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Articles 1 - 16 of 16
Full-Text Articles in Physical Sciences and Mathematics
Strong Electron-Boson Coupling In The Iron-Based Superconductor Bafe1.9pt0.1as2 Revealed By Infrared Spectroscopy, Zhen Xing, Shanta Saha, J. Paglione, M. M. Qazilbash
Strong Electron-Boson Coupling In The Iron-Based Superconductor Bafe1.9pt0.1as2 Revealed By Infrared Spectroscopy, Zhen Xing, Shanta Saha, J. Paglione, M. M. Qazilbash
Arts & Sciences Articles
Understanding the formation of Cooper pairs in iron-based superconductors is one of the most important topics in condensed matter physics. In conventional superconductors, the electron-phonon interaction leads to the formation of Cooper pairs. In conventional strong-coupling superconductors like lead (Pb), the features due to electron-phonon interaction are evident in the infrared absorption spectra. Here we investigate the infrared absorption spectra of the iron arsenide superconductor BaFe1.9Pt0.1As2. We find that this superconductor has fully gapped (nodeless) Fermi surfaces, and we observe the strong-coupling electron-boson interaction features in the infrared absorption spectra. Through modeling with the Eliashberg function based on Eliashberg theory, …
Asymmetric Hillslope Erosion Following Wildfire In Fourmile Canyon, Colorado, Edward R. Abrahams, James M. Kaste, William Ouimet, David P. Dethier
Asymmetric Hillslope Erosion Following Wildfire In Fourmile Canyon, Colorado, Edward R. Abrahams, James M. Kaste, William Ouimet, David P. Dethier
Arts & Sciences Articles
Infrequent, high-magnitude events cause a disproportionate amount of sediment transport on steep hillslopes, but few quantitative data are available that capture these processes. Here we study the influence of wildfire and hillslope aspect on soil erosion in Fourmile Canyon, Colorado. This region experienced the Fourmile Fire of 2010, strong summer convective storms in 2011 and 2012, and extreme flooding in September 2013. We sampled soils shortly after these events and use fallout radionuclides to trace erosion on polar- and equatorial-facing burned slopes and on a polar-facing unburned slope. Because these radionuclides are concentrated in the upper decimeter of soil, soil …
Topological Changes Of Wave Functions Associated With Hamiltonian Monodromy, C. Chen, John B. Delos
Topological Changes Of Wave Functions Associated With Hamiltonian Monodromy, C. Chen, John B. Delos
Arts & Sciences Articles
Almost everything that happens in classical mechanics also shows up in quantum mechanics when we know where to look for it. A phenomenon in classical mechanics involves topological changes in action-angle loops as a result of passage around a “monodromy circuit.” This phenomenon is known by the short name “Hamiltonian monodromy” (or, more ponderously, “nontrivial monodromy of action and angle variables in integrable Hamiltonian systems”). In this paper, we show a corresponding change in quantum wave functions: These wave functions change their topological structure in the same way that the corresponding classical action-angle loops change.
Low-Cost Wave Characterization Modules For Oil Spill Response, E. D. Skinner, M. M. Rooney, Mark K. Hinders
Low-Cost Wave Characterization Modules For Oil Spill Response, E. D. Skinner, M. M. Rooney, Mark K. Hinders
Arts & Sciences Articles
Marine oil spills can be remediated by mechanical skimmers in calm waters, but performance degrades with increased wave height. We have developed and demonstrated a system that quantifies local wave characteristics with an uncertainty of four inches of heave. Our system is intended for the measurement of wave characteristics during oil spill recovery. It conveys this information to coordinators and responders in real time via WiFi and remote reporting through a satellite network. This information will allow for enhanced situational awareness during an oil spill response, assisting stakeholders and optimizing mechanical skimming operations. Our wave characterization module (WCM) uses accelerometer …
Antineutrino Charged-Current Reactions On Hydrocarbon With Low Momentum Transfer, Minerva Collaboration, L. Aliaga, Michael Kordosky, Jeffrey K. Nelson, A. Norrick, E. Valencia, Et Al.
