Amorphous sputter-deposited NiTi thin films were subjected to pulsed, melt-mediated laser crystallization techniques to engineer their microstructure. The effects of laser processing of pre-heated films are examined. ...
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Amorphous sputter-deposited NiTi thin films were subjected to pulsed, melt-mediated laser crystallization techniques to engineer their microstructure. The effects of laser processing of pre-heated films are examined. Laser processing of films at an elevated temperature has a significant effect on the rate with which solidification occurs and therefore may be used as an added parameter to control the resulting microstructure. It is seen that the temperature at which processing is carried out has significant implications for the resulting phase and microstructure, and therefore mechanical properties. Furthermore, the microstructural effects of varying incident laser energy density are examined via atomic force microscopy (AFM), scanning electron microscopy (SEM) and x-ray diffraction (XRD), and mechanical/shape memory properties are characterized via nanoindentation.
Within the framework of the Drude dispersive model, we predict an unusual nonmonotonic temperature dependence of the Casimir force for thin metal films. For certain conditions, this force decreases with temperature du...
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Within the framework of the Drude dispersive model, we predict an unusual nonmonotonic temperature dependence of the Casimir force for thin metal films. For certain conditions, this force decreases with temperature due to the decrease of the metallic conductivity, whereas the force increases at high temperatures due to the increase of the thermal radiation pressure. We consider the attraction of a film to: either (i) a bulk ideal metal with a planar boundary, or (ii) a bulk metal sphere (lens). The experimental observation of the predicted decreasing temperature dependence of the Casimir force can put an end to the long-standing discussion on the role of the electron relaxation in the Casimir effect.
作者：
Neill LambertFranco NoriAdvanced Science Institute
The Institute of Physical and Chemical Research (RIKEN) Saitama 351-0198 Japan Department of Physics
Center for Theoretical Physics Applied Physics Program Center for the Study of Complex Systems The University of Michigan Ann Arbor Michigan 48109-1040 USA
We consider a nanomechanical resonator coupled to a double quantum dot. We demonstrate how the finite-frequency current-noise spectrum through the double quantum dot can be used to distinguish classical and quantum be...
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We consider a nanomechanical resonator coupled to a double quantum dot. We demonstrate how the finite-frequency current-noise spectrum through the double quantum dot can be used to distinguish classical and quantum behavior in the nearby nanoelectromechanical resonator. We also show how the full-frequency current-noise spectrum gives important information on the combined double quantum dot-resonator energy spectrum. Finally, we point out regimes where the quantum state of the resonator becomes squeezed and also examine the cross-correlated electron-phonon current noise.
We describe the interaction between an electromagnetic field and a long Josephson junction driven by a dc current. We calculate the amplitudes of emission and absorption of light via the creation and annihilation of q...
We describe the interaction between an electromagnetic field and a long Josephson junction driven by a dc current. We calculate the amplitudes of emission and absorption of light via the creation and annihilation of quantized Josephson plasma waves (JPWs). Both the energies of JPW quanta and the amplitudes of light absorption and emission strongly depend on the junction’s length and can be tuned by an applied dc current. Moreover, photon-assisted macroscopic quantum tunneling in long Josephson junctions shows resonances when the frequency of the outside radiation coincides with the current-driven eigenfrequencies of the quantized JPWs.
A 2-D nonlinear time domain computational model of sonic boom propagation has been modified to incorporate the effects of atmospheric turbulence. This model, based on the Nonlinear Progressive wave Equation (NPE) of M...
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Density functional perturbation theory calculations have been utilized to characterize the carrier density dependent phonon dispersion of InSb. Similar to prior theoretical studies of Si, these calculations predict th...
Density functional perturbation theory calculations have been utilized to characterize the carrier density dependent phonon dispersion of InSb. Similar to prior theoretical studies of Si, these calculations predict that a shear instability develops in the crystal at a carrier density of 3.7% of the valence electron density and the entire transverse acoustic phonon branch becomes unstable over a narrow carrier density range of roughly 1%. Unlike calculations for Si, the shear instability appears first at the X point, rather than the L point. We utilize these calculations to interpret recent ultrafast x-ray diffraction measurements of laser-induced disordering in InSb and find that the time scale and laser fluence dependence of the measured disordering dynamics are consistent with these theoretical predictions. The calculations, however, do not reproduce the experimental anisotropy in the root-mean-square displacement.
It is evident from a wide range of experimental findings that ion channel gating is inherently stochastic. The issue of “memory effects” (diffusional retardation due to local changes in water viscosity) in ionic flo...
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It is evident from a wide range of experimental findings that ion channel gating is inherently stochastic. The issue of “memory effects” (diffusional retardation due to local changes in water viscosity) in ionic flow has been recently addressed using Brownian dynamics simulations. The results presented indicate such memory effects are negligible, unless the diffusional barrier is much higher than that of free solute. In this paper using differential stochastic methods we conclude that the Markovian property of exponential dwell times gives rise to a high barrier, resulting in diffusional memory effects that cannot be ignored in determining ionic flow through channels. We have addressed this question using a generalized Langevin equation that contains a combination of Markovian and non-Markovian processes with different time scales. This approach afforded the development of an algorithm that describes an oscillatory ionic diffusional sequence. The resulting oscillatory function behavior, with exponential decay, was obtained at the weak non-Markovian limit with two distinct time scales corresponding to the processes of ionic diffusion and drift. This will be analyzed further in future studies using molecular dynamics simulations. We propose that the rise of time scales and memory effects is related to differences of shear viscosity in the cytoplasm and extracellular matrix.
We consider the propagation of a classical electromagnetic wave through a transmission line, formed by identical superconducting charge qubits inside a superconducting resonator. Since the qubits can be in a coherent ...
We consider the propagation of a classical electromagnetic wave through a transmission line, formed by identical superconducting charge qubits inside a superconducting resonator. Since the qubits can be in a coherent superposition of quantum states, we show that such a system demonstrates interesting effects, such as a “breathing” photonic crystal with an oscillating band gap and a “quantum Archimedean screw” that transports, at an arbitrary controlled velocity, Josephson plasma waves through a transmission line. The key ingredient of these effects is that the optical properties of the Josephson transmission line are controlled by the quantum coherent state of the qubits.
We studied the quantum dynamics of ferromagnetic domain walls (topological kink-type solitons) in one-dimensional ferromagnetic spin chains. We show that the tunneling probability does not depend on the number of spin...
We studied the quantum dynamics of ferromagnetic domain walls (topological kink-type solitons) in one-dimensional ferromagnetic spin chains. We show that the tunneling probability does not depend on the number of spins in a domain wall; thus, this probability can be large even for a domain wall containing a large number of spins. We also predict that there is a strong interplay between the tunneling of a wall from one lattice site to another (tunneling of the kink coordinate) and the tunneling of the kink topological charge (so-called chirality). Both of these elementary processes are suppressed for kinks in one-dimensional ferromagnets with half-integer spin. The dispersion law (i.e., the domain wall energy versus momentum) is essentially different for chains with either integer or half-integer spins. The predicted quantum effects could be observed for mesoscopic magnetic structures, e.g., chains of magnetic clusters, large-spin molecules, or nanosize magnetic dots.
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