30,759 research outputs found

    Deep learning of topological phase transitions from entanglement aspects

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    The one-dimensional p-wave superconductor proposed by Kitaev has long been a classic example for understanding topological phase transitions through various methods, such as examining the Berry phase, edge states of open chains, and, in particular, aspects from quantum entanglement of ground states. In order to understand the amount of information carried in the entanglement-related quantities, here we study topological phase transitions of the model with emphasis of using the deep learning approach. We feed different quantities, including Majorana correlation matrices (MCMs), entanglement spectra (ES) or entanglement eigenvectors (EE) originating from Block correlation matrices, into the deep neural networks for training, and investigate which one could be the most useful input format in this approach. We find that ES is information that is too compressed compared to MCM or EE. MCM and EE can provide us abundant information to recognize not only the topological phase transitions in the model but also phases of matter with different U(1) gauges, which is not reachable by using ES only

    Fluctuation Effects in High Sheet Resistance Superconducting Films

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    As the normal state sheet resistance, RnR_n, of a thin film superconductor increases, its superconducting properties degrade. For Rnh/4e2R_n\simeq h/4e^2 superconductivity disappears and a transition to a nonsuperconducting state occurs. We present electron tunneling and transport measurements on ultrathin, homogeneously disordered superconducting films in the vicinity of this transition. The data provide strong evidence that fluctuations in the amplitude of the superconducting order parameter dominate the tunneling density of states and the resistive transitions in this regime. We briefly discuss possible sources of these amplitude fluctuation effects. We also describe how the data suggest a novel picture of the superconductor to nonsuperconductor transition in homogeneous 2D systems.Comment: 11 pages, 5 figure

    Undetermined states: how to find them and their applications

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    We investigate the undetermined sets consisting of two-level, multi-partite pure quantum states, whose reduced density matrices give absolutely no information of their original states. Two approached of finding these quantum states are proposed. One is to establish the relation between codewords of the stabilizer quantum error correction codes (SQECCs) and the undetermined states. The other is to study the local complementation rules of the graph states. As an application, the undetermined states can be exploited in the quantum secret sharing scheme. The security is guaranteed by their undetermineness.Comment: 6 pages, no figur

    Evaluation of innovative sprayed-concrete-lined tunnelling

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    The front-shunt tunnel was the first tunnel of the Terminal 5 project at Heathrow to be constructed, and was the first section of sprayed-concrete-lined (SCL) tunnel to be constructed using the method known as LaserShell. This innovation represented a significant deviation from the methods previously used in SCL construction. Therefore it was subjected to a careful examination before and during construction using sophisticated 3D numerical modelling and monitoring during construction. The paper presents typical results from surface settlement levelling, inclinometers and extensometers, pressure cells and tunnel lining displacement measurements, and comments on the performance of the methods and instruments used. The paper then presents the methodology and typical results of the numerical modelling, and shows that the predictions of displacements and stresses compared well with the field measurements. In terms of the control of ground deformations and structural safety the tunnel performed well

    The use of graft materials in vaginal pelvic floor surgery

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    ObjectiveTo review recent literature on graft materials used in vaginal pelvic floor surgery.MethodsA Pubmed‐search (“anterior vaginal wall” or “cystocele”), (“posterior vaginal wall” or “rectocele”) and (“vaginal vault” or “pelvic prolapse”) and (“mesh” or “erosion” or “graft” or “synthetic”) from 1995 to 2005 was performed; recent reviews [Birch C. The use of prosthetics in pelvic reconstructive surgery. Best Pract Res Clin Obstet Gynaecol 2005;19:979–91 [1]; Maher C, Baessler K. Surgical management of anterior vaginal wall prolapse: an evidence‐based literature review. Int Urogynecol J Pelvic Floor Dysfunct 2005 (May 25) [Electronic Publication] [2]; Maher C, Baessler K. Surgical management of posterior vaginal wall prolapse: an evidence‐based literature review. Int Urogynecol J Pelvic Floor Dysfunct 2006;17:84–8 [3]; Altman D, Mellgren A, Zetterstrom J. Rectocele repair using biomaterial augmentation: current documentation and clinical experience. Obstet Gynecol Surv 2005;60:753–60 [4]] were added.ResultThere are few prospective randomized trials that prove the benefit of implanting grafts in vaginal pelvic floor surgery. Many articles are retrospective case series with small sample sizes or incomplete outcome variables. Serious complications such as erosions are often not mentioned. Inconsistent or unclear criteria for anatomic cure make it difficult to compare outcomes. Quality of life issues such as dyspareunia, urinary or bowel symptoms are often ignored.ConclusionDue to a lack of well‐designed prospective randomized trials, recommendations for using graft materials in vaginal reconstructive surgery cannot be made. At this time, grafts should have limited use in a carefully selected patient population.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135429/1/ijgo279.pd

    Draft Genome Sequence of Mycobacterium arupense Strain GUC1.

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    We report the draft genome sequence of Mycobacterium arupense strain GUC1 from a sputum sample of a patient with bronchiectasis. This is the first draft genome sequence of Mycobacterium arupense, a rapidly growing nonchromogenic mycobacteria

    Draft Genome Sequence of Mycobacterium elephantis Strain Lipa.

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    We report the draft genome sequence of Mycobacterium elephantis strain Lipa from a sputum sample of a patient with pulmonary disease. This is the first draft genome sequence of M. elephantis, a rapidly growing mycobacterium

    Draft Genome Sequence of Mycobacterium obuense Strain UC1, Isolated from Patient Sputum.

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    We report the draft genome sequence of Mycobacterium obuense strain UC1 from a patient sputum sample. This is the first draft genome sequence of Mycobacterium obuense, a rapidly growing scotochromogenic mycobacterium
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