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Full-Text Articles in Physics
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, …
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.
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 …
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 …