Read by QxMD icon Read


M Naritsuka, P F S Rosa, Yongkang Luo, Y Kasahara, Y Tokiwa, T Ishii, S Miyake, T Terashima, T Shibauchi, F Ronning, J D Thompson, Y Matsuda
Unconventional superconductivity and magnetism are intertwined on a microscopic level in a wide class of materials. A new approach to this most fundamental and hotly debated issue focuses on the role of interactions between superconducting electrons and bosonic fluctuations at the interface between adjacent layers in heterostructures. Here we fabricate hybrid superlattices consisting of alternating atomic layers of the heavy-fermion superconductor CeCoIn_{5} and antiferromagnetic (AFM) metal CeRhIn_{5}, in which the AFM order can be suppressed by applying pressure...
May 4, 2018: Physical Review Letters
Guiming Pang, Michael Smidman, Jinglei Zhang, Lin Jiao, Zongfa Weng, Emilian M Nica, Ye Chen, Wenbing Jiang, Yongjun Zhang, Wu Xie, Hirale S Jeevan, Hanoh Lee, Philipp Gegenwart, Frank Steglich, Qimiao Si, Huiqiu Yuan
The nature of the pairing symmetry of the first heavy fermion superconductor CeCu2 Si2 has recently become the subject of controversy. While CeCu2 Si2 was generally believed to be a [Formula: see text]-wave superconductor, recent low-temperature specific heat measurements showed evidence for fully gapped superconductivity, contrary to the nodal behavior inferred from earlier results. Here, we report London penetration depth measurements, which also reveal fully gapped behavior at very low temperatures. To explain these seemingly conflicting results, we propose a fully gapped [Formula: see text] band-mixing pairing state for CeCu2 Si2 , which yields very good fits to both the superfluid density and specific heat, as well as accounting for a sign change of the superconducting order parameter, as previously concluded from inelastic neutron scattering results...
May 8, 2018: Proceedings of the National Academy of Sciences of the United States of America
David Rosen, Jingfeng Jiang
Our primary objective of this work was to design and test a new time-of-flight (TOF) method that allows measurements of shear wave speed (SWS) following impulsive excitation in soft tissues. Particularly, under the assumption of the local plane shear wave, this work named the Fourier-domain shift matching (FDSM) method, estimates SWS by aligning a series of shear waveforms either temporally or spatially using a solution space deduced by characteristic curves of the well-known 1-D wave equation. The proposed SWS estimation method was tested using computer-simulated data, and tissue-mimicking phantom and ex vivo tissue experiments...
May 2018: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Daniel O'Malley
Making predictions about flow and transport in an aquifer requires knowledge of the heterogeneous properties of the aquifer such as permeability. Computational methods for inverse analysis are commonly used to infer these properties from quantities that are more readily observable such as hydraulic head. We present a method for computational inverse analysis that utilizes a type of quantum computer called a quantum annealer. While quantum computing is in an early stage compared to classical computing, we demonstrate that it is sufficiently developed that it can be used to solve certain subsurface flow problems...
May 2, 2018: Scientific Reports
Kee Soo Ha, Jae Young Choi, Jo Won Jung, Nam Kyun Kim
Few hemodynamic comparison studies on various types of Fontan operation have been reported. The objective of this study was to perform hemodynamic comparisons for flow size and volume in three types of Fontan operation: atriopulmonary connection (APC), lateral tunnel (LT), and extracardiac conduit (ECC). Forty patients with Fontan operation (8 with APC Fontan, 22 with LT Fontan, and 10 with ECC Fontan) were enrolled. Velocity time integral (VTI) and average peak velocity (APV) were assessed according to cardiac and respiratory cycles in SVC, IVC, hepatic vein, conduit, LPA, and RPA using direct intravenous Doppler echocardiography...
April 18, 2018: Pediatric Cardiology
Kota Katsumi, Naoto Tsuji, Yuki I Hamada, Ryusuke Matsunaga, John Schneeloch, Ruidan D Zhong, Genda D Gu, Hideo Aoki, Yann Gallais, Ryo Shimano
We investigate the terahertz (THz)-pulse-driven nonlinear response in the d-wave cuprate superconductor Bi_{2}Sr_{2}CaCu_{2}O_{8+x} (Bi2212) using a THz pump near-infrared probe scheme in the time domain. We observe an oscillatory behavior of the optical reflectivity that follows the THz electric field squared and is markedly enhanced below T_{c}. The corresponding third-order nonlinear effect exhibits both A_{1g} and B_{1g} symmetry components, which are decomposed from polarization-resolved measurements. A comparison with a BCS calculation of the nonlinear susceptibility indicates that the A_{1g} component is associated with the Higgs mode of the d-wave order parameter...
