Coupled Electromagnetic Circuits and Their Connection to Quantum Mechanical Resonance Interactions and Biorhythms

The existence of specific biorhythms and the role of geomagnetic and/or solar magnetic activities are well-established by appropriate correlations in chronobiology. From a physical viewpoint, there are two different accesses to biorhythms to set up connections to molecular processes: quantum mechanical perturbation theoretical methods and their resonance dominators to characterize specific interactions between constituents. These methods permit the treatment of molecular processes by circuits with characteristic resonances and “beat-frequencies”, which result from primarily fast physical processes. As examples, the tunneling processes between DNA base pairs (H bonds), the ATP decomposition and the irradiation of tumor cells are accounted for.

Electro-mechanical coupling properties of band gaps in an with periodically attached “spring-mass” resonators

The model of a locally resonant (LR) epoxy/PZT-4 phononic crystal (PC)nanobeam with “spring-mass” resonators periodically attached to epoxy is proposed. The corresponding band structures are calculated by coupling Euler beam theory, nonlocal piezoelectricity theory and plane wave expansion (PWE) method. Three complete band gaps with the widest total width less than 10GHz can be formed in the proposed nanobeam by comprehensively comparing the band structures of three kinds of LR PC nanobeams with resonators attached or not. Furthermore, influencing rules of the coupling fields between electricity and mechanics,“spring-mass” resonator, nonlocal effect and different geometric parameters on the first three band gaps are discussed and summarized. All the investigations are expected to be applied to realize the active control of vibration in the region of ultrahigh frequency.

Review of cavity optomechanical cooling

Quantum manipulation of macroscopic mechanical systems is of great interest in both fundamental physics and ap- plications ranging from high-precision metrology to quantum information processing. For these purposes, a crucial step is to cool the mechanical system to its quantum ground state. In this review, we focus on the cavity optomechanical cooling, which exploits the cavity enhanced interaction between optical field and mechanical motion to reduce the thermal noise. Recent remarkable theoretical and experimental efforts in this field have taken a major step forward in preparing the mo- tional quantum ground state of mesoscopic mechanical systems. This review first describes the quantum theory of cavity optomechanical cooling, including quantum noise approach and covariance approach; then, the up-to-date experimental progresses are introduced. Finally, new cooling approaches are discussed along the directions of cooling in the strong coupling regime and cooling beyond the resolved sideband limit.

Research on Resonance Mechanism of Arc-ultrasonic

As a transmission medium, welding arc can be modulated to emit ultrasonic energy by exerting high-frequency electric current. The frequency of exciting electric current has notable influence on the signals recorded by the sensors and the metallographic structures of the welds. The resonance phenomenon of arc-uitrasonic has been found in the experiment. Both the resonance mechanism and the distribution of resonance frequency are discussed by the bui|t vibration equation.

Two-mode squeezed state of nanomechanical resonators

In this paper, we introduce a flexible model for the control and measurement of NAMRs （nanomechanical resonators）. We obtain the free Hamiltonian of the dcSQUID （direct current superconducting quantum interference device） and the interaction Hamiltonian between these two NAMRs and the dc-SQUID by introducing the annihilation and creation operators under the rotating wave approximation. We can treat the mode of the dc-SQUID as a classical field. In the Heisenberg picture, the generation of two-mode squeezed states of two nanomechanical resonators is shown by their collective coordinate and momentum operators.

Soliton molecules and asymmetric solitons of the extended Lax equation via velocity resonance

We investigate the techniques for velocity resonance and apply them to construct soliton molecules using two solitons of the extended Lax equation.What is more,each soliton molecule can be transformed into an asymmetric soliton by changing the parameterφ.In addition,the collision between soliton molecules(or asymmetric soliton)and several soliton solutions is observed.Finally,some related pictures are presented.

