366 research outputs found

    Advanced configuration of gravitational-wave interferometer on the base of "sensitive mode" in "white-light cavity"

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    A novel conception of "sensitive mode" (SM) is proposed to apply in gravitational-wave advanced interferometer configuration. The SM is resonant oscillation of electromagnetic field in "white-light cavity", where the resonance line is broadened without decreasing cavity quality. The frequency of the SM is greatly susceptible to the change of cavity length, and the SM is established in a cavity with time constant smaller than a conventional mode. Due to these advantages the sensitivity and bandwidth of AIC can be increased.Comment: 9 pages, 5 figure

    Existence of the Abrikosov vortex state in two-dimensional type-II superconductors without pinning

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    Theory alternative to the vortex lattice melting theories is advertised. The vortex lattice melting theories are science fiction cond-mat/9811051 because the Abrikosov state is not the vortex lattice with crystalline long-range order. Since the fluctuation correction to the Abrikosov solution is infinite in the thermodynamic limit (K.Maki and H.Takayama, 1972) any fluctuation theory of the mixed state should consider a superconductor with finite sizes. Such nonperturbative theory for the easiest case of two-dimensional superconductor in the lowest Landau level approximation is presented in this work. The thermodynamic averages of the spatial average order parameter and of the Abrikosov parameter βa\beta_{a} are calculated. It is shown that the position H_{c4} of the transition into the Abrikosov state (i.e. in the mixed state with long-range phase coherence) depends strongly on sizes of two-dimensional superconductor. Fluctuations eliminate the Abrikosov vortex state in a wide region of the mixed state of thin films with real sizes and without pinning disorders, i.e. H_{c4} << H_{c2}. The latter has experimental corroboration in Phys.Rev.Lett. 75, 2586 (1995).Comment: 4 pages, 0 figure

    Construction of Field Algebras with Quantum Symmetry from Local Observables

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    It has been discussed earlier that ( weak quasi-) quantum groups allow for conventional interpretation as internal symmetries in local quantum theory. From general arguments and explicit examples their consistency with (braid-) statistics and locality was established. This work addresses to the reconstruction of quantum symmetries and algebras of field operators. For every algebra \A of observables satisfying certain standard assumptions, an appropriate quantum symmetry is found. Field operators are obtained which act on a positive definite Hilbert space of states and transform covariantly under the quantum symmetry. As a substitute for Bose/Fermi (anti-) commutation relations, these fields are demonstrated to obey local braid relation.Comment: 50 pages, HUTMP 93-B33

    Steady water waves with multiple critical layers: interior dynamics

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    We study small-amplitude steady water waves with multiple critical layers. Those are rotational two-dimensional gravity-waves propagating over a perfect fluid of finite depth. It is found that arbitrarily many critical layers with cat's-eye vortices are possible, with different structure at different levels within the fluid. The corresponding vorticity depends linearly on the stream function.Comment: 14 pages, 3 figures. As accepted for publication in J. Math. Fluid Mec

    The evolution of galaxy groups and of galaxies therein

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    Properties of groups of galaxies depend sensitively on the algorithm for group selection, and even the most recent catalogs of groups built from redshift-space selection should suffer from projections and infalling galaxies. The cosmo-dynamical evolution of groups from initial Hubble expansion to collapse and virialization leads to a fundamental track (FT) in virial-theorem-M/L vs crossing time. The increased rates of mergers, both direct and after dynamical friction, in groups relative to clusters, explain the higher fraction of elliptical galaxies at given local number density in X-ray selected groups, relative to clusters, even when the hierarchical evolution of groups is considered. Galaxies falling into groups and clusters should later travel outwards to typically 2 virial radii, which is somewhat less than the outermost radius where observed galaxy star formation efficiencies are enhanced relative to field galaxies of same morphological type. An ongoing analysis of the internal kinematics of X-ray selected groups suggests that the radial profiles of line of sight velocity dispersion are consistent with isotropic NFW distributions for the total mass density, with higher (lower) concentrations than LambdaCDM predictions in groups of high (low) mass. The critical mass, at M200 ~ 10^13 M_sun is consistent with possible breaks in the X-ray luminosity-temperature and Fundamental Plane relations. The internal kinematics of groups indicate that the M-T relation of groups should agree with that extrapolated from clusters with no break at the group scale. The analyses of observed velocity dispersion profiles and of the FT both suggest that low velocity dispersion groups (compact and loose, X-ray emitting or undetected) are quite contaminated by chance projections.Comment: Invited review, ESO workshop "Groups of Galaxies in the Nearby Universe", held in Santiago, Chile, 5-9 December 2005, ed. I. Saviane, V. Ivanov & J. Borissova, 16 page

    A Single-Lumen Central Venous Catheter for Continuous and Direct Intra-abdominal Pressure Measurement

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    Background: Abdominal compartment syndrome (ACS) is associated with high morbidity and mortality rates. Therefore, the need for a good diagnostic tool to predict intra-abdominal hypertension (IAH) and progression to ACS is paramount. Bladder pressure (BP) has been used for several years for intra-abdominal pressure (IAP) measurement but has the disadvantage that it is not a continuous measurement. In this study, a single-lumen central venous catheter (CVC) is placed through the abdominal wall into the abdominal cavity to continuously and directly monitor the intra-abdominal pressure (CDIAP). The aim of this study was to evaluate the use of CDIAP to measure BP as a representative of the true IAP. Methods: Both BP and CDIAP were prospectively recorded on a variety of surgical patients admitted to the intensive care unit (ICU) from March 2003 up to December 2004. At the end of the surgical procedure, the CVC was placed through the abdominal wall and connected to a pressure transducer. In addition, the BP was measured through the urine drainage port after clamping the catheter and filling the bladder with 50 ml of 0.9% saline. At least three paired measurements (BP and CDIAP) were performed for at least one day on the ICU in a standardized manner at preset time intervals on each patient. The paired measurements were compared using the Bland-Altman (B-A) method. Data are presented as mean ± standard deviation. Results: Over a period of 22 months (March 2003 until December 2004), 125 paired measurements of both BP and CDIAP were recorded on 25 patients. The mean age was 72.4 ± 6.6 years. Eighteen patients underwent central vascular surgery, and seven patients with peritonitis received laparotomy. The mean CDIAP was 11.4 ± 4.8 (range 2-30) mmHg, and the BP was 12.9 ± 5.3 (range 3-37) mmHg. The mean difference between CDIAP and BP was 1.6 ± 2.7 mmHg. There was an acceptable level of agreement (intraclass correlation 0.82) between IAP measured by BP and IAP measured via CDIAP. Conclusion: Continuous direct intra-abdominal pressure measurement proved that the BP measurement approach of Kron is representative of the IAP. CDIAP measurement is accurate and makes it easier for the nursing staff to be informed of the IAP

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
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