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Full-Text Articles in Physics
Long-Baseline Neutrino Oscillation Physics Potential Of The Dune Experiment, B. Abi, M. A. Acero, G. Adamov, D. Adams, M. Adinolfi, Z Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andringa, A. Ankowski, M. Antonova, S. Antusch, A. Aranda-Fernandez, A. Ariga, L. O. Arnold, Roberto Petti, Et. Al.
Long-Baseline Neutrino Oscillation Physics Potential Of The Dune Experiment, B. Abi, M. A. Acero, G. Adamov, D. Adams, M. Adinolfi, Z Ahmad, J. Ahmed, T. Alion, S. Alonso Monsalve, C. Alt, J. Anderson, C. Andreopoulos, M. P. Andrews, F. Andringa, A. Ankowski, M. Antonova, S. Antusch, A. Aranda-Fernandez, A. Ariga, L. O. Arnold, Roberto Petti, Et. Al.
Faculty Publications
The sensitivity of the Deep Underground Neutrino Experiment (DUNE) to neutrino oscillation is determined, based on a full simulation, reconstruction, and event selection of the far detector and a full simulation and parameterized analysis of the near detector. Detailed uncertainties due to the flux prediction, neutrino interaction model, and detector effects are included. DUNE will resolve the neutrino mass ordering to a precision of 5σ for δCP values, after 2 years of running with the nominal detector design and beam configuration. It has the potential to observe charge-parity violation in the neutrino sector to a precision of 3 …
A Short Introduction To Numerical Linked-Cluster Expansions, Baoming Tang, Ehsan Khatami, Marcos Rigol
A Short Introduction To Numerical Linked-Cluster Expansions, Baoming Tang, Ehsan Khatami, Marcos Rigol
Faculty Publications
We provide a pedagogical introduction to numerical linked-cluster expansions (NLCEs). We sketch the algorithm for generic Hamiltonians that only connect nearest-neighbor sites in a finite cluster with open boundary conditions. We then compare results for a specific model, the Heisenberg model, in each order of the NLCE with the ones for the finite cluster calculated directly by means of full exact diagonalization. We discuss how to reduce the computational cost of the NLCE calculations by taking into account symmetries and topologies of the linked clusters. Finally, we generalize the algorithm to the thermodynamic limit, and discuss several numerical resummation techniques …
Time Reversal Invariance Violating And Parity Conserving Effects In Neutron-Deuteron Scattering, Young-Ho Song, Rimantas Lazauskas, Vladimir Gudkov
Time Reversal Invariance Violating And Parity Conserving Effects In Neutron-Deuteron Scattering, Young-Ho Song, Rimantas Lazauskas, Vladimir Gudkov
Faculty Publications
Time reversal invariance violating and parity conserving effects for low-energy elastic neutron-deuteronscattering are calculated for meson exchange and effective field theory type potentials in a distorted wave-bornapproximation using realistic hadronic wave functions, obtained by solving three-body Faddeev equations inconfiguration space.
Time Reversal Invariance Violation In Neutron-Deuteron Scattering, Young-Ho Song, Rimantas Lazauskas, Vladimir Gudkov
Time Reversal Invariance Violation In Neutron-Deuteron Scattering, Young-Ho Song, Rimantas Lazauskas, Vladimir Gudkov
Faculty Publications
Time reversal invariance-violating (TRIV) effects in low-energy elastic neutron-deuteron scattering arecalculated using meson exchange and EFT-type TRIV potentials in a distorted-wave Born approximation withrealistic hadronic strong interaction wave functions, obtained by solving the three-body Faddeev equations inconfiguration space. The relation between TRIV and parity-violating observables is discussed.