Antineutrino Charged-Current Reactions On Hydrocarbon With Low Momentum Transfer, Minerva Collaboration, L. Aliaga, Michael Kordosky, Jeffrey K. Nelson, A. Norrick, E. Valencia, Et Al.
Arts & Sciences Articles
We report on multinucleon effects in low momentum transfer (< 0.8 GeV/c) antineutrino interactions on plastic (CH) scintillator. These data are from the 2010-2011 antineutrino phase of the MINERvA experiment at Fermilab. The hadronic energy spectrum of this inclusive sample is well described when a screening effect at a low energy transfer and a two-nucleon knockout process are added to a relativistic Fermi gas model of quasielastic, Delta resonance, and higher resonance processes. In this analysis, model elements introduced to describe previously published neutrino results have quantitatively similar benefits for this antineutrino sample. We present the results as a double-differential cross section to accelerate the investigation of alternate models for antineutrino scattering off nuclei.
A Terbium Chlorobismuthate(Iii) Double Salt: Synthesis, Structure, And Photophysical Properties, John C. Ahern, Aaron D. Nicholas, Andrew W. Kelly, Benny Chan, Robert D. Pike, Howard Patterson
A Terbium Chlorobismuthate(Iii) Double Salt: Synthesis, Structure, And Photophysical Properties, John C. Ahern, Aaron D. Nicholas, Andrew W. Kelly, Benny Chan, Robert D. Pike, Howard Patterson
Arts & Sciences Articles
We report on the structure and luminescence of a double salt trivalent rare earth ion acceptor, Tb3+, with octahedral [BiCl6]3– donor clusters. The novel TbBiCl6·14H2O (1) was prepared from aqueous BiOCl and TbCl3·6H2O. The crystal structure of compound 1 exhibits isolated [BiCl6]3– and [Tb(OH2)8]3+ clusters. Luminescence data show energy transfer from octahedral chlorobismuthate(III) clusters to rare earth metal ions. Density Functional Theory (DFT) calculations show distinctly different emission pathways at high and low excitation energies.
Probing Molecular Dynamics With Hyperpolarized Ultrafast Laplace Nmr Using A Low-Field, Single-Sided Magnet, Jared N. King, Alfredo Fallorina, Justin Yu, Et Al., Tyler K. Meldrum
Probing Molecular Dynamics With Hyperpolarized Ultrafast Laplace Nmr Using A Low-Field, Single-Sided Magnet, Jared N. King, Alfredo Fallorina, Justin Yu, Et Al., Tyler K. Meldrum
Arts & Sciences Articles
Laplace NMR (LNMR) offers deep insights on diffusional and rotational motion of molecules. The so-called “ultrafast” approach, based on spatial data encoding, enables one to carry out a multidimensional LNMR experiment in a single scan, providing from 10 to 1000-fold acceleration of the experiment. Here, we demonstrate the feasibility of ultrafast diffusion–T2 relaxation correlation (D–T2) measurements with a mobile, low-field, relatively low-cost, single-sided NMR magnet. We show that the method can probe a broad range of diffusion coefficients (at least from 10−8 to 10−12 m2 s−1) and reveal multiple components of fluids in heterogeneous …
Isotope Shifts In The 7 S → 8 S Transition Of Francium: Measurements And Comparison To Ab Initio Theory, M. R. Kalita, J. A. Behr, (...), Seth Aubin, Et Al.
Isotope Shifts In The 7 S → 8 S Transition Of Francium: Measurements And Comparison To Ab Initio Theory, M. R. Kalita, J. A. Behr, (...), Seth Aubin, Et Al.
