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Luca Baiotti, Luciano Rezzolla
The merger of binary neutron-stars systems combines in a single process: extreme gravity, copious emission of gravitational waves, complex microphysics, and electromagnetic processes that can lead to astrophysical signatures observable at the largest redshifts. We review here the recent progress in understanding what could be considered Einstein's richest laboratory, highlighting in particular the numerous significant advances of the last decade. Although special attention is paid to the status of models, techniques, and results for fully general-relativistic dynamical simulations, a review is also offered on initial data and advanced simulations with approximate treatments of gravity...
March 20, 2017: Reports on Progress in Physics
Jeffrey I Weitz, Anthonie W A Lensing, Martin H Prins, Rupert Bauersachs, Jan Beyer-Westendorf, Henri Bounameaux, Timothy A Brighton, Alexander T Cohen, Bruce L Davidson, Hervé Decousus, Maria C S Freitas, Gerlind Holberg, Ajay K Kakkar, Lloyd Haskell, Bonno van Bellen, Akos F Pap, Scott D Berkowitz, Peter Verhamme, Philip S Wells, Paolo Prandoni
Background Although many patients with venous thromboembolism require extended treatment, it is uncertain whether it is better to use full- or lower-intensity anticoagulation therapy or aspirin. Methods In this randomized, double-blind, phase 3 study, we assigned 3396 patients with venous thromboembolism to receive either once-daily rivaroxaban (at doses of 20 mg or 10 mg) or 100 mg of aspirin. All the study patients had completed 6 to 12 months of anticoagulation therapy and were in equipoise regarding the need for continued anticoagulation...
March 18, 2017: New England Journal of Medicine
Thomas E Collett, David Bacon
Probing the relative speeds of gravitational waves and light acts as an important test of general relativity and alternative theories of gravity. Measuring the arrival time of gravitational waves (GWs) and electromagnetic (EM) counterparts can be used to measure the relative speeds, but only if the intrinsic time lag between emission of the photons and gravitational waves is well understood. Here we suggest a method that does not make such an assumption, using future strongly lensed GW events and EM counterparts; Biesiada et al...
March 3, 2017: Physical Review Letters
Yang Liu, Manish Vashishta, Pavle Djuricanin, Sida Zhou, Wei Zhong, Tony Mittertreiner, David Carty, Takamasa Momose
We have demonstrated that a supersonic beam of methyl radicals (CH_{3}) in the ground rotational state of both para and ortho species has been slowed down to standstill with a magnetic molecular decelerator, and successfully captured spatially in an anti-Helmholtz magnetic trap for >1  s. The trapped CH_{3} radicals have a mean translational temperature of about 200 mK with an estimated density of >5.0×10^{7}  cm^{-3}. The methyl radical is an ideal system for the study of cold molecules not only because of its high reactivities at low temperatures, but also because further cooling below 1 mK is plausible via sympathetic cooling with ultracold atoms...
March 3, 2017: Physical Review Letters
Soumya Patnaik, Mahek Shah, Yaser Alhamshari, Pradhum Ram, Ritika Puri, Marvin Lu, Percy Balderia, John B Imms, Obiora Maludum, Vincent M Figueredo
BACKGROUND: Chest pain is one of the most common presentations to a hospital, and appropriate triaging of these patients can be challenging. The HEART score has been used for such purposes in some countries and only a few validation studies from the USA are available. We aim to determine the utility of the HEART score in patients presenting with chest pain to an inner-city hospital in the USA. PATIENTS AND METHODS: We retrospectively screened 417 consecutive patients admitted with chest pain to the observation/telemetry units at Einstein Medical Center Philadelphia...
March 10, 2017: Coronary Artery Disease
F I López-Bara, F López-Aguilar
Low energy excitation states in magnetic structures of the so-called spin-ices are produced via spin flips among contiguous tetrahedra of their crystal structure. These spin flips generate entities which mimic magnetic dipoles in every two tetrahedra according to the dumbbell model. When the temperature increases, the spin-flip processes are transmitted in the lattice, generating so-called Dirac strings, which constitute structural entities that can present mimetic behavior similar to that of magnetic monopoles...