Growth Direction Modulation And Diameter-Dependent Mobility In Inn Nanowires, Goutam Koley, Zhihua Cai, Ehtesham Bin Quddus, Jie Liu, Muhammad Qazi, Richard A. Webb
Growth Direction Modulation And Diameter-Dependent Mobility In Inn Nanowires, Goutam Koley, Zhihua Cai, Ehtesham Bin Quddus, Jie Liu, Muhammad Qazi, Richard A. Webb
Faculty Publications
Diameter-dependent electrical properties of InN nanowires (NWs) grown by chemical vapor deposition have been investigated. The NWs exhibited interesting properties of coplanar deflection at specific angles, either spontaneously, or when induced by other NWs or lithographically patterned barriers. InN NW-based back-gated field effect transistors (FETs) showed excellent gate control and drain current saturation behaviors. Both NW conductance and carrier mobility calculated from the FET characteristics were found to increase regularly with a decrease in NW diameter. The observed mobility and conductivity variations have been modeled by considering NW surface and core conduction paths.
Parity Violation In Low-Energy Neutron-Deuteron Scattering, Young-Ho Song, Rimantas Lazauskas, Vladimir Gudkov
Parity Violation In Low-Energy Neutron-Deuteron Scattering, Young-Ho Song, Rimantas Lazauskas, Vladimir Gudkov
Faculty Publications
Parity-violating effects for low-energy elastic neutron deuteron scattering are calculated for Desplanques,Donoghue, and Holstein (DDH) and effective field theory types of weak potentials in a distorted-wave Bornapproximation, using realistic hadronic strong interaction wave functions, obtained by solving three-bodyFaddeev equations in configuration space. The resulting relation between physical observables and low-energyconstants can be used to fix low-energy constants from experiments. Potential model dependencies ofparity-violating effects are discussed.
Parity Violation In The N + 3he → 3h + P Reaction: Resonance Approach, Vladimir Gudkov
Parity Violation In The N + 3he → 3h + P Reaction: Resonance Approach, Vladimir Gudkov
Faculty Publications
The method based on microscopic theory of nuclear reactions has been applied for the analysis of parityviolatingeffects in few-body systems. Different parity-violating and parity-conserving asymmetries and theirdependence on neutron energy have been estimated for the n + 3He → 3H + p reaction. The estimated effectsare in a good agreement with available exact calculations.
Faddeev-Type Equations For Three-Body Symmetry Violating Scattering Amplitudes, Vladimir Gudkov, Young-Ho Song
Faddeev-Type Equations For Three-Body Symmetry Violating Scattering Amplitudes, Vladimir Gudkov, Young-Ho Song
Faculty Publications
The equations which relate three-body and two-body symmetry violating scattering amplitudes are derivedin the first order of symmetry violating interactions. They can be used to obtain three-body symmetry violatingscattering amplitudes from two-body symmetry violating scattering amplitudes calculated in low energy effectivefield theory.
Memristive Model Of Amoeba Learning, Yuriy V. Pershin Dr, Steven La Fontaine, Massimiliano Di Ventra
Memristive Model Of Amoeba Learning, Yuriy V. Pershin Dr, Steven La Fontaine, Massimiliano Di Ventra
Faculty Publications
Recently, it was shown that the amoebalike cell Physarum polycephalum when exposed to a pattern of periodic environmental changes learns and adapts its behavior in anticipation of the next stimulus to come. Here we show that such behavior can be mapped into the response of a simple electronic circuit consisting of a LC contour and a memory-resistor (a memristor) to a train of voltage pulses that mimic environment changes. We also identify a possible biological origin of the memristive behavior in the cell. These biological memory features are likely to occur in other unicellular as well as mutlicellular organisms, albeit …
Macrospin Model To Explain The Absence Of Preswitching Oscillations In Magnetic Tunnel Junctions: Fieldlike Spin-Transfer Torque, Samir Garzon, Yaroslaw Bazaliy, Richard A. Webb, Mark Covington, Shehzaad Kaka, Thomas M. Crawford
Macrospin Model To Explain The Absence Of Preswitching Oscillations In Magnetic Tunnel Junctions: Fieldlike Spin-Transfer Torque, Samir Garzon, Yaroslaw Bazaliy, Richard A. Webb, Mark Covington, Shehzaad Kaka, Thomas M. Crawford
Faculty Publications
We show that the absence of preswitching oscillations (“incubation delay”) in magnetic tunnel junctions can be explained within the macrospin model by a sizable fieldlike component of the spin-transfer torque. It is further suggested that measurements of the voltage dependence of tunnel junction switching time in the presence of external easy axis magnetic fields can be used to determine the magnitude and voltage dependence of the fieldlike torque.