Arts & Sciences Articles
We observe the electric-dipole forbidden 7s→8s transition in the francium isotopes 208−211Fr and 213Fr using a two-photon excitation scheme. We collect the atoms online from an accelerator and confine them in a magneto-optical trap for the measurements. In combination with previous measurements of the 7s→7p1/2 transition we perform a King plot analysis. We compare the thus-determined ratio of the field shift constants (1.228 ± 0.019) to results obtained from new ab initio calculations (1.234 ± 0.010).
Microwave Ac Zeeman Force For Ultracold Atoms, C. T. Fancher, A. J. Pyle, A. P. Rotunno, Seth Aubin
Microwave Ac Zeeman Force For Ultracold Atoms, C. T. Fancher, A. J. Pyle, A. P. Rotunno, Seth Aubin
Arts & Sciences Articles
We measure the ac Zeeman force on an ultracold gas of 87Rb due to a microwave magnetic field targeted to the 6.8 GHz hyperfine splitting of these atoms. An atom chip produces a microwave near field with a strong amplitude gradient, and we observe a force over three times the strength of gravity. Our measurements are consistent with a simple two-level theory for the ac Zeeman effect and demonstrate its resonant, bipolar, and spin-dependent nature. We observe that the dressed-atom eigenstates gradually mix over time and have mapped out this behavior as a function of magnetic field and detuning. We …
Cosmogenic Neutron Production At Daya Bay, Daya Bay Collaboration, (…), R. D. Mckeown, W. Wang, Et Al.
Cosmogenic Neutron Production At Daya Bay, Daya Bay Collaboration, (…), R. D. Mckeown, W. Wang, Et Al.
Arts & Sciences Articles
Neutrons produced by cosmic ray muons are an important background for underground experiments studying neutrino oscillations, neutrinoless double beta decay, dark matter, and other rare-event signals. A measurement of the neutron yield in the three different experimental halls of the Daya Bay Reactor Neutrino Experiment at varying depth is reported. The neutron yield in Daya Bay's liquid scintillator is measured to be Y-n = (10.26 +/- 0.86) x 10(-5), (10.22 +/- 0.87) x 10(-5), and (17.03 +/- 1.22) x 10(-5) mu(-1)g(-1)cm(2) at depths of 250, 265, and 860 meters-water-equivalent. These results are compared to other measurements and the simulated neutron …
Experimental Observation Of Classical Dynamical Monodromy, M. P. Nerem, D. Salmon, Seth Aubin, John B. Delos
Experimental Observation Of Classical Dynamical Monodromy, M. P. Nerem, D. Salmon, Seth Aubin, John B. Delos
Arts & Sciences Articles
A Hamiltonian system is said to have nontrivial monodromy if its fundamental action-angle loops do not return to their initial topological state at the end of a closed circuit in angular momentum-energy space. This process has been predicted to have consequences which can be seen in dynamical systems, called dynamical monodromy. Using an apparatus consisting of a spherical pendulum subject to magnetic potentials and torques, we observe nontrivial monodromy by the associated topological change in the evolution of a loop of trajectories.
Experimental Observation Of Classical Dynamical Monodromy, M. P. Nerem, D. Salmon, S. Aubin, John B. Delos
Experimental Observation Of Classical Dynamical Monodromy, M. P. Nerem, D. Salmon, S. Aubin, John B. Delos
Arts & Sciences Articles
A Hamiltonian system is said to have nontrivial monodromy if its fundamental action-angle loops do not return to their initial topological state at the end of a closed circuit in angular momentum-energy space. This process has been predicted to have consequences which can be seen in dynamical systems, called dynamical monodromy. Using an apparatus consisting of a spherical pendulum subject to magnetic potentials and torques, we observe nontrivial monodromy by the associated topological change in the evolution of a loop of trajectories.