March 13, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Vassiliki Kalogera, Albert Lazzarini
A unique window on the universe opened on September 14, 2015, with direct detection of gravitational waves by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors. This event culminated a half-century effort around the globe to develop terrestrial detectors of adequate sensitivity to achieve this goal. It also happened appropriately only a few months before the centennial of Einstein's final paper introducing the general theory of relativity. This detection provided the surprising discovery of a coalescing pair of "heavy" black holes (more massive than [Formula: see text] M[Formula: see text]) leading to the formation of a spinning [Formula: see text]62 solar mass black hole...
March 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
Srinivasulu Sonati, Savita Bhutoria, Muthuchidambaran Prabhakaran, Seetharama A Acharya
A new variant of HbS, HbS-Einstein with a deletion of segment α23-26 in the B-helix, has been assembled by semisynthetic approach. B-helix of the α chain of cis αβ-dimer of HbS plays dominant role in the quinary interactions of deoxy HbS dimer. This B-helix is the primary scaffold that provides the orientation for the side chains of contact residues of this intermolecular contact domain. The design of HbS-Einstein has been undertaken to map the influence of perturbation of molecular surface topology and the flexibility of surface residues in the polymerization...
March 1, 2017: Journal of Biomolecular Structure & Dynamics
Manoj K Jana, Koushik Pal, Avinash Warankar, Pankaj Mandal, Umesh V Waghmare, Kanishka Biswas
Understanding the nature of chemical bonding and lattice dynamics together with their influence on phonon-transport is essential to explore and design crystalline solids with ultralow thermal conductivity for various applications including thermoelectrics. TlInTe2, with interlocked rigid and weakly bound substructures, exhibits lattice thermal conductivity as low as ca. 0.5 W/mK near room temperature, owing to rattling dynamics of weakly bound Tl cations. Large displacements of Tl cations along the c-axis, driven by electrostatic repulsion between localized electron clouds on Tl and Te ions, are akin to those of rattling guests in caged-systems...
March 14, 2017: Journal of the American Chemical Society
Lukas Reichsöllner, Andreas Schindewolf, Tetsu Takekoshi, Rudolf Grimm, Hanns-Christoph Nägerl
We demonstrate a generally applicable technique for mixing two-species quantum degenerate bosonic samples in the presence of an optical lattice, and we employ it to produce low-entropy samples of ultracold ^{87}Rb^{133}Cs Feshbach molecules with a lattice filling fraction exceeding 30%. Starting from two spatially separated Bose-Einstein condensates of Rb and Cs atoms, Rb-Cs atom pairs are efficiently produced by using the superfluid-to-Mott insulator quantum phase transition twice, first for the Cs sample, then for the Rb sample, after nulling the Rb-Cs interaction at a Feshbach resonance's zero crossing...
February 17, 2017: Physical Review Letters
Jing Kong, Zheng Bo, Huachao Yang, Jinyuan Yang, Xiaorui Shuai, Jianhua Yan, Kefa Cen
The behavior of ion diffusion in nano-confined spaces and its temperature dependence provide important fundamental information about electric double-layer capacitors (EDLCs) employing nano-sized active materials. In this work, the ion diffusion coefficients of NaCl electrolyte confined within neutral and charged graphene nanochannels at different temperatures are investigated using molecular dynamics simulations. The results show that ions confined in neutral nanochannels diffuse faster (along the graphene surfaces) than those in bulk solution, which could be attributed to the relatively smaller concentration in confined spaces and the solvophobic nature of graphene surfaces...
March 3, 2017: Physical Chemistry Chemical Physics: PCCP
Julian Léonard, Andrea Morales, Philip Zupancic, Tilman Esslinger, Tobias Donner
The concept of a supersolid state combines the crystallization of a many-body system with dissipationless flow of the atoms from which it is built. This quantum phase requires the breaking of two continuous symmetries: the phase invariance of a superfluid and the continuous translational invariance to form the crystal. Despite having been proposed for helium almost 50 years ago, experimental verification of supersolidity remains elusive. A variant with only discrete translational symmetry breaking on a preimposed lattice structure-the 'lattice supersolid'-has been realized, based on self-organization of a Bose-Einstein condensate...
March 1, 2017: Nature
Jun-Ru Li, Jeongwon Lee, Wujie Huang, Sean Burchesky, Boris Shteynas, Furkan Çağrı Top, Alan O Jamison, Wolfgang Ketterle
Supersolidity combines superfluid flow with long-range spatial periodicity of solids, two properties that are often mutually exclusive. The original discussion of quantum crystals and supersolidity focused on solid (4)He and triggered extensive experimental efforts that, instead of supersolidity, revealed exotic phenomena including quantum plasticity and mass supertransport. The concept of supersolidity was then generalized from quantum crystals to other superfluid systems that break continuous translational symmetry...
