpendicular to the direction of current injection in a square array, it does not couple to the array and there is no power radiated into the cavity. We speculate that the perpendicular polarization would couple to the array, in the presence of magnetic-field-induced frustration. Finally, when the array is biased on a SIRS, then, for given junction parameters, the power radiated into the array is found to vary as the square of the number of active junctions, consistent with expectations for a coherent radiation.Comment: 11 pages, 8 eps figures, submitted to Phys. Rev

The Application of Multispectral Techniques to Analytical Electron Microscopy

The York multispectral analytical electron microscope (MULSAM) was the first instrument specifically designed to acquire and process multiple Auger, X-ray, backscattered electron, elastically scattered electron, scanning electron microscopy (SEM) and specimen absorption current images simultaneously. Analyzing combinations of these signals with multispectral correlation techniques yields more information than would normally be obtained by treating each image separately. This paper reports some of the multispectral methods we have investigated at York which may be of use to other workers. Included are (1) a method that corrects for beam current fluctuations during long acquisition runs which is based on the anti-correlation between SEM and specimen current images, (2) the classification of topography for crystalline specimens by correlation partitioning of backscattered electron images and (3) the enhancement of surface state contrast in multi spectral scanning tunneling microscopy (STM) images using the Hotelling transform. The last example is intended to demonstrate that these techniques can also be applied to other fields in microscopy

第829回千葉医学会例会・第8回千葉精神科集談会

AIC model selection table and associated coefficients for Hammond's flycatcher 2012 for all models combined. Column names for the model coefficients use the following notation: coefficient = parameter(covariate) and standard error = SEparameter(covariate). Parameter abbreviations are p = detection probability, psi = initial occupancy, col = colonization/settlement, ext = extinction/vacancy. Parameter(Int) refers to the intercept. ‘nPars’ is the number of parameters estimated in the model. Each model is ranked by its AIC score, which represents how well the model fits the data. A lower ∆AIC (delta) value is indicative of a better model. The probability that the model (of the models tested) would best explain the data is indicated by AICwt

Topographic, Hydraulic, and Vegetative Controls on Bar and Island Development in Mixed Bedrock‐Alluvial, Multichanneled, Dryland Rivers

We investigate processes of bedrock‐core bar and island development in a bedrock‐influenced anastomosed reach of the Sabie River, Kruger National Park (KNP), eastern South Africa. For sites subject to alluvial stripping during an extreme flood event (~4470‐5630 m3 s‐1) in 2012, pre‐ and post‐flood aerial photographs and LiDAR data, 2D morphodynamic simulations, and field observations reveal that the thickest surviving alluvial deposits tend to be located over bedrock topographic lows. At a simulated peak discharge (~4500 m3 s‐1), most sediment (sand, fine gravel) is mobile but localized deposition on bedrock topographic highs is possible. At lower simulated discharges (<1000 m3 s‐1), topographic highs are not submerged, and deposition occurs in lower elevation areas, particularly in areas disconnected from the main channels during falling stage. Field observations suggest that in addition to discharge, rainwash between floods may redistribute sediments from bedrock topographic highs to lower elevation areas, and also highlight the critical role of vegetation colonization in bar stability, and in trapping of additional sediment and organics. These findings challenge the assumptions of preferential deposition on topographic highs that underpin previous analyses of KNP river dynamics, and are synthesized in a new conceptual model that demonstrates how initial bedrock topographic lows become topographic highs (bedrock core‐bars and islands) in the latter stages of sediment accumulation. The model provides particular insight into the development of mixed bedrock‐alluvial anastomosing along the KNP rivers, but similar processes of bar/island development likely occur along numerous other bedrock‐influenced rivers across dryland southern Africa and farther afield

Forest degradation drives widespread avian habitat and population declines

In many regions of the world, forest management has reduced old forest and simplified forest structure and composition. We hypothesized that such forest degradation has resulted in long-term habitat loss for forest-associated bird species of eastern Canada (130,017 km2) which, in turn, has caused bird-population declines. Despite little change in overall forest cover, we found substantial reductions in old forest as a result of frequent clear-cutting and a broad-scale transformation to intensified forestry. Back-cast species distribution models revealed that breeding habitat loss occurred for 66% of the 54 most common species from 1985 to 2020 and was strongly associated with reduction in old age classes. Using a long-term, independent dataset, we found that habitat amount predicted population size for 94% of species, and habitat loss was associated with population declines for old-forest species. Forest degradation may therefore be a primary cause of biodiversity decline in managed forest landscapes