Resonance mechanism of flapping wing based on fluid structure interaction simulation

Certain insect species have been observed to exploit the resonance mechanism of their wings.In order to achieve resonance and optimize aerodynamic performance,the conventional approach is to set the flapping frequency of flexible wings based on the Traditional Structural Modal(TSM)analysis.However,there exists controversy among researchers regarding the relationship between frequency and aerodynamic performance.Recognizing that the structural response of wings can be influenced by the surrounding air vibrations,an analysis known as Acoustic Structure Interaction Modal(ASIM)is introduced to calculate the resonant frequency.In this study,Fluid Structure Interaction(FSI)simulations are employed to investigate the aerodynamic performance of flapping wings at modal frequencies derived from both TSM and ASIM analyses.The performance is evaluated for various mass ratios and frequency ratios,and the findings indicate that the deformation and changes in vortex structure exhibit similarities at mass ratios that yield the highest aerodynamic performance.Notably,the flapping frequency associated with the maximum time-averaged vertical force coefficient at each mass ratio closely aligns with the ASIM frequency,as does the frequency corresponding to maximum efficiency.Thus,the ASIM analysis can provide an effective means for predicting the optimal flapping frequency for flexible wings.Furthermore,it enables the prediction that flexible wings with varying mass ratios will exhibit similar deformation and vortex structure changes.This paper offers a fresh perspective on the ongoing debate concerning the resonance mechanism of Flexible Flapping Wings(FFWs)and proposes an effective methodology for predicting their aerodynamic performance.

Periodic Orbits in Rotating Second Degree and Order Gravity Fields

Periodic orbits in an arbitrary 2nd degree and order uniformly rotating gravity field are studied. We investigate the four equilibrium points in this gravity field. We see that close relation exists between the stability of these equilibria and the existence and stability of their nearby periodic orbits. We check the periodic orbits with non-zero periods. In our searching procedure for these periodic orbits, we remove the two unity eigenvalues from the state transition matrix to find a robust, non-singular linear map to solve for the periodic orbits. The algorithm converges well, especially for stable periodic orbits. Using the searching procedure, which is relatively automatic, we find five basic families of periodic orbits in the rotating second degree and order gravity field for planar motion, and discuss their existence and stability at different central body rotation rates.

Visualizing nonlinear resonance in nanomechanical systems via single-electron tunneling

Numerous reports have elucidated the importance of mechanical resonators comprising quantum-dot-embedded carbon nanotubes(CNTs)for studying the effects of single-electron transport.However,there is a need to investigate the single-electron transport that drives a large amplitude into a nonlinear regime.Herein,a CNT hybrid device has been investigated,which comprises a gate-defined quantum dot that is embedded into a mechanical resonator under strong actuation conditions.The Coulomb peak positions synchronously oscillate with the mechanical vibrations,enabling a single-electron Chopper*1 mode.Conversely,the vibration amplitude of the CNT versus its frequency can be directly visualized via detecting the time-averaged single-electron tunneling current.To understand this phenomenon,a general formula is derived for this time-averaged single-electron tunneling current,which agrees well with the experimental results.By using this visualization method,a variety of nonlinear motions of a CNT mechanical oscillator have been directly recorded,such as Duffing nonlinearity,parametric resonance,and double-,fractional-,mixed-frequency excitations.This approach opens up burgeoning opportunities for investigating and understanding the nonlinear motion of a nanomechanical system and its interactions with electron transport in quantum regimes.

Microscale Crystalline Rare-Earth Doped Resonators for Strain-Coupled Optomechanics

Rare-earth ion doped crystals for hybrid quantum technologies are an area of growing interest in the solid-state physics community. We have earlier theoretically proposed a hybrid scheme of a mechanical resonator which is fabricated out of a rare-earth doped mono-crystalline structure. The rare-earth ion dopants have absorption energies which are sensitive to crystal strain, and it is thus possible to couple the ions to the bending motion of the crystal cantilever. This type of resonator can be useful for either investigating the laws of quantum physics with material objects or for applications such as sensitive force-sensors. Here, we present the design and fabrication method based on focused-ion-beam etching techniques which we have successfully employed in order to create such microscale resonators, as well as the design of the environment which will allow studying the quantum behavior of the resonators.

Optical fiber-based magnetically-tuned graphene mechanical resonator

In this study,an optical fiber-based magnetically-tuned graphene mechanical resonator(GMR)is demonstrated by integrating superparamagnetic iron oxide nanoparticles on the graphene membrane.The resonance frequency shift is achieved by tuning the tension of the graphene membrane with a magnetic field.A resonance frequency tunability of 23 kHz using a 100 mT magnetic field is achieved.The device provides a new way to tune a GMR with a non-contact force.It could also be used for weak magnetic field detection in the future with further improvements in sensitivity.

