Mechanical Oscillator Research Articles

Ultracoherent Nanomechanical Resonators Based on Density Phononic Crystal Engineering

Micromechanical and nanomechanical systems with exceptionally low dissipation rates are enabling the next-generation technologies of ultrasensitive detectors and quantum information systems. New techniques and methods for lowering the dissipation rate have in recent years been discovered and allowed for the engineering of mechanical oscillators with phononic modes that are extremely well isolated from the environment and thus possess quality factors close to and beyond 1×109. A powerful strategy for isolating and controlling a single phononic mode is based on phononic crystal engineering. Here we propose a new method for phononic crystal engineering of nanomechanical oscillators that is based on a periodic variation of the material density. To circumvent the introduction of additional bending losses resulting from the variation of material density, the added mass constitutes an array of nanopillars in which the losses will be diluted. Using this novel technique for phononic crystal engineering, we design and fabricate corrugated mechanical oscillators with quality factors approaching 1×109 in a room temperature environment. The flexibility space of these new phononic crystals is large and further advancement can be attained through optimized phononic crystal patterning and strain engineering via topology optimization. This will allow for the engineering of mechanical membranes with quality factors beyond 1×109 at room temperature. Such extremely low mechanical dissipation rates will enable the development of radically new technologies such as quantum-limited atomic force microscopy at room temperature, ultrasensitive detectors of dark matter, spontaneous waveform collapses, gravity, and high-efficiency quantum information transducers. Published by the American Physical Society 2024

Control of Vibratory Feeder Device Mechanical Frequency Using the Modification of the Sinusoidal Supply Voltage Signal

In the industrial and sales processes, dosing systems of various constructions, whose operation is based on mechanical vibrations (vibratory feeders), are very often used. These systems face many problems, such as resonant frequency, flow instability of dosed product, instability of mechanical vibration amplitude, etc., because most of them are based on controlling the frequency of the electrical signal of the supply voltage. All these factors negatively affect the durability and reliability of the vibratory feeder systems. During this research, an automatic control system for vibratory feeder was created, whose control process is based on the modification of the sinusoidal signal (partially changing the signal area). In addition, such a way of controlling the vibratory feeder is not discussed in the literature. As the research conducted in this paper has shown, while using sinusoidal signal modification it was possible to achieve a stable flow rate of bulk production (the flow rate varied from 0 to 100 g/s when the frequency of mechanical vibrations changed from 1 to 50 Hz) and a stable amplitude of mechanical oscillations was achieved and equal to 1.5 mm. The control system is based on the microcontroller PIC24FV32KA302 for which the special software was developed. The thyristor BTA16 used for voltage modification of the sinusoidal signal made it possible to ensure the reliable control of the sinusoidal voltage modification process.

Molecular optomechanics in the anharmonic regime: from nonclassical mechanical states to mechanical lasing

Cavity optomechanics aims to establish optical control over vibrations of nanoscale mechanical systems, to heat, cool or to drive them toward coherent, or nonclassical states. This field was recently extended to encompass molecular optomechanics: the dynamics of THz molecular vibrations coupled to the optical fields of lossy cavities via Raman transitions. The molecular platform should prove suitable for demonstrating more sophisticated optomechanical effects, including engineering of nonclassical mechanical states, or inducing coherent molecular vibrations. We propose two schemes for implementing these effects, exploiting the strong intrinsic anharmonicities of molecular vibrations. First, to prepare a nonclassical mechanical state, we propose an incoherent analogue of the mechanical blockade, in which the molecular anharmonicity and optical response of hybrid cavities isolate the two lowest-energy vibrational states. Secondly, we show that for a strongly driven optomechanical system, the anharmonicity can suppress the mechanical amplification, shifting and reshaping the onset of coherent mechanical oscillations. Our estimates indicate that both effects should be within reach of existing platforms for Surface Enhanced Raman Scattering.

Preparation of Distant Quantum Entanglement and One‐way Quantum Steering in Hybrid Cavity‐Magnonics‐and‐Cavity‐Optomechanical Systems

AbstractA hybrid system that combines cavity magnonics and cavity optomechanics is proposed to facilitate the generation of long‐distance entanglement and enable one‐way steering between magnons and phonons. This configuration involves two directly coupled cavities, with one interacting with magnons and the other coupling with a mechanical oscillator (i.e., phonons). By driving the microwave cavity with a weak squeezed vacuum field generated by a flux‐driven Josephson parametric amplifier, entanglement and one‐way steering can be further enhanced. Moreover, the results demonstrate that magnon–phonon entanglement and one‐way quantum steering exhibit robustness against temperature variations, which has significant implications for quantum information processing and storage.