Isoscalar Pi Pi, K(K)Over-Bar, Eta Eta Scattering And The Sigma, F(0),F(2) Mesons From Qcd, Raul A. Briceno, Jozef J. Dudek, Robert G. Edwards, David J. Wilson
Isoscalar Pi Pi, K(K)Over-Bar, Eta Eta Scattering And The Sigma, F(0),F(2) Mesons From Qcd, Raul A. Briceno, Jozef J. Dudek, Robert G. Edwards, David J. Wilson
Arts & Sciences Articles
We present the first lattice QCD study of coupled isoscalar pi pi, K (K) over bar, eta eta S- and D-wave scattering extracted from discrete finite-volume spectra computed on lattices which have a value of the light quark mass corresponding to m(pi) similar to 391 MeV. In the J(P) = 0(+) sector we find analogues of the experimental sigma and f(0)(980) states, where the sigma appears as a stable bound-state below pi pi threshold, and, similar to what is seen in experiment, the f(0)(980) manifests itself as a dip in the pi pi cross section in the vicinity of the …
Crystal Structure And Computational Analysis Of A Two-Dimensional Coordination Polymer, Bii3(Dppeo2)3/2, Andrew W. Kelly, Amelia M. Wheaton, Aaron D. Nicholas, Howard H. Patterson, Robert D. Pike
Crystal Structure And Computational Analysis Of A Two-Dimensional Coordination Polymer, Bii3(Dppeo2)3/2, Andrew W. Kelly, Amelia M. Wheaton, Aaron D. Nicholas, Howard H. Patterson, Robert D. Pike
Arts & Sciences Articles
Catena-poly[fac-triiodobismuth(III)-tris-(µ-ethane-1,2-diylbis(diphenylphosphane oxide-κ2O,O′))], a 2-D sheet network of BiI3 was synthesized from BiI3 and ethane-1,2-diylbis(diphenylphosphane oxide) (DppeO2) in tetrahydrofuran. The crystal structure revealed a trigonal structure with three-fold symmetry at Bi. Bismuth centers show fac-BiI3O3 coordination, with Bi–I = 2.9416(2) Å and Bi–O = 2.4583(17) Å. The I–Bi–I and O–Bi–O angles (95.520(7)° and 79.04(6)°, respectively) indicate trigonal distortion in the Bi octahedron. Bridging DppeO2 ligands centered on inversion centers give rise to a 2-D sheet polymer. The 8.3 Å thick sheets consist of three layers in a sandwich structure. The outer layers are composed of phenyl rings and …
Detecting A Heavy Neutrino Electric Dipole Moment At The Lhc, Marc Sher, Justin R. Stevens
Detecting A Heavy Neutrino Electric Dipole Moment At The Lhc, Marc Sher, Justin R. Stevens
Arts & Sciences Articles
The milliQan Collaboration has proposed to search for millicharged particles by looking for very weakly ionizing tracks in a detector installed in a cavern near the CMS experiment at the LHC. We note that another form of exotica can also yield weakly ionizing tracks. If a heavy neutrino has an electric dipole moment (EDM), then the milliQan experiment may be sensitive to it as well. In particular, writing the general dimension-5 operator for an EDM with a scale of a TeV and a one-loop factor, one finds a potential EDM as high as a few times 10(-17) e-cm, and models …
Highly Repeatable Nanoscale Phase Coexistence In Vanadium Dioxide Films, T. J. Huffman, D. J. Lahneman, (...), M. M. Qazilbash
Highly Repeatable Nanoscale Phase Coexistence In Vanadium Dioxide Films, T. J. Huffman, D. J. Lahneman, (...), M. M. Qazilbash
Arts & Sciences Articles
It is generally believed that in first-order phase transitions in materials with imperfections, the formation of phase domains must be affected to some extent by stochastic (probabilistic) processes. The stochasticity would lead to unreliable performance in nanoscale devices that have the potential to exploit the transformation of physical properties in a phase transition. Here we show that stochasticity at nanometer length scales is completely suppressed in the thermally driven metal-insulator transition (MIT) in sputtered vanadium dioxide (VO2) films. The nucleation and growth of domain patterns of metallic and insulating phases occur in a strikingly reproducible way. The completely deterministic nature …