Coherent Control Of Nanomagnet Dynamics Via Ultrafast Spin Torque Pulses, Samir Garzon, Longfei Ye, Richard A. Webb, Thomas M. Crawford, Mark Covington, Shehzaad Kaka
Coherent Control Of Nanomagnet Dynamics Via Ultrafast Spin Torque Pulses, Samir Garzon, Longfei Ye, Richard A. Webb, Thomas M. Crawford, Mark Covington, Shehzaad Kaka
Faculty Publications
We demonstrate reliable manipulation of the magnetization dynamics of a precessing nanomagnet by precisely controlling the spin transfer torque on the subnanosecond time scale. Using a simple pulse shaping scheme consisting of two ultrafast spin torque pulses with variable amplitudes and delay, we demonstrate coherent control over the precessional orbits and the ability to tune the switching probability of a nanomagnet at room temperature and 77 K. Our measurements suggest that appropriately shaped spin transfer can be used to efficiently manipulate the orientation of a free layer nanomagnet, thus providing an alternative for spin torque driven spintronic devices.
Community Detection In Complex Networks By Dynamical Simplex Evolution, Vladimir Gudkov, V. Montealegre, S. Nussinov, Z. Nussinov
Community Detection In Complex Networks By Dynamical Simplex Evolution, Vladimir Gudkov, V. Montealegre, S. Nussinov, Z. Nussinov
Faculty Publications
We benchmark the dynamical simplex evolution (DSE) method with several of the currently available algorithms to detect communities in complex networks by comparing correctly identified nodes for different levels of "fuzziness" of random networks composed of well-defined communities. The potential benefits of the DSE method to detect hierarchical substructures in complex networks are discussed.
Asymmetry Of Recoil Protons In Neutron Β Decay, Vladimir Gudkov
Asymmetry Of Recoil Protons In Neutron Β Decay, Vladimir Gudkov
Faculty Publications
A complete analysis of proton recoil asymmetry in neutron decay in the first order of radiative and recoil corrections is presented. The possible contributions from new physics are calculated in terms of low energy coupling constants, and the sensitivity of the measured asymmetry to models beyond the Standard Model are discussed.
A Geowall With Physics And Astronomy Applications, Phillip Dukes, Dan Bruton
A Geowall With Physics And Astronomy Applications, Phillip Dukes, Dan Bruton
Faculty Publications
A GeoWall is a passive stereoscopic projection system that can be used by students, teachers, and researchers for visualization of the structure and dynamics of three-dimensional systems and data. The type of system described here adequately provides 3-D visualization in natural color for large or small groups of viewers. The name “GeoWall” derives from its initial development to visualize data in the geosciences.1 An early GeoWall system was developed by Paul Morin at the electronic visualization laboratory at the University of Minnesota and was applied in an introductory geology course in spring of 2001. Since that time, several stereoscopic media, …
Radiation-Induced Current In Quantum Wires With Side-Coupled Nanorings, Yuriy V. Pershin Dr, Carlo Piermarocchi
Radiation-Induced Current In Quantum Wires With Side-Coupled Nanorings, Yuriy V. Pershin Dr, Carlo Piermarocchi
Faculty Publications
Photocurrent generation is studied in a system composed of a quantum wire with side-coupled quantum rings. The current generation results from the interplay of the particular geometry of the system and the use of circularly polarized radiation. We study the energy-momentum conservation for optical transitions involving electrons moving forward and backwards in the wire. Due to the lack of time-reversal symmetry in the radiation, the optical transitions depend on the direction of motion of the electrons, leading to a current at zero bias voltage. The photocurrent increases with the number of rings within a wide range of physical parameters. A …
Neutron Interferometric Method To Provide Improved Constraints On Non-Newtonian Gravity At The Nanometer Scale, Geoffrey L. Greene, Vladimir Gudkov
Neutron Interferometric Method To Provide Improved Constraints On Non-Newtonian Gravity At The Nanometer Scale, Geoffrey L. Greene, Vladimir Gudkov