Macroscopic quantum entanglement between an optomechanical cavity and a continuous field in presence of non-Markovian noise

Probing quantum entanglement with macroscopic objects allows us to test quantum mechanics in new regimes. One way to realize such behavior is to couple a macroscopic mechanical oscillator to a continuous light field via radiation pressure. In view of this, the system that is discussed comprises an optomechanical cavity driven by a coherent optical field in the unresolved sideband regime where we assume Gaussian states and dynamics. We develop a framework to quantify the amount of entanglement in the system numerically. Different from previous work, we treat non-Markovian noise and take into account both the continuous optical field and the cavity mode. We apply our framework to the case of the Advanced Laser Interferometer Gravitational-Wave Observatory and discuss the parameter regimes where entanglement exists, even in the presence of quantum and classical noises. Published by the American Physical Society 2024

Perspectives on phononic waveguides for on-chip classical and quantum transduction

Phononic waveguides (PnWGs) are devices with rationally designed periodic structures to manipulate mechanical oscillations and to engineer and control the propagation of acoustic waves, thus allowing for frequency and band selection of wave transmission and routing, promising for both classical and quantum transduction on chip-scale platforms with various constituent materials of interest. They can be incorporated into both electromechanical and optomechanical signal transduction schemes. Here, we present an overview of emerging micro/nanoscale PnWGs and offer perspectives for future. We evaluate the typical structural designs, frequency scaling, and phononic band structures of the PnWGs. Material choices, fabrication techniques, and characterization schemes are discussed based on different PnWG designs. For classical transduction schemes, an all-phononic integrated circuit perspective is proposed. Toward emerging quantum applications, the potential of utilizing PnWGs as universal interfaces and transduction channels has been examined. We envision PnWGs with extraordinary propagation properties, such as nonreciprocity and active tunability, can be realized with unconventional design strategies (e.g., inverse design) and advanced materials (e.g., van der Waals layered crystals), opening opportunities in both classical and quantum signal transduction schemes.

Zigzag optical cavity for sensing and controlling torsional motion

Precision sensing and manipulation of milligram-scale mechanical oscillators has attracted growing interest in the fields of table-top explorations of gravity and tests of quantum mechanics at macroscopic scales. Torsional oscillators present an opportunity in this regard due to their remarked isolation from environmental noise. For torsional motion, an effective employment of optical cavities to enhance optomechanical interactions—as already established for linear oscillators—so far faced certain challenges. Here, we propose a concept for sensing and manipulating torsional motion, where exclusively the torsional rotations of a pendulum are mapped onto the path length of a single two-mirror optical cavity. The concept inherently alleviates many limitations of previous approaches. A proof-of-principle experiment is conducted with a rigidly controlled pendulum to explore the sensing aspects of the concept and to identify practical limitations in a potential state-of-the art setup. Based on this study, we anticipate development of precision torque sensors utilizing torsional pendulums that can support sensitivities below 10−19Nm/Hz, while the motion of the pendulums are dominated by quantum radiation pressure noise at sub-microwatts of incoming laser power. These developments will provide horizons for experiments at the interface of quantum mechanics and gravity. Published by the American Physical Society 2024

Influence of donor or acceptor presence on excitation states in molecular chains: Nonadiabatic polaron approach.

In this paper, we considered a molecular structure that consists of a molecular chain and an additional molecule (donor or acceptor) that can inject (or remove) single excitation (vibron, electron, etc.) onto the molecular chain. We assumed that the excitation forms a self-trapped state due to the interaction with mechanical oscillations of the chain structure elements. We analyzed the energy spectra of the excitation and showed that its state (when it migrates to the molecular chain) has the properties of the nonadiabatic polaron state. The conditions under which the excitation can migrate from one subsystem to another one were considered. It was shown that the presence of a "donor" molecule cannot significantly change the properties of the excitation located on the molecular chain. At the same time, the molecular chain can affect the position of the energy level of the excitation localized on the donor subsystem. Indirectly, this can influence the process of excitation migration from one subsystem to another one. The influence of the basic energy parameters of the system and the environment temperature on this process are discussed. The entire system was assumed to be in thermal equilibrium with the environment.

