1,316 research outputs found

    Entanglement enhancement and postselection for two atoms interacting with thermal light

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    The evolution of entanglement for two identical two-level atoms coupled to a resonant thermal field is studied for two different families of input states. Entanglement enhancement is predicted for a well defined region of the parameter space of one of these families. The most intriguing result is the possibility of probabilistic production of maximally entangled atomic states even if the input atomic state is factorized and the corresponding output state is separable.Comment: accepted for publication in J. Phys.

    Topology and Phases in Fermionic Systems

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    There can exist topological obstructions to continuously deforming a gapped Hamiltonian for free fermions into a trivial form without closing the gap. These topological obstructions are closely related to obstructions to the existence of exponentially localized Wannier functions. We show that by taking two copies of a gapped, free fermionic system with complex conjugate Hamiltonians, it is always possible to overcome these obstructions. This allows us to write the ground state in matrix product form using Grassman-valued bond variables, and show insensitivity of the ground state density matrix to boundary conditions.Comment: 4 pages, see also arxiv:0710.329

    To study the association of high sensitivity C-reactive protein with metabolic syndrome

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    Background: Metabolic Syndrome is a constellation of dyslipidemia (elevated triglycerides, low high-density lipoproteins (HDL)), elevation of arterial blood pressure (BP), dysregulated glucose homeostasis, and increased abdominal obesity.Methods: We studied the association of high sensitivity C-reactive protein with metabolic syndrome by case-control method in our tertiary care hospital in West U.P.Results: The mean age of cases and controls was 52.6 ± 7.7 and 51.4±7.0 years, respectively. There were 25 (50%) male and 25 (50%) female in case groups, and 27 (54%) males and 23 (46%) females in control group. Our analysis revelaed that there was a significant association between hs-CRP and the central obesity when compared in case-control group (3.57 vs 0.96 mg/L) (p value <0.001). There was no significant association between hs-CRP and high triglycerides, hypertension, diabetes, and reduced high density lipoprotein cholesterol.Conclusions: Raised hsCRP level can be considered as a surrogate marker of chronic inflammation in patients with metabolic syndrome

    Prevalence of peripheral artery disease in diabetes mellitus: research article

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    Background: Peripheral artery disease is a major macrovascular complication of diabetes mellitus. Patients with diabetes mellitus have an increased prevalence of PAD. The ankle brachial pressure index is an easy, non invasive and often under utilised tool for diagnosis of PAD.Methods: In the present study, 100 patients from Western Uttar Pradesh with diabetes mellitus were enrolled to find out prevalence of peripheral vascular disease using ankle brachial pressure index and study the associated risk factors.Results: 59 percent of the subjects were female and 41 percent were male. Ankle-brachial index (ABI) examination of patients indicated Abnormal (ABI= <0.9), in 40 cases.Conclusions: it can be concluded that peripheral vascular disease in Diabetes Mellitus is more commonly associated than is generally believed

    Operator monotones, the reduction criterion and the relative entropy

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    We introduce the theory of operator monotone functions and employ it to derive a new inequality relating the quantum relative entropy and the quantum conditional entropy. We present applications of this new inequality and in particular we prove a new lower bound on the relative entropy of entanglement and other properties of entanglement measures.Comment: Final version accepted for publication, added references in reference [1] and [13

    On Late Time Tails in an Extreme Reissner-Nordstr\"om Black Hole: Frequency Domain Analysis

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    In this brief note, we revisit the study of the leading order late time decay tails of massless scalar perturbations outside an extreme Reissner-Nordstr\"om black hole. Previous authors have analysed this problem in the time domain; we analyse the problem in the frequency domain. We first consider initial perturbations with generic regular behaviour across the horizon on characteristic surfaces. For this set-up, we reproduce some of the previous results of Sela [arXiv:1510.06169] using Fourier methods. Next, we consider related initial data on t=\mbox{const} hypersurfaces, and present decay results at timelike infinity, near future null infinity, and near the future horizon. Along the way, using the r∗→−r∗r_* \to -r_* inversion symmetry of the extreme Reissner-Nordstr\"om spacetime, we relate the higher multipole Aretakis and Newman-Penrose constants for a massless scalar in this background.Comment: 22 pages; 2 figure

    A network-aware framework for energy-efficient data acquisition in wireless sensor networks

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    Wireless sensor networks enable users to monitor the physical world at an extremely high fidelity. In order to collect the data generated by these tiny-scale devices, the data management community has proposed the utilization of declarative data-acquisition frameworks. While these frameworks have facilitated the energy-efficient retrieval of data from the physical environment, they were agnostic of the underlying network topology and also did not support advanced query processing semantics. In this paper we present KSpot+, a distributed network-aware framework that optimizes network efficiency by combining three components: (i) the tree balancing module, which balances the workload of each sensor node by constructing efficient network topologies; (ii) the workload balancing module, which minimizes data reception inefficiencies by synchronizing the sensor network activity intervals; and (iii) the query processing module, which supports advanced query processing semantics. In order to validate the efficiency of our approach, we have developed a prototype implementation of KSpot+ in nesC and JAVA. In our experimental evaluation, we thoroughly assess the performance of KSpot+ using real datasets and show that KSpot+ provides significant energy reductions under a variety of conditions, thus significantly prolonging the longevity of a WSN
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