We propose a universal, on-chip quantum transducer based on surface acoustic waves in piezoactive materials. Because of the intrinsic piezoelectric (and/or magnetostrictive) properties of the material, our approach provides a universal platform capable of coherently linking a broad array of qubits, including quantum dots, trapped ions, nitrogen-vacancy centers, or superconducting qubits. The quantized modes of surface acoustic waves lie in the gigahertz range and can be strongly confined close to the surface in phononic cavities and guided in acoustic waveguides. We show that this type of surface acoustic excitation can be utilized efficiently as a quantum bus, serving as an on-chip, mechanical cavity-QED equivalent of microwave photons and enabling long-range coupling of a wide range of qubits.

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Universal Quantum Transducers based on Surface Acoustic Waves

Shear waves propagating along the imperfectly bonded interface of a magnetoelectric composite consisting of Piezoelectric (PE) and Piezomagnetic (PM) phases are considered. An exact dispersion relation is obtained. It is found that the interfacial imperfection strongly affects the velocity of interfacial shear waves. The existence condition of the interfacial shear waves is derived. In particular, for certain combined magnetoelectric composites, interfacial shear waves do no exist for perfect interface and exist only for imperfect interface. Moreover, the corresponding waves are dispersive, and the range of the phase velocity is derived, lying between the smaller of the Bleustein-Gulyaev waves of two PE and PM materials and the interfacial waves for the perfect bonding. These findings are useful for PE/PM composites in the microwave technology.

Interfacial shear horizontal (SH) waves propagating in a two-phase piezoelectric/piezomagnetic structure with an imperfect interface

Liouville-Green approximation: An analytical approach to study the elastic waves vibrations in composite structure of piezo material

The paper analyzes the reflection and transmission of plane waves at an imperfect interface between piezoelectric (PE) and piezomagnetic (PM) media. The materials are assumed to be transversely isotropic. The linear spring model is used to describe the imperfection of bonding behavior at the interface. According to this model, the properties of the interface can be characterized by the normal and tangential interfacial stiffnesses. Numerial examples are performed for BaTiO3/CoFe2O4 material combination. Four cases, a perfect, slip, normal weak bonding and unbonding interfaces for the coupled quasi-pressure (QP) wave incidence from BaTiO3 medium are compared in detail. Numerical results of the reflection and transmission coefficients (RTCs) varying with incident angle for different interfacial stiffnesses are presented. Results show that the transmitted QP/reflected QSV waves are the strongest in the perfect/unbonded cases, respectively. The scattered waves in the slip and normal weak bonding cases are between those of the perfect and unbonded cases generally. Critial angles have noticeable effect on the RTCs and energy coefficients for the coupled scattered waves of the perfect and slip cases but have a little/no effect on those of the normal weak bonding/unbonded cases. It is found that the sum of the energy carried by the transmitted/reflected QP and QSV waves is less than unit for the imperfect bonding between BaTiO3/CoFe2O4 solids. These results may provide some useful reference datum for the imperfection measurment at the PE and PM interface.

Reflection and transmission of plane waves at an imperfectly bonded interface between piezoelectric and piezomagnetic media

The propagation of shear horizontal waves in laminated piezomagnetic/piezoelectric plates was investigated using the ordinary differential equation and stiffness matrix methods. Commonly used materials, namely barium titanate as piezoelectric ‘B’ and cobalt ferrite as piezomagnetic ‘F’, were retained for illustration. The dispersion curves of the first five modes were shown for different sequences F/F, B/B, and F/B. The effects of thickness ratio on phase and group velocities as well as the influence on the magneto-electromechanical coupling factor of the first mode were investigated. Large magneto-electromechanical coupling factors could be achieved by an appropriate adjustment of the thickness ratio. The present investigation is of practical interest for developing new layered composites made of smart piezoelectric and piezomagnetic devices for engineering applications.

Xiao-Fang Zhao

Papers

Love waves in layered piezoelectric/piezomagnetic structures