A Method for Directly Observing Mechanical Oscillations in Photonic Structures Based on Porous Silicon Nanostructures

Due to their unique properties, porous silicon nanostructures have garnered much attention in photonics. For example, these structures can exhibit photoluminescence and are highly efficient in trapping light, making them ideal for applications such as biosensors, optical communication, and solar cells. The production of electromagnetic forces by light is a well-established concept, and the mechanism behind it is well-understood. In the past, we have used these forces to induce mechanical oscillations in a photonic structure based on porous silicon. Usually, to detect the oscillations, a high-precision vibrometer is utilized. However, we report a novel approach to visualizing photonic structure oscillations here. The traditional method of using a vibrometer as an indirect measurement tool has been replaced by one that involves directly observing the changes using a camera, digital movement amplification, a theoretical approximation, and FDTE simulations. This original technique provides researchers with a less expensive means of studying photonic structure movements. This proposal could be extended to other microscopic movements or for dynamical interferometric fringe analysis.

Towards the generation of mechanical Kerr-cats: awakening the perturbative quantum Moyal corrections to classical motion

The quantum to classical transition is determined by the interplay of a trio of parameters: dissipation, nonlinearity, and macroscopicity. Why is nonlinearity needed to see quantum effects? And, is not an ordinary pendulum quite nonlinear already? In this manuscript, we discuss the parameter regime where the dynamics of a massive oscillator should be quantum mechanical in the presence of dissipation. We review the outstanding challenge of the dynamical generation of highly quantum mechanical cat states of a massive ‘pendulum’, known as Kerr-cats. We argue that state-of-the-art cold atom experiments may be in a position to reach such a nonlinear regime, which today singles out superconducting quantum circuits. A way to stabilize Schrödinger cat superpositions of a mechanical atomic oscillator via parametric squeezing and further protected by an unusual form of quantum interference is discussed. The encoding of a neutral atom Kerr-cat qubit is proposed.

Automatic Detection and Self-Adjustment Compensation for Mechanical Oscillations and Disturbances in Servo Systems

Automatic Detection and Self-Adjustment Compensation for Mechanical Oscillations and Disturbances in Servo Systems

Harnessing synthetic active particles for physical reservoir computing

The processing of information is an indispensable property of living systems realized by networks of active processes with enormous complexity. They have inspired many variants of modern machine learning, one of them being reservoir computing, in which stimulating a network of nodes with fading memory enables computations and complex predictions. Reservoirs are implemented on computer hardware, but also on unconventional physical substrates such as mechanical oscillators, spins, or bacteria often summarized as physical reservoir computing. Here we demonstrate physical reservoir computing with a synthetic active microparticle system that self-organizes from an active and passive component into inherently noisy nonlinear dynamical units. The self-organization and dynamical response of the unit are the results of a delayed propulsion of the microswimmer to a passive target. A reservoir of such units with a self-coupling via the delayed response can perform predictive tasks despite the strong noise resulting from the Brownian motion of the microswimmers. To achieve efficient noise suppression, we introduce a special architecture that uses historical reservoir states for output. Our results pave the way for the study of information processing in synthetic self-organized active particle systems.

Nonreciprocal macroscopic tripartite entanglement in atom-optomagnomechanical system

We investigate how to generate the nonreciprocal macroscopic tripartite entanglement among the atomic ensemble, ferrimagnetic magnon and mechanical oscillator in a hybrid atom-optomagnomechanical system, where an ensemble of two-level atoms and a yttrium iron garnet micro-bridge supporting the magnon and mechanical modes are placed in a spinning optical resonator driven by a laser field. The phonon being the quantum of the mechanical mode interacts with the magnon and the optical photon via magnetostriction and radiation pressure, respectively, and meanwhile the photon couples to the atomic ensemble. The results show that not only all bipartite entanglements but also the genuine tripartite entanglement among the atomic ensemble, magnon and phonon could be generated at the steady state. Moreover, the nonreciprocity of atom-magnon-phonon entanglement can be obtained with the aid of the optical Sagnac effect by spinning the resonator, in which the entanglement is present in a chosen driving direction but disappears in the other direction. The nonreciprocal macroscopic tripartite entanglement is robust against temperature and could be flexibly controlled by choosing the system parameters. Our work enriches the study of macroscopic multipartite quantum states, which may have potential applications in the development of quantum information storage and the construction of multi-node chiral quantum network.

