Magnetothermoelectric response at a superfluid-Mott-insulator transition

We investigate the finite temperature magnetothermoelectric response in the vicinity of a superfluid-Mott-insulator quantum phase transition. We focus on the particle-hole symmetric transitions of the Bose-Hubbard model, and combine Lorentz invariance arguments with quantum Boltzmann calculations. By means of an epsilon expansion, we find that a nonvanishing thermoelectric tensor and a finite thermal transport coefficient are supported in this quantum critical regime. We comment on the singular Nernst effect in this problem.     

流体-镀层基底界面波的传播特性

理论分析了脉冲激光激发的流体-分层固体结构声场,在此基础上数值计算了流体-慢层快底固体和流体-快层慢底固体结构液-固界面Scholte波的频散特性与瞬态响应.数值结果显示,对于流体-慢层快底结构,Scholte界面波呈现出正常频散特性;而对于流体-快层慢底结构,Scholte波在较小的频厚积范围呈反常频散特性.理论瞬态信号也显示了同样的特性.采用脉冲激光激励,用水听器接收的方式进行了Scholte界面波的实验测量.实验测量和分析结果与理论结果有很好的一致性.此工作可为水浸检测条件下镀层与薄膜材料参数的超声无损表征、海底沉积物参数反演等应用提供理论基础.     

Generation of electrohydrodynamic waves at the liquid-vacuum interface

The linear electrodynamic problem of the stability of a viscous liquid surface at the liquid-air interface is studied in view of the surface charge kinetics. The electric field critical intensities which break the stability of the plane interface are determined. Conditions for generating sustained waves at the interface are found.     

Surface acoustic waves at the vacuum-thermoviscoelastic solid interface

The present investigation concerns the propagation of surface waves at the vacuum-solid interface of a solid which is isotropic and thermoviscoelastic, i.e., for which the effects of heat conductivity need to be taken into account. Calculations show that, in addition to the Rayleigh wave, a thermal surface wave propagates that couples both the thermal and the elasticity effects. This latter wave is interpreted in terms of evanescent plane waves. The displacement field associated with this wave is calculated and interpreted. Some experimental results are also presented.     

Surface electromagnetic waves at a superconductor-dielectric interface

This paper reports on the results of investigating the frequency dependence, the structure, and the polarization-and energy-related characteristics of surface electromagnetic waves propagating along a superconductor-dielectric interface. An expression for the complex permittivity of a superconductor is derived in the approximation of a two-component plasma containing “normal” and “superconducting” electrons. Basic relations are obtained in the general case at temperatures T≤T _c (where T _c is the critical temperature) and in the limiting case at T?T _c, when the contribution from normal electrons to the permittivity of the superconductor can be disregarded.     

Surface acoustic waves at a free-metallized interface

Light scattering was used to study surface acoustic waves at a free-metalized interface on piezoelectric lithium niobate. An interaction region of several acoustic wavelengths was observed in which a reflected surface wave and a continuous spectrum of bulk waves are generated.     

Transient radiation of acoustic waves at the atmosphere-earth interface

Using the contour integration method, we solved the problem on the transient radiation of acoustic waves by a mass-production source which moves uniformly in a gas in the direction normal to the interface of homogeneous gaseous and elastic half-spaces and vanishes at the moment of the solid surface contact. Asymptotic formulas are derived for the transient radiation field which are valid at the fronts of spherical and lateral waves. An exact analytical expression is obtained for the transient radiation field at observation points in the source trajectory. The total internal reflection effects in the transient radiation of sound are analyzed. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 4, pp. 420–431, April, 1997.     

Transition radiation of seismic waves at the atmosphere-earth interface

The method of contour integration is used for solving the problem of transition radiation of elastic waves by a mass source, which travels uniformly in a gas normal to the interface between homogeneous gaseous and elastic halfspaces and disappears at the time it touches the solid surface. We have obtained asymptotic formulas for the field of transition radiation, which hold true near the fronts of longitudinal and transverse spherical waves and a conical wave. An exact analytical expression for the field of transition radiation has been obtained for the observation points located on the source trajectory extension in a solid. The influence of interaction between longitudinal and transverse waves, which occurs on the surface of elastic medium, on the space distribution of the field of transition radiation is analyzed. Radiophysical Research Institute, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 40, No. 10, pp. 1210–1223, October, 1997.     

Diffraction of SH waves at a mixed interface

Summary We study the diffraction of SH-type elastic waves propagating along the plane interface between two dissimilar elastic half-spaces. It is assumed that the contact between the half-spaces is perfect except for a part of semi-infinite extension where the contact is loosely coupled. We use the Wiener-Hopf technique to obtain the diffracted field in a closed form.     

Quantum control of donor electrons at the Si-SiO2 interface

Prospects for the quantum control of electrons in the silicon quantum computer architecture are considered theoretically. In particular, we investigate the feasibility of shuttling donor-bound electrons between the impurity in the bulk and the Si-SiO2 interface by tuning an external electric field. We calculate the shuttling time to range from subpicoseconds to nanoseconds depending on the distance (approximately 10-50 nm) of the donor from the interface. Our results establish that quantum control in such nanostructure architectures could, in principle, be achieved.     

Surface electromagnetic waves at the interface between two dielectric superlattices

The electrodynamic properties of the interface between two periodic dielectric superlattices are studied. It is shown that the interface may serve as a guide for an electromagnetic wave whose field decays exponentially on both sides of the plane of the interface. The field and power flux distributions, as well as the frequency dependence of the field penetration depth, are studied.     

Transformation of detonation waves at the interface between bubble media

The passage of detonation waves through the interface between bubble media is studied experimentally. Data are obtained for the structure, velocity, and pressure of an incident detonation wave and a wave transmitted through the interface.     

声波在水-含气沉积物界面的反射

含气泡海洋沉积物的声学特性是海底探测的重要问题。为了研究气泡存在对水-含气沉积物界面声反射系数的影响,本文基于气泡振动修正的Biot波动方程推导了气泡存在修正的Biot弹性模量,并结合水-沉积物界面的“开孔”边界条件推导了声波从水入射到水-含气沉积物界面的反射系数。数值分析表明气泡的振动导致反射系数呈现显著的频率特性。在气泡共振频率附近,由于气泡的共振引发的强散射和强衰减,使得反射系数很大,无论以何种角度入射,声波都很难进入含气泡的沉积物。本文研究结果表明,气泡半径、含量、声波频率以及入射角度都是影响水-含气沉积物界面反射系数的主要因素。     

Pseudo interface waves observed at the fluid/porous-medium interface. A comparison of two methods

At the fluid/porous-medium interface the pseudo-Rayleigh (pR) and pseudo-Stoneley (pSt) waves exist. The relation with the corresponding poles in the slowness plane is not unambiguous, depending on the choice of branch cuts. For a point-force excitation, the far-field Green's functions are computed using vertical branch cuts (method I) implying that the pR- and pSt-poles obey the radiation condition. Then, a separate pseudo interface wave is entirely captured by the corresponding pole residue because the loop integral along a branch cut contributes to a body wave only. When hyperbolic branch cuts are used (method II) the poles lie on the "principal" Riemann sheet. Then, also the loop integrals necessarily contribute to the pR-wave because the pR-pole is different from that in method I. They do not contribute to the pSt-wave when the pSt-pole lies on the principal Riemann sheet because the pole is identical to that in method I. When the pSt-pole has migrated to another Riemann sheet, however, the pSt-wave is fully captured by the loop integrals. In conclusion, the phase velocity and attenuation of a separate pseudo interface wave can be computed from the pole location in method I, but should be extracted from the full response in method II.