March 16, 2018: Physical Review Letters
Andrey Y Lokhov, Marc Vuffray, Sidhant Misra, Michael Chertkov
Reconstruction of the structure and parameters of an Ising model from binary samples is a problem of practical importance in a variety of disciplines, ranging from statistical physics and computational biology to image processing and machine learning. The focus of the research community shifted toward developing universal reconstruction algorithms that are both computationally efficient and require the minimal amount of expensive data. We introduce a new method, interaction screening, which accurately estimates model parameters using local optimization problems...
March 2018: Science Advances
Bartłomiej Gardas, Jacek Dziarmaga, Wojciech H Zurek, Michael Zwolak
The shift of interest from general purpose quantum computers to adiabatic quantum computing or quantum annealing calls for a broadly applicable and easy to implement test to assess how quantum or adiabatic is a specific hardware. Here we propose such a test based on an exactly solvable many body system-the quantum Ising chain in transverse field-and implement it on the D-Wave machine. An ideal adiabatic quench of the quantum Ising chain should lead to an ordered broken symmetry ground state with all spins aligned in the same direction...
March 14, 2018: Scientific Reports
C E Matt, D Sutter, A M Cook, Y Sassa, M Månsson, O Tjernberg, L Das, M Horio, D Destraz, C G Fatuzzo, K Hauser, M Shi, M Kobayashi, V N Strocov, T Schmitt, P Dudin, M Hoesch, S Pyon, T Takayama, H Takagi, O J Lipscombe, S M Hayden, T Kurosawa, N Momono, M Oda, T Neupert, J Chang
The minimal ingredients to explain the essential physics of layered copper-oxide (cuprates) materials remains heavily debated. Effective low-energy single-band models of the copper-oxygen orbitals are widely used because there exists no strong experimental evidence supporting multi-band structures. Here, we report angle-resolved photoelectron spectroscopy experiments on La-based cuprates that provide direct observation of a two-band structure. This electronic structure, qualitatively consistent with density functional theory, is parametrised by a two-orbital ([Formula: see text] and [Formula: see text]) tight-binding model...
March 6, 2018: Nature Communications
A A Kalenyuk, A Pagliero, E A Borodianskyi, A A Kordyuk, V M Krasnov
Josephson current provides a phase-sensitive tool for probing the pairing symmetry. Here we present an experimental study of high-quality Josephson junctions between a conventional s-wave superconductor Nb and a multiband iron-pnictide Ba_{1-x}Na_{x}Fe_{2}As_{2}. Junctions exhibit a large enough critical current density to preclude the d-wave symmetry of the order parameter in the pnictide. However, the I_{c}R_{n} product is very small ≃3μV, which is not consistent with the sign-preserving s_{++} symmetry either...
February 9, 2018: Physical Review Letters
Igor Boettcher, Igor F Herbut
We investigate unconventional superconductivity in three-dimensional electronic systems with the chemical potential close to a quadratic band touching point in the band dispersion. Short-range interactions can lead to d-wave superconductivity, described by a complex tensor order parameter. We elucidate the general structure of the corresponding Ginzburg-Landau free energy and apply these concepts to the case of an isotropic band touching point. For a vanishing chemical potential, the ground state of the system is given by the superconductor analogue of the uniaxial nematic state, which features line nodes in the excitation spectrum of quasiparticles...
February 2, 2018: Physical Review Letters
Swagatam Nayak, Sanjeev Kumar
We show that the extended attractive Hubbard model on a square lattice allows for a variety of superconducting phases, including exotic mixed-symmetry phases with [Formula: see text] and [Formula: see text] symmetries, and a novel [Formula: see text] state. The calculations are performed within the Hartree-Fock Bardeen-Cooper-Schrieffer framework. The ground states of the mean-field Hamiltonian are obtained via a minimization scheme that relaxes the symmetry constraints on the superconducting solutions, hence allowing for a mixing of s-, p- and d-wave order parameters...
April 4, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
András Gyenis, Benjamin E Feldman, Mallika T Randeria, Gabriel A Peterson, Eric D Bauer, Pegor Aynajian, Ali Yazdani
Layered material structures play a key role in enhancing electron-electron interactions to create correlated metallic phases that can transform into unconventional superconducting states. The quasi-two-dimensional electronic properties of such compounds are often inferred indirectly through examination of bulk properties. Here we use scanning tunneling microscopy to directly probe in cross-section the quasi-two-dimensional electronic states of the heavy fermion superconductor CeCoIn5 . Our measurements reveal the strong confined nature of quasiparticles, anisotropy of tunneling characteristics, and layer-by-layer modulated behavior of the precursor pseudogap gap phase...
February 7, 2018: Nature Communications
Jingxiang Zhao, Qiang Gu
We study the two-dimensional Hubbard model with the Rashba type spin-orbit coupling within and beyond the mean-field theory. The antiferromagnetic ground state for the model at half-filling and the Cooper pairing induced by antiferromagnetic spin fluctuations near half-filling are examined based on the random-phase approximation. We show that the antiferromagnetic order is suppressed and the magnetic susceptibility turns out to be anisotropic in the presence of the spin-orbit coupling. Energy spectrums of transverse spin fluctuations are obtained and the effective interactions between holes mediated by antiferromagnetic spin fluctuations are deduced in the case of low hole doping...
January 17, 2018: Scientific Reports
D F Agterberg, T Shishidou, J O'Halloran, P M R Brydon, M Weinert
Monolayer FeSe exhibits the highest transition temperature among the iron based superconductors and appears to be fully gapped, seemingly consistent with s-wave superconductivity. Here, we develop a theory for the superconductivity based on coupling to fluctuations of checkerboard magnetic order (which has the same translation symmetry as the lattice). The electronic states are described by a symmetry based k·p-like theory and naturally account for the states observed by angle resolved photoemission spectroscopy...
December 29, 2017: Physical Review Letters
Xiang Chen, Julian L Schmehr, Zahirul Islam, Zach Porter, Eli Zoghlin, Kenneth Finkelstein, Jacob P C Ruff, Stephen D Wilson
Materials that exhibit both strong spin-orbit coupling and electron correlation effects are predicted to host numerous new electronic states. One prominent example is the Jeff  = 1/2 Mott state in Sr2 IrO4 , where introducing carriers is predicted to manifest high temperature superconductivity analogous to the S = 1/2 Mott state of La2 CuO4 . While bulk superconductivity currently remains elusive, anomalous quasiparticle behaviors paralleling those in the cuprates such as pseudogap formation and the formation of a d-wave gap are observed upon electron-doping Sr2 IrO4 ...
January 9, 2018: Nature Communications
D G Mazzone, S Raymond, J L Gavilano, P Steffens, A Schneidewind, G Lapertot, M Kenzelmann
Unconventional superconductivity in many materials is believed to be mediated by magnetic fluctuations. It is an open question how magnetic order can emerge from a superconducting condensate and how it competes with the magnetic spin resonance in unconventional superconductors. Here we study a model d-wave superconductor that develops spin-density wave order, and find that the spin resonance is unaffected by the onset of static magnetic order. This result suggests a scenario, in which the resonance in Nd_{0...
November 3, 2017: Physical Review Letters
A DeGrush, A Maschinot, T Akdogan, R Alarcon, W Bertozzi, E Booth, T Botto, J R Calarco, B Clasie, C Crawford, K Dow, M Farkhondeh, R Fatemi, O Filoti, W Franklin, H Gao, E Geis, S Gilad, D K Hasell, P Karpius, M Kohl, H Kolster, T Lee, J Matthews, K McIlhany, N Meitanis, R Milner, J Rapaport, R Redwine, J Seely, A Shinozaki, A Sindile, S Širca, E Six, T Smith, B Tonguc, C Tschalär, E Tsentalovich, W Turchinetz, Y Xiao, W Xu, Z-L Zhou, V Ziskin, T Zwart
We report the measurement of the beam-vector and tensor asymmetries A_{ed}^{V} and A_{d}^{T} in quasielastic (e[over →],e^{'}p) electrodisintegration of the deuteron at the MIT-Bates Linear Accelerator Center up to missing momentum of 500  MeV/c. Data were collected simultaneously over a momentum transfer range 0.1<Q^{2}<0.5  (GeV/c)^{2} with the Bates Large Acceptance Spectrometer Toroid using an internal deuterium gas target polarized sequentially in both vector and tensor states. The data are compared with calculations...
November 3, 2017: Physical Review Letters
Yilin Wang, Hongming Weng, Liang Fu, Xi Dai
The magnetic properties of the pyrochlore iridate material Eu_{2}Ir_{2}O_{7} (5d^{5}) have been studied based on first principles calculations, where the crystal field splitting Δ, spin-orbit coupling (SOC) λ, and Coulomb interaction U within Ir 5d orbitals all play significant roles. The ground state phase diagram has been obtained with respect to the strength of SOC and Coulomb interaction U, where a stable antiferromagnetic ground state with all-in-all-out (AIAO) spin structure has been found. In addition, another antiferromagnetic state with energy close to AIAO has also been found to be stable...
November 3, 2017: Physical Review Letters
Yue Cui, Chuyang Shen, Min Deng, Shen Dong, Cheng Chen, Rong Lü, Bo Gao, Meng Khoon Tey, Li You
High partial-wave (l≥2) Feshbach resonance (FR) in an ultracold mixture of ^{85}Rb-^{87}Rb atoms is investigated experimentally aided by a partial-wave insensitive analytic multichannel quantum-defect theory. Two "broad" resonances from coupling between d waves in both the open and closed channels are observed and characterized. One of them shows a fully resolved triplet structure with a splitting ratio well explained by the perturbation to the closed channel due to interatomic spin-spin interaction...
November 17, 2017: Physical Review Letters
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"