Quantum retrodiction in Gaussian systems and applications in optomechanics

What knowledge can be obtained from the record of a continuous measurement about the quantum state of the measured system at the beginning of the measurement? The task of quantum state retrodiction, the inverse of the more common state prediction, is rigorously addressed in quantum measurement theory through retrodictive positive operator-valued measures (POVMs). This introduction to this general framework presents its practical formulation for retrodicting Gaussian quantum states using continuous-time homodyne measurements and applies it to optomechanical systems. We identify and characterize achievable retrodictive POVMs in common optomechanical operating modes with resonant or off-resonant driving fields and specific choices of local oscillator frequencies in homodyne detection. In particular, we demonstrate the possibility of a near-ideal measurement of the quadrature of the mechanical oscillator, giving direct access to the position or momentum distribution of the oscillator at a given time. This forms the basis for complete quantum state tomography, albeit in a destructive manner.

Weakly nonlinear analysis on synchronization and oscillation quenching of coupled mechanical oscillators

Various oscillatory phenomena occur in the world. Because some are associated with abnormal states (e.g. epilepsy), it is important to establish ways to terminate oscillations by external stimuli. However, despite the prior development of techniques for stabilizing unstable oscillations, relatively few studies address the transition from oscillatory to resting state in nonlinear dynamics. This study mainly analyzes the oscillation-quenching of metronomes on a platform as an example of such transitions. To facilitate the analysis, we describe the impulsive force (escapement mechanism) of a metronome by a fifth-order polynomial. By performing both averaging approximation and numerical simulation, we obtain a phase diagram for synchronization and oscillation quenching. We find that quenching occurs when the feedback to the oscillator increases, which will help explore the general principle regarding the state transition from oscillatory to resting state. We also numerically investigate the bifurcation of out-of-phase synchronization and beat-like solution. Despite the simplicity, our model successfully reproduces essential phenomena in interacting mechanical clocks, such as the bistability of in-phase and anti-phase synchrony and oscillation quenching occurring for a large mass ratio between the oscillator and the platform. We believe that our simple model will contribute to future analyses of other dynamics of mechanical clocks.

Flag Fluttering‐Triggered Piezoelectric Energy Harvester at Low Wind Speed Conditions

Flow‐induced vibrations are common occurrences in various fluid–solid interaction systems existing in nature. One way to transform this vibrational mechanical energy into a usable form is through energy harvesters. This study examines the performance of a piezoelectric energy harvester, where mechanical oscillations result from the fluttering flags made of various fabrics. Flags, made of commonly encountered fabrics, are attached to a cantilever beam inside a wind tunnel with a 30 × 30 cm test section, allowing the airflow to be adjusted between 0 and 10 m s−1. The alpaca flag, with dimensions corresponding to an aspect ratio of 2, can produce meaningful electricity even at a wind speed as low as ≈3.8 m s−1. As the wind speed increases, the fluttering frequency of this flag configuration becomes 10.9 Hz at a wind speed of 5 m s−1, coinciding with the natural frequency of the first mode shape. In this specific arrangement, the structural deformation of the piezoelectric patch on the beam surface is maximized, allowing the harvester system to produce a root mean square voltage of 5 V with a relatively high maximum power of 98 μW.

Piezo-tribo-electric nanogenerator based on BCZT/MCNTs/PDMS piezoelectric composite for compressive energy harvesting

BackgroundThis work has developed a novel piezo-tribo-electric nanogenerator (P-TENG) that is capable of converting mechanical energy into electrical energy when operating in compressive mode. MethodsAn arch-shaped P-TENG device was formed using an optimal piezoelectric polymer composite, which was fabricated using a polydimethylsiloxane (PDMS) matrix that was modified with piezoelectric (Ba0.85Ca0.15) (Ti0.90Zr0.10)O3 (BCZT) ceramic particles and electrically conductive multi-walled carbon nanotubes (MCNTs). A high filler loading of BCZT (40, 50, 60 wt%) and 3 wt% of MCNTs was formed into a 0–3 connectivity composite. ResultsThe P-TENG device containing 50 wt% BCZT exhibited the highest electrical output (VOC ∼ 39.7 V, ISC ∼ 1.9 µA, and maximum power ∼ 157.7 µW), compared to the other composites, when subjected to an alternating compressive load of 500 N at a 1 Hz frequency. ConclusionsThis research provides new composite formulations for elastomeric-based energy generators that are responsive to low frequency mechanical oscillations.

Regulation of mechanical force on cardiomyocytes beating

The mechanical behavior of cardiomyocytes plays an essential role in maintaining life and health. It is traditionally believed that both electrical signals and chemical signals modulate the cardiomyocytes behaviors. Recent discoveries have elucidated that the physical cues of microenvironment can regulate cell activities such as proliferation, spreading, migration, and differentiation. However, there is still limited research on regulating cardiomyocytes beating through mechanical force. Herein we prepare different polyacrylamide gels coated with different cell adhesion ligand proteins to simulate the physical microenvironment of cardiomyocytes. Then the mechanical loading forces are loaded by using a tungsten probe to stretch elastic hydrogels which can emulate the mechanical oscillations induced by the beating of adjacent cardiomyocytes. We investigate the responsive behavior of cardiomyocytes to external mechanical oscillations within various physical microenvironments. Firstly, we load 1 Hz mechanical oscillation on the matrix (<i>E</i> = 11 kPa) with different kinds and concentrations of ligands (0, 5, 20, 100 μg/mL) to stimulate cardiomyocytes and observe their mechanical response behavior. Our findings indicate that all kinds of ligands including Laminin, Fibronectin and Collagen I , can mediate the cardiomyocytes response to extrinsic mechanical oscillatory stimuli, which might be due to distinct mechanisms of mechanical force coupling (Fig. (b)). This suggests that mechanical force signals can regulate the beating of cardiomyocytes through matrix-ligand-cell signaling pathway, thereby inducing intercellular coupled oscillations for rhythmic control of cardiomyocytes. Cardiomyocytes cultured on the matrix coated with 20 μg/mL Laminin show the highest and most stable response fraction. We hypothesize that there exist dual force transduction pathways for Laminin binding to integrin and dystrophin glycoprotein complex (DGC) (Fig. (a)). We further analyze the cardiomyocytes behaviors under mechanical oscillation with different values of substrate stiffness (<i>E</i> = 1.8, 11, 27 kPa) and concentrations of Laminin (0, 5, 20, 100 μg/mL). We find that cardiomyocytes cultured on 1.8 kPa coated with 20 μg/mL Laminin show the highest response fraction (Fig. (c)). Our results demonstrate that the stiffness of substrate, the type and density of cell adhesion ligands, as well as the strength and rhythm of the mechanical signals can synergetically affect the cardiomyocytes responses to external mechanical stimulations, which provides the foundation for understanding the diseases such as cardiac arrhythmias and heart failure following myocardial infarction.

Nanobody-loaded nanobubbles targeting the G250 antigen with ultrasound/photoacoustic/fluorescence multimodal imaging capabilities for specifically enhanced imaging of RCC.

Clinicians have attempted to discover a noninvasive, easy-to-perform, and accurate method to distinguish benign and malignant renal masses. The targeted nanobubbles (NBs) we constructed that target the specific membrane antigen of renal cell carcinoma (RCC), G250, and contain indocyanine green (ICG) provide multimodal enhanced imaging capability in ultrasound/photoacoustic/fluorescence for RCC which may possibly solve this problem. In this study, we encapsulated ICG in the lipid shell of the NBs by mechanical oscillation, then anti-G250 nanobodies (AGN) were coupled to the surfaces by the biotin-streptavidin bridge method, and the nanobubble named AGN/ICG-NB was completely constructed. The average particle diameter of the prepared AGN/ICG-NBs was (427.2 ± 4.50) nm, and the zeta potential was (-13.33 ± 1.01) mV. Immunofluorescence and flow cytometry confirmed the specific binding capability of AGN/ICG-NBs to G250-positive cells. In vitro imaging experiments confirmed the multimodal imaging capability of AGN/ICG-NBs, