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Ying Wang, Yu Zhou, Shuyu Zhou
We study the sonic horizon phenomena of the oscillating Bose-Einstein condensates in isotropic harmonic potential. Based on the Gross-Pitaevskii equation model and variational method, we derive the original analytical formula for the criteria and lifetime of the formation of the sonic horizon, demonstrating pictorially the interaction parameter dependence for the occur- rence of the sonic horizon and damping effect of the system distribution width. Our analytical results corroborate quantitatively the particular features of the sonic horizon reported in previous numerical study...
December 6, 2016: Scientific Reports
R P M J W Notermans, R J Rengelink, W Vassen
We observe a dramatic difference in optical line shapes of a ^{4}He Bose-Einstein condensate and a ^{3}He degenerate Fermi gas by measuring the 1557-nm 2 ^{3}S-2 ^{1}S magnetic dipole transition (8 Hz natural linewidth) in an optical dipole trap. The 15 kHz FWHM condensate line shape is only broadened by mean field interactions, whereas the degenerate Fermi gas line shape is broadened to 75 kHz FWHM due to the effect of Pauli exclusion on the spatial and momentum distributions. The asymmetric optical line shapes are observed in excellent agreement with line shape models for the quantum degenerate gases...
November 18, 2016: Physical Review Letters
Nikolay D Kondratyuk, Genri E Norman, Vladimir V Stegailov
Diffusion is one of the key subjects of molecular modeling and simulation studies. However, there is an unresolved lack of consistency between Einstein-Smoluchowski (E-S) and Green-Kubo (G-K) methods for diffusion coefficient calculations in systems of complex molecules. In this paper, we analyze this problem for the case of liquid n-triacontane. The non-conventional long-time tails of the velocity autocorrelation function (VACF) are found for this system. Temperature dependence of the VACF tail decay exponent is defined...
November 28, 2016: Journal of Chemical Physics
R I Khakimov, B M Henson, D K Shin, S S Hodgman, R G Dall, K G H Baldwin, A G Truscott
Ghost imaging is a counter-intuitive phenomenon-first realized in quantum optics-that enables the image of a two-dimensional object (mask) to be reconstructed using the spatio-temporal properties of a beam of particles with which it never interacts. Typically, two beams of correlated photons are used: one passes through the mask to a single-pixel (bucket) detector while the spatial profile of the other is measured by a high-resolution (multi-pixel) detector. The second beam never interacts with the mask. Neither detector can reconstruct the mask independently, but temporal cross-correlation between the two beams can be used to recover a 'ghost' image...
November 30, 2016: Nature
Karol Bartkiewicz, Antonín Černoch, Karel Lemr, Adam Miranowicz, Franco Nori
Temporal steering is a form of temporal correlation between the initial and final state of a quantum system. It is a temporal analogue of the famous Einstein-Podolsky-Rosen (spatial) steering. We demonstrate, by measuring the photon polarization, that temporal steering allows two parties to verify if they have been interacting with the same particle, even if they have no information about what happened with the particle in between the measurements. This is the first experimental study of temporal steering. We also performed experimental tests, based on the violation of temporal steering inequalities, of the security of two quantum key distribution protocols against individual attacks...
November 30, 2016: Scientific Reports
Jan Beyer-Westendorf, Anthonie W A Lensing, Roopen Arya, Henri Bounameaux, Alexander T Cohen, Philip S Wells, Saskia Middeldorp, Peter Verhamme, Rodney Hughes, Nils Kucher, Akos F Pap, Mila Trajanovic, Martin H Prins, Paolo Prandoni, Jeffrey I Weitz
BACKGROUND: The results of the EINSTEIN-DVT/PE and AMPLIFY trials, which compared rivaroxaban and apixaban with conventional anticoagulation therapy for acute venous thromboembolism (VTE), respectively, are often compared. However, the trials differed in duration of therapy (3-12 and 6months, respectively) and in patient selection (few exclusion criteria and more stringent exclusion criteria, respectively). METHODS: To determine the effect of these methodological differences on outcomes, the patients enrolled in EINSTEIN-DVT/PE were divided into 2 cohorts; the 5253 patients that matched the exclusion criteria for AMPLIFY and were treated for at least 6months (cohort 1) and the 2368 patients who would have been ineligible for AMPLIFY (cohort 2)...
