A very brief introduction to quantum computing and quantum information theory for mathematicians

This is a very brief introduction to quantum computing and quantum information theory, primarily aimed at geometers. Beyond basic definitions and examples, I emphasize aspects of interest to geometers, especially connections with asymptotic representation theory. Proofs of most statements can be found in standard references

Species status of Neisseria gonorrhoeae: Evolutionary and epidemiological inferences from multilocus sequence typing

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited - Copyright @ 2007 Bennett et al; licensee BioMed Central Ltd.Background: Various typing methods have been developed for Neisseria gonorrhoeae, but none provide the combination of discrimination, reproducibility, portability, and genetic inference that allows the analysis of all aspects of the epidemiology of this pathogen from a single data set. Multilocus sequence typing (MLST) has been used successfully to characterize the related organisms Neisseria meningitidis and Neisseria lactamica. Here, the same seven locus Neisseria scheme was used to characterize a diverse collection of N. gonorrhoeae isolates to investigate whether this method would allow differentiation among isolates, and to distinguish these three species. Results: A total of 149 gonococcal isolates were typed and submitted to the Neisseria MLST database. Although relatively few (27) polymorphisms were detected among the seven MLST loci, a total of 66 unique allele combinations (sequence types, STs), were observed, a number comparable to that seen among isolate collections of the more diverse meningococcus. Patterns of genetic variation were consistent with high levels of recombination generating this diversity. There was no evidence for geographical structuring among the isolates examined, with isolates collected in Liverpool, UK, showing levels of diversity similar to a global collection of isolates. There was, however, evidence that populations of N. meningitidis, N. gonorrhoeae and N. lactamica were distinct, with little support for frequent genetic recombination among these species, with the sequences from the gdh locus alone grouping the species into distinct clusters. Conclusion: The seven loci Neisseria MLST scheme was readily adapted to N. gonorrhoeae isolates, providing a highly discriminatory typing method. In addition, these data permitted phylogenetic and population genetic inferences to be made, including direct comparisons with N. meningitidis and N. lactamica. Examination of these data demonstrated that alleles were rarely shared among the three species. Analysis of variation at a single locus, gdh, provided a rapid means of identifying misclassified isolates and determining whether mixed cultures were present.This study is funded by the Wellcome Trust and European Unio

Factors affecting the f× Q product of 3C-SiC microstrings: What is the upper limit for sensitivity?

© 2016 AIP Publishing LLC. The fn×Q (Hz) is a crucial sensitivity parameter for micro-electro-mechanical sensing. We have recently shown a fn×Q product of ∼1012Hz for microstrings made of cubic silicon carbide on silicon, establishing a new state-of-the-art and opening new frontiers for mass sensing applications. In this work, we analyse the main parameters influencing the frequency and quality factor of silicon carbide microstrings (material properties, microstring geometry, clamping condition, and environmental pressure) and investigate the potential for approaching the theoretical upper limit. We indicate that our previous result is only about a factor 2 lower than the thermoelastic dissipation limit. For fully reaching this upper limit, a substantial reduction of the defects in the silicon carbide thin film would be required, while maintaining a high residual tensile stress in the perfect-clamped strings

On the nature of the omega tri-layer periodicity in rapidly cooled Ti-15Mo

High angle annular dark field (HAADF) images of the omega phase in metastable beta titanium alloys exhibit tri-layered periodicity. However, it is unclear if this indicates preferential site occupation, or is related to the structural modification of omega formation. Here, the periodicity was studied using a combination of HAADF imaging and electron energy loss spectroscopy. The results show that there is no preferential site occupancy or ordering and that the observed intensity variations are related to the imaging conditions.This work was supported by the Rolls-Royce/EPSRC Strategic Partnership (EP/H022309/1, EP/H500375/1 & EP/M005607/1).This is the final version. It was first published by Elsevier at http://www.sciencedirect.com/science/article/pii/S1359646215002213

Operator entanglement of two-qubit joint unitary operations revisited: Schmidt number approach

Operator entanglement of two-qubit joint unitary operations is revisited. Schmidt number is an important attribute of a two-qubit unitary operation, and may have connection with the entanglement measure of the unitary operator. We found the entanglement measure of two-qubit unitary operators is classified by the Schmidt number of the unitary operators. The exact relation between the operator entanglement and the parameters of the unitary operator is clarified too.Comment: To appear in the Brazilian Journal of Physic