Optomechanical sensing with on-chip microcavities

The coupling between optical and mechanical degrees of freedom has been of broad interest for a long time. However, it is only until recently, with the rapid development of optical mierocavity research, that we are able to manipulate and utilize this coupling process. When a high Q microeavity couples to a mechanical resonator, they can consolidate into an optomeehanieal system. Benefitting from the unique characteristics offered by optomeehanical coupling, this hybrid system has become a promising platform for ultrasensitive sensors to detect displacement, mass, force and acceleration. In this review, we introduce the basic physical concepts of cavity optomechanies, and describe some of the most typical experimental cavity optomechanical systems for sensing applications. Finally, we discuss the noise arising from various sources and show the potentiality of optomechanical sensing towards quantum-noise-limited detection.

Mechanical quality factor of high-overtone bulk acoustic resonator

Mechanical quality factor Qm is a key characteristic parameter of High-overtone bulk acoustic resonator（HBAR）. The effects of structure parameter（thickness） and perfor？mance parameters（characteristic impedance and mechanical attenuation factor） of substrate,piezoelectric film and electrode constituting HBAR on Qm are carried out. The relationships between Qm and these parameters are obtained by a lumped parameter equivalent circuit instead of distributed parameter equivalent circuit near the resonance frequency, and the an？alytical expressions oi Qm are given. The results show that Qm increases non-monotonically with the continuous increase of the substrate thickness for HBAR with certain piezoelectric film thickness, and it approaches to the substrate material mechanical quality factor as the substrate thickness is large. Qm decreases wavily with the continuous increase of the piezoelectric film thickness for HBAR with certain substrate thickness. Sapphire and YAG with low mechanical loss are appropriate as the substrate to get a larger Qm- The electrode loss must be considered since it can reduce Qm- Compared with Au electrode, A1 electrode with lower loss can obtain higher Qm when the appropriate electrode thickness is selected. In addition, Qm decreases with the increase of frequency. These results provide the theoretical basis for optimizing the parameters of HBAR and show that trade-oflFs between Qm and must be considered in the design because their changes are often inconsistent.

Soliton molecules for combined mKdV-type bilinear equation

Starting from the multi-soliton solutions obtained by the Hirota bilinear method,the soli ton molecule structures for the combined mKdV-type bilinear equation(Dt+∑n=1NαnDx2n+1)f*·f=0 are investigated using the velocity resonance mechanism.The two-soliton molecules of the mKdV-35 equation and the three-soliton molecules of the mKdV-357 equation are specifically demonstrated in this paper.With particular selections of the involved arbitrary parameters,especially the wave numbers,it is confirmed that,besides the usual multi-bright soliton molecules,the multi-dark soliton molecules and the mixed multibright-dark soliton molecules can also be obtained.In addition,we discuss the existence of the multi-soliton molecules for the combined mKdV-type bilinear equation with more higher order nonlinear terms and dispersions.The results demonstrate that when N≥4,the combined mKdVtype bilinear equation no longer admits soliton molecules comprising more than four solitons.

Self-excited oscillation of spinning solar sails utilizing solar radiation pressure

The present paper proposes a control method to excite spinning solar sail membranes for three-dimensional use.Using optical property switching,the input is given as the change in magnitude of the solar radiation pressure.The resonance point of this system varies with the vibration state due to its nonlinearity and the change in equilibrium state.To deal with this,a state feedback control law that automatically tracks the resonance point is developed in the present study.The proposed method enables decentralized control of the actuators on the sail,each of which determines the control input independently using only the information of vibration state.The proposed method is validated using numerical simulations.The results show that the nonlinear system behaves differently from the linear system,and the vibration grows using the decentralized control regardless of resonance point variation.

Ultra-wide tuning single channel filter based on one-dimensional photonic crystal with an air cavity

By inserting an air cavity into a one-dimensional photonic crystal of LiF/GaSb, a tunable filter covering the whole visible range is proposed. Following consideration of the dispersion of the materials, through modulating the thickness of the air cavity, we demonstrate that a single resonant peak can shift from 416.1 to 667.3 nm in the band gap at normal incidence by means of the transfer matrix method. The research also shows that the transmittance of the channel can be maximized when the number of periodic Li F/Ga Sb layers on one side of the air defect layer is equal to that of the other side. When adding a period to both sides respectively, the full width at half maximum of the defect mode is reduced by one order of magnitude. This structure will provide a promising approach to fabricate practical tunable filters in the visible region with ultra-wide tuning range.