November 21, 2016: Thrombosis Research
S Abend, M Gebbe, M Gersemann, H Ahlers, H Müntinga, E Giese, N Gaaloul, C Schubert, C Lämmerzahl, W Ertmer, W P Schleich, E M Rasel
We demonstrate a quantum gravimeter by combining the advantages of an atom chip for the generation, delta-kick collimation, and coherent manipulation of freely falling Bose-Einstein condensates (BECs) with an innovative launch mechanism based on Bloch oscillations and double Bragg diffraction. Our high-contrast BEC interferometer realizes tens of milliseconds of free fall in a volume as little as a one centimeter cube and paves the way for measurements with sub-μGal accuracies in miniaturized, robust devices...
November 11, 2016: Physical Review Letters
E Estrecho, T Gao, S Brodbeck, M Kamp, C Schneider, S Höfling, A G Truscott, E A Ostrovskaya
Diabolical points (spectral degeneracies) can naturally occur in spectra of two-dimensional quantum systems and classical wave resonators due to simple symmetries. Geometric Berry phase is associated with these spectral degeneracies. Here, we demonstrate a diabolical point and the corresponding Berry phase in the spectrum of hybrid light-matter quasiparticles-exciton-polaritons in semiconductor microcavities. It is well known that sufficiently strong optical pumping can drive exciton-polaritons to quantum degeneracy, whereby they form a macroscopically populated quantum coherent state similar to a Bose-Einstein condensate...
November 25, 2016: Scientific Reports
Qing Sun, Jie Hu, Lin Wen, W-M Liu, G Juzeliūnas, An-Chun Ji
We study the ground-state behavior of a Bose-Einstein Condensate (BEC) in a Raman-laser-assisted one-dimensional (1D) optical lattice potential forming a multilayer system. We find that, such system can be described by an effective model with spin-orbit coupling (SOC) of pseudospin (N-1)/2, where N is the number of layers. Due to the intricate interplay between atomic interactions, SOC and laser-assisted tunnelings, the ground-state phase diagrams generally consist of three phases-a stripe, a plane wave and a normal phase with zero-momentum, touching at a quantum tricritical point...
November 24, 2016: Scientific Reports
Rodolfo Paula Leite, Rodrigo Freitas, Rodolfo Azevedo, Maurice de Koning
The Uhlenbeck-Ford (UF) model was originally proposed for the theoretical study of imperfect gases, given that all its virial coefficients can be evaluated exactly, in principle. Here, in addition to computing the previously unknown coefficients B11 through B13, we assess its applicability as a reference system in fluid-phase free-energy calculations using molecular simulation techniques. Our results demonstrate that, although the UF model itself is too soft, appropriately scaled Uhlenbeck-Ford (sUF) models provide robust reference systems that allow accurate fluid-phase free-energy calculations without the need for an intermediate reference model...
November 21, 2016: Journal of Chemical Physics
Ranjini Srinivasan, Rachel Weller, Anjali Chelliah, Andrew J Einstein
Kawasaki disease is a well-known cause of acquired cardiac disease in the pediatric and adult population, most prevalent in Japan but also seen commonly in the United States. In the era of intravenous immunoglobulin (IVIG) treatment, the morbidity associated with this disease has decreased, but it remains a serious illness. Here we present the case of an adolescent, initially diagnosed with Kawasaki disease as an infant, that progressed to giant aneurysm formation and calcification of the coronary arteries...
2016: Case Reports in Pediatrics
Samuel A Einstein, Bradley P Weegman, Jennifer P Kitzmann, Klearchos K Papas, Michael Garwood
Transplantation of macroencapsulated tissue-engineered grafts (TEGs) is being investigated as a treatment for type 1 diabetes, but there is a critical need to measure TEG viability both in vitro and in vivo. Oxygen deficiency is the most critical issue preventing widespread implementation of TEG transplantation and delivery of supplemental oxygen (DSO) has been shown to enhance TEG survival and function in vivo. In this study, we demonstrate the first use of oxygen-17 magnetic resonance spectroscopy ((17) O-MRS) to measure the oxygen consumption rate (OCR) of TEGs and show that in addition to providing therapeutic benefits to TEGs, DSO with (17) O2 can also enable measurements of TEG viability...