Scaling of Entanglement close to a Quantum Phase Transitions

In this Letter we discuss the entanglement near a quantum phase transition by analyzing the properties of the concurrence for a class of exactly solvable models in one dimension. We find that entanglement can be classified in the framework of scaling theory. Further, we reveal a profound difference between classical correlations and the non-local quantum correlation, entanglement: the correlation length diverges at the phase transition, whereas entanglement in general remains short ranged.Comment: 4 pages, 4 figures, revtex. Stylistic changes and format modifie

Quantum uniqueness

In the classical world one can construct two identical systems which have identical behavior and give identical measurement results. We show this to be impossible in the quantum domain. We prove that after the same quantum measurement two different quantum systems cannot yield always identical results, provided the possible measurement results belong to a non orthogonal set. This is interpreted as quantum uniqueness - a quantum feature which has no classical analog. Its tight relation with objective randomness of quantum measurements is discussed.Comment: Presented at 4th Feynman festival, June 22-26, 2009, in Olomouc, Czech Republic

Structure and optical properties of Lu <inf>2</inf>SiO <inf>5</inf>:Ce phosphor thin films

Luminescent, cerium doped Lu 2SiO 5 thin films with C2/c symmetry have been prepared by pulsed laser deposition (PLD) at temperatures much lower than the crystallization temperature (2150°C) of the corresponding bulk crystals. The PLD grown films show the typical luminescence resulting from the Ce 3+ 5d-4f transition. Maximum luminescence efficiency was observed for films prepared at an oxygen partial pressure of 200 mTorr at 600°C. These conditions reflect a balance between Ce 4+/Ce 3+ interconversion and the crystalline quality of the films. The results indicate that PLD offers a low temperature deposition technique for complex oxide phosphor materials. © 2006 American Institute of Physics

Growth hormone as concomitant treatment in severe fibromyalgia associated with low IGF-1 serum levels. A pilot study

<p>Abstract</p> <p>Background</p> <p>There is evidence of functional growth hormone (GH) deficiency, expressed by means of low insulin-like growth factor 1 (IGF-1) serum levels, in a subset of fibromyalgia patients. The efficacy of GH versus placebo has been previously suggested in this population. We investigated the efficacy and safety of low dose GH as an adjunct to standard therapy in the treatment of severe, prolonged and well-treated fibromyalgia patients with low IGF-1 levels.</p> <p>Methods</p> <p>Twenty-four patients were enrolled in a randomized, open-label, best available care-controlled study. Patients were randomly assigned to receive either 0.0125 mg/kg/d of GH subcutaneously (titrated depending on IGF-1) added to standard therapy or standard therapy alone during one year. The number of tender points, the Fibromyalgia Impact Questionnaire (FIQ) and the EuroQol 5D (EQ-5D), including a Quality of Life visual analogic scale (EQ-VAS) were assessed at different time-points.</p> <p>Results</p> <p>At the end of the study, the GH group showed a 60% reduction in the mean number of tender points (pairs) compared to the control group (p < 0.05; 3.25 ± 0.8 <it>vs</it>. 8.25 ± 0.9). Similar improvements were observed in FIQ score (p < 0.05) and EQ-VAS scale (p < 0.001). There was a prompt response to GH administration, with most patients showing improvement within the first months in most of the outcomes. The concomitant administration of GH and standard therapy was well tolerated, and no patients discontinued the study due to adverse events.</p> <p>Conclusion</p> <p>The present findings indicate the advantage of adding a daily GH dose to the standard therapy in a subset of severe fibromyalgia patients with low IGF-1 serum levels.</p> <p>Trial Registration</p> <p>NCT00497562 (ClinicalTrials.gov).</p

Quantum Candies and Quantum Cryptography

The field of quantum information is becoming more known to the general public. However, effectively demonstrating the concepts underneath quantum science and technology to the general public can be a challenging job. We investigate, extend, and much expand here "quantum candies" (invented by Jacobs), a pedagogical model for intuitively describing some basic concepts in quantum information, including quantum bits, complementarity, the no-cloning principle, and entanglement. Following Jacob's quantum candies description of the well known quantum key distribution protocol BB84, we explicitly demonstrate various additional quantum cryptography protocols using quantum candies in an approachable manner. The model we investigate can be a valuable tool for science and engineering educators who would like to help the general public to gain more insights about quantum science and technology: most parts of this paper, including many protocols for quantum cryptography, are expected to be easily understandable by a layperson without any previous knowledge of mathematics, physics, or cryptography.Comment: To be presented at the 9th International Conference on the Theory and Practice of Natural Computing (TPNC 2020; postponed and merged with TPNC 2021). The final authenticated publication is available online at https://doi.org/10.1007/978-3-030-63000-3_