Faculty Publications
In recent years, an energetic experimental program has set quite stringent limits on a possible “non-1/r2” dependence on gravity at short length scales. This effort has been largely driven by the predictions of theories based on compactification of extra spatial dimensions. It is characteristic of many such theories that the strength and length scales of such anomalous gravity are not clearly determined from first principles. As a result, it is productive to extend the current limits the range and strength of such hypothetical interactions. As a heavy, neutral, and (almost) stable particle, the neutron provides an ideal probe …
Theory Of Cavity-Polariton Self-Trapping And Optical Strain In Polymer Chains, M. V. Katkov, Yuriy V. Pershin Dr, C. Piermarocchi
Theory Of Cavity-Polariton Self-Trapping And Optical Strain In Polymer Chains, M. V. Katkov, Yuriy V. Pershin Dr, C. Piermarocchi
Faculty Publications
We consider a semiconductor polymer chain coupled to a single electromagnetic mode in a cavity. The excitations of the chain have a mixed exciton-photon character and are described as polaritons. Polaritons are coupled to the lattice by the deformation potential interaction and can propagate in the chain. We find that the presence of optical excitation in the polymer induces strain on the lattice. We use a BCS variational wave function to calculate the chemical potential of the polaritons as a function of their density. We analyze first the case of a short chain with only two unit cells in order …
Positive Current Correlations Associated With Super-Poissonian Shot Noise, Yuanzhen Chen, Richard A. Webb
Positive Current Correlations Associated With Super-Poissonian Shot Noise, Yuanzhen Chen, Richard A. Webb
Faculty Publications
We report on shot noise cross spectrum measurements in a beam splitter configuration. Electrons tunneling through potential barriers are incident on a beam splitter and scattered into two separate channels. Such a partition process introduces correlations between the fluctuations of the two currents. Our work has confirmed that the generally expected negative correlations resulted from sub-Poissonian electron sources. More interestingly, positive cross correlations associated with barriers exhibiting super-Poissonian shot noise have also been observed. We have found that both positive and negative correlations can be related to the noise properties of the electron source.
General Classification And Analysis Of Neutron Β-Decay Experiments, Vladimir Gudkov, G. L. Greene, J. R. Calarco
General Classification And Analysis Of Neutron Β-Decay Experiments, Vladimir Gudkov, G. L. Greene, J. R. Calarco
Faculty Publications
A general analysis of the sensitivities of neutron β-decay experiments to manifestations of possible interaction beyond the standard model is carried out. In a consistent fashion, we take into account all known radiative and recoil corrections arising in the standard model. This provides a description of angular correlations in neutron decay in terms of one parameter, which is accurate to the level of ~10-5. Based on this general expression, we present an analysis of the sensitivities to new physics for selected neutron decay experiments. We emphasize that the usual parametrization of experiments in terms of the tree-level coefficients …
Full Shot Noise In Mesoscopic Tunnel Barriers, Yuanzhen Chen, Richard A. Webb
Full Shot Noise In Mesoscopic Tunnel Barriers, Yuanzhen Chen, Richard A. Webb
Faculty Publications
We report shot noise measurements performed in mesoscopic tunnel barriers fabricated in a GaAs∕AlGaAs heterostructure. Two sets of tunnel barriers of different size are used in the study. All large size samples and some of the small size samples show a nonlinear dependence of shot noise on tunneling current due to localized states inside the barriers. Both suppression and enhancement of shot noise have been observed. Some small size barriers, however, exhibit the shot noise behavior of an ideal tunnel barrier over a wide range of barrier transmission coefficients, tunneling currents, and bias voltages.