March 1, 2017: Nature
H Zhong, G Fläschner, A Schwarz, R Wiesendanger, P Christoph, T Wagner, A Bick, C Staarmann, B Abeln, K Sengstock, C Becker
We describe the construction of an apparatus designed to realize a hybrid quantum system comprised of a cryogenically cooled mechanical oscillator and ultra-cold (87)Rb atoms coupled via light. The outstanding feature of our instrument is an in situ adjustable asymmetric all-fiber membrane-in-the-middle cavity located inside an ultra-high vacuum dilution refrigerator based cryostat. We show that Bose-Einstein condensates of N=2×10(6) atoms can be produced in less than 20 s and demonstrate a single photon optomechanical coupling strength of g0=2π×9 kHz employing a high-stress Si3N4 membrane with a mechanical quality factor Qm>10(7) at a cavity setup temperature of TMiM = 480 mK...
February 2017: Review of Scientific Instruments
Agnieszka Połatyńska, Karolina Tomczyk, Mikołaj Pochylski, Gerd Meier, Jacek Gapinski, Ewa Banachowicz, Tomasz Śliwa, Adam Patkowski
In this work, we describe new experimental setups for Fluorescence Correlation Spectroscopy (FCS) where a long working distance objective is used. Using these setups, FCS measurements in a broad temperature range for a small sample volume of about 50 μl can be performed. The use of specially designed cells and a dry long working distance objective was essential for avoiding temperature gradients in the sample. The performance of the new setups and a traditional FCS setup with immersion objectives is compared...
February 28, 2017: Journal of Chemical Physics
Jakub Spiechowicz, Marcin Kostur, Jerzy Łuczka
We study diffusion properties of an inertial Brownian motor moving on a ratchet substrate, i.e., a periodic structure with broken reflection symmetry. The motor is driven by an unbiased time-periodic symmetric force that takes the system out of thermal equilibrium. For selected parameter sets, the system is in a non-chaotic regime in which we can identify a non-monotonic dependence of the diffusion coefficient on temperature: for low temperature, it initially increases as the temperature grows, passes through its local maximum, next starts to diminish reaching its local minimum, and finally it monotonically increases in accordance with the Einstein linear relation...
February 2017: Chaos
Vladimir Oliker
The SQM is a versatile methodology for designing freeform optics for irradiance redistribution. Recently it has often been applied in design of freeform lenses, mirrors and diffractive optical elements. Still, many questions regarding theory and performance of optics designed with the SQM are open. Here we investigate theoretically plano-freeform refractive lenses designed with the SQM when an incident collimated beam must be transformed into a beam illuminating with prescribed irradiances a large number of pixels on a flat screen...
February 20, 2017: Optics Express
Clifford Cheung, Grant N Remmen
We study the Gauss-Bonnet (GB) term as the leading higher-curvature correction to pure Einstein gravity. Assuming a tree-level ultraviolet completion free of ghosts or tachyons, we prove that the GB term has a nonnegative coefficient in dimensions greater than 4. Our result follows from unitarity of the spectral representation for a general ultraviolet completion of the GB term.
February 3, 2017: Physical Review Letters
Alicia J Kollár, Alexander T Papageorge, Varun D Vaidya, Yudan Guo, Jonathan Keeling, Benjamin L Lev
Phase transitions, where observable properties of a many-body system change discontinuously, can occur in both open and closed systems. By placing cold atoms in optical cavities and inducing strong coupling between light and excitations of the atoms, one can experimentally study phase transitions of open quantum systems. Here we observe and study a non-equilibrium phase transition, the condensation of supermode-density-wave polaritons. These polaritons are formed from a superposition of cavity photon eigenmodes (a supermode), coupled to atomic density waves of a quantum gas...
February 17, 2017: Nature Communications
David M Rogers
This work examines the thermodynamic consequences of the repeated partial projection model for coupling a quantum system to an arbitrary series of environments under feedback control. This paper provides observational definitions of heat and work that can be realized in current laboratory setups. In contrast to other definitions, it uses only properties of the environment and the measurement outcomes, avoiding references to the "measurement" of the central system's state in any basis. These definitions are consistent with the usual laws of thermodynamics at all temperatures, while never requiring complete projective measurement of the entire system...
January 2017: Physical Review. E
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