November 21, 2016: Biotechnology and Bioengineering
Sudhir Kumar Das, Debashis Majhi, Prabhat Kumar Sahu, Moloy Sarkar
Analysis of time-resolved fluorescence anisotropy data in light of the Stokes-Einstein-Debye hydrodynamic description reveals significant decoupling of rotational motion of the solute and the viscosity of the medium for a hydroxyl-functionalized ionic liquid (IL). This behavior and NMR experiments indicate that the hydroxyl-functionalized IL is more heterogeneous than other structurally similar ILs. Considering that recent theoretical investigations have demonstrated that the jump dynamics and hydrogen-bond fluctuations are closely related in viscous media, in such a case the hydrodynamic description can provide inconsistent results, and the present inapplicability of the hydrodynamics description in explaining solute rotation in a viscous hydroxyl-functionalized IL perhaps provides experimental support to the role of orientational jumps and hydrogen bond formation in that event...
November 17, 2016: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Mengkai Li, Chen Wang, Miaoling Yau, James R Bolton, Zhimin Qiang
A mini-fluidic VUV/UV photoreaction system (MVPS) was developed in our previous study, and it was demonstrated as a powerful tool for studies on pollutant degradation by the VUV/UV process. In this study, we investigated the VUV/UV photodegradation of sulfamethazine (SMN), one of the most frequently detected antibiotics in the environment. The determination methods of photochemical kinetic parameters (e.g., photon fluence-based rate constant and quantum yield) were developed based on the MVPS. The photon fluence-based reaction rate constants for SMN degradation by UV alone and VUV/UV processes were determined as 0...
January 1, 2017: Water Research
Jaclyn M Einstein, Gene W Yeo
No abstract text is available yet for this article.
November 11, 2016: Science
Zhan Wu, Long Zhang, Wei Sun, Xiao-Tian Xu, Bao-Zong Wang, Si-Cong Ji, Youjin Deng, Shuai Chen, Xiong-Jun Liu, Jian-Wei Pan
Cold atoms with laser-induced spin-orbit (SO) interactions provide a platform to explore quantum physics beyond natural conditions of solids. Here we propose and experimentally realize two-dimensional (2D) SO coupling and topological bands for a rubidium-87 degenerate gas through an optical Raman lattice, without phase-locking or fine-tuning of optical potentials. A controllable crossover between 2D and 1D SO couplings is studied, and the SO effects and nontrivial band topology are observed by measuring the atomic cloud distribution and spin texture in momentum space...
October 7, 2016: Science
Kevin L Greason
No abstract text is available yet for this article.
December 2016: Journal of Thoracic and Cardiovascular Surgery
Junru Li, Wujie Huang, Boris Shteynas, Sean Burchesky, Furkan Çağrı Top, Edward Su, Jeongwon Lee, Alan O Jamison, Wolfgang Ketterle
We propose and demonstrate a new approach for realizing spin-orbit coupling with ultracold atoms. We use orbital levels in a double-well potential as pseudospin states. Two-photon Raman transitions between left and right wells induce spin-orbit coupling. This scheme does not require near resonant light, features adjustable interactions by shaping the double-well potential, and does not depend on special properties of the atoms. A pseudospinor Bose-Einstein condensate spontaneously acquires an antiferromagnetic pseudospin texture, which breaks the lattice symmetry similar to a supersolid...
October 28, 2016: Physical Review Letters
B Naylor, M Brewczyk, M Gajda, O Gorceix, E Maréchal, L Vernac, B Laburthe-Tolra
We study the impact of spin-exchange collisions on the dynamics of Bose-Einstein condensation by rapidly cooling a chromium multicomponent Bose gas. Despite relatively strong spin-dependent interactions, the critical temperature for Bose-Einstein condensation is reached before the spin degrees of freedom fully thermalize. The increase in density due to Bose-Einstein condensation then triggers spin dynamics, hampering the formation of condensates in spin-excited states. Small metastable spinor condensates are, nevertheless, produced, and they manifest in strong spin fluctuations...
October 28, 2016: Physical Review Letters
N Galamba
We study the structural and dynamic transformations of SPC/E water with temperature, through molecular dynamics (MD), and discuss the non-Arrhenius behavior of the transport properties and orientational dynamics, and the magnitude of the breakdown of the Stokes-Einstein (SE) and the Stokes-Einstein-Debye (SED) relations, in the light of these transformations. Our results show that deviations from Arrhenius behavior of the self-diffusion at low temperatures cannot be exclusively explained by the reduction of water defects (interstitial waters) and the increase of the local tetrahedrality, thus, suggesting the importance of the slowdown of collective rearrangements...
January 11, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
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