Laser-Controlled Local Magnetic Field With Semiconductor Quantum Rings, Yuriy V. Pershin Dr, Carlo Piermarocchi
Laser-Controlled Local Magnetic Field With Semiconductor Quantum Rings, Yuriy V. Pershin Dr, Carlo Piermarocchi
Faculty Publications
We analyze theoretically the dynamics of N electrons localized in a narrow semiconductor quantum ring under a train of phase-locked infrared laser pulses. The pulse sequence is designed to control the total angular momentum of the electrons. The quantum ring can be put in states characterized by strong currents. The local magnetic field created by these currents can be used for a selective quantum control of single spins in semiconductor systems. The current generation in quantum rings with finite width is also studied.
Spin-Photovoltaic Effect In Quantum Wires Due To Intersubband Transitions, Arkady Fedorov, Yuriy V. Pershin Dr, Carlo Piermarocchi
Spin-Photovoltaic Effect In Quantum Wires Due To Intersubband Transitions, Arkady Fedorov, Yuriy V. Pershin Dr, Carlo Piermarocchi
Faculty Publications
We consider the current induced in a quantum wire by external electromagnetic radiation. The photocurrent is caused by the interplay of spin-orbit interaction (Rashba and Dresselhaus terms) and an external in-plane magnetic field. We calculate this current using a Wigner functions approach, taking into account radiation-induced transitions between transverse subbands. The magnitude and the direction of the current depends on the Dresselhaus and Rashba constants, strength of magnetic field, radiation frequency, and intensity. The current can be controlled by changing some of these parameters.
Photovoltaic Effect In Bent Quantum Wires In The Ballistic Transport Regime, Yuriy V. Pershin Dr, Carlo Piermarocchi
Photovoltaic Effect In Bent Quantum Wires In The Ballistic Transport Regime, Yuriy V. Pershin Dr, Carlo Piermarocchi
Faculty Publications
A scheme for the generation of a photocurrent in bent quantum wires is proposed. We calculate the current using a generalized Landauer-Büttiker approach that takes into account the electromagnetic radiation. For circularly polarized light, it is demonstrated that the curvature in the bent wire induces an asymmetry in the scattering coefficients for left and right moving electrons. This asymmetry results in a current at zero bias voltage. The effect is due to the geometry of the wire which transforms the photon angular momentum into translational motion for the electrons. Possible experimental realizations of this scheme are discussed.
Persistent And Radiation-Induced Currents In Distorted Quantum Rings, Yuriy V. Pershin Dr, Carlo Piermarocchi
Persistent And Radiation-Induced Currents In Distorted Quantum Rings, Yuriy V. Pershin Dr, Carlo Piermarocchi
Faculty Publications
Persistent and radiation-induced currents in distorted narrow quantum rings are theoretically investigated. We show that ring distorsions can be described using a geometrical potential term. We analyze the effect of this term on the current induced by a magnetic flux (persistent current) and by a polarized coherent electromagnetic field (radiation-induced current). The strongest effects in persistent currents are observed for distorted rings with a small number of electrons. The distortion smoothes the current oscillations as a function of the magnetic flux and changes the temperature dependence of the current amplitude. For radiation-induced currents, the distortion induces an ac component in …
Temperature-Dependent Asymmetry Of The Nonlocal Spin-Injection Resistance: Evidence For Spin Nonconserving Interface Scattering, Samir Garzon, Igor Žutić, Richard A. Webb
Temperature-Dependent Asymmetry Of The Nonlocal Spin-Injection Resistance: Evidence For Spin Nonconserving Interface Scattering, Samir Garzon, Igor Žutić, Richard A. Webb
Faculty Publications
We report nonlocal spin injection and detection experiments on mesoscopic Co-Al2O3-Cu spin valves. We have observed a temperature-dependent asymmetry in the nonlocal resistance between parallel and antiparallel configurations of the magnetic injector and detector. This strongly supports the existence of a nonequilibrium resistance that depends on the relative orientation of the detector magnetization and the nonequilibrium magnetization in the normal metal providing evidence for increasing interface spin scattering with temperature.
Long-Lived Spin Coherence States In Semiconductor Heterostructures, Yuriy V. Pershin Dr
Long-Lived Spin Coherence States In Semiconductor Heterostructures, Yuriy V. Pershin Dr
Faculty Publications
We study evolution of electron spin coherence having nonhomogeneous direction of spin polarization vector in semiconductor heterostructures. It is found that the electron spin relaxation time due to the D’yakonov- Perel’ relaxation mechanism essentially depends on the initial spin polarization distribution. This effect has its origin in the coherent spin precession of electrons diffusing in the same direction. We predict a long spin relaxation time of a novel structure: a spin coherence standing wave and discuss its experimental realization.
Mohanty And Webb Reply, P. Mohanty, Richard A. Webb
Mohanty And Webb Reply, P. Mohanty, Richard A. Webb
Faculty Publications
A Reply to the Comment by V. I. Fal'ko et al.
Polarization Of Nuclear Spins From The Conductance Of Quantum Wires, James A. Nesteroff, Yuriy V. Pershin Dr, Vladimir Privman
Polarization Of Nuclear Spins From The Conductance Of Quantum Wires, James A. Nesteroff, Yuriy V. Pershin Dr, Vladimir Privman
Faculty Publications
We devise an approach to measure the polarization of nuclear spins via conductance measurements. Specifically, we study the combined effect of external magnetic field, nuclear spin polarization, and Rashba spin-orbit interaction on the conductance of a quantum wire. Nonequilibrium nuclear spin polarization affects the electron energy spectrum making it time dependent. Changes in the extremal points of the spectrum result in time dependence of the conductance. The conductance oscillation pattern can be used to obtain information about the amplitude of the nuclear spin polarization and extract the characteristic time scales of the nuclear spin subsystem.
New Enhanced Tunneling In Nuclear Processes, Boris Ivlev, Vladimir Gudkov
New Enhanced Tunneling In Nuclear Processes, Boris Ivlev, Vladimir Gudkov
Faculty Publications
The small sub-barrier tunneling probability of nuclear processes can be dramatically enhanced by collision with incident charged particles. Semiclassical methods of theory of complex trajectories have been applied to nuclear tunneling, and conditions for the effects have been obtained. We demonstrate the enhancement of αparticle decay by incident proton with energy of about 0.25 MeV. We show that the general features of this process are common for other sub-barrier nuclear processes and can be applied to nuclear fission.
Effect Of Spin-Orbit Interaction And In-Plane Magnetic Field On The Conductance Of A Quasi-One-Dimensional System, Yuriy V. Pershin Dr, James A. Nesteroff, Vladimir Privman
Effect Of Spin-Orbit Interaction And In-Plane Magnetic Field On The Conductance Of A Quasi-One-Dimensional System, Yuriy V. Pershin Dr, James A. Nesteroff, Vladimir Privman
Faculty Publications
We study the effect of spin-orbit interaction and in-plane effective magnetic field on the conductance of a quasi-one-dimensional ballistic electron system. The effective magnetic field includes the externally applied field, as well as the field due to polarized nuclear spins. The interplay of the spin-orbit interaction with effective magnetic field significantly modifies the band structure, producing additional subband extrema and energy gaps, introducing the dependence of the subband energies on the field direction. We generalize the Landauer formula at finite temperatures to incorporate these special features of the dispersion relation. The obtained formula describes the conductance of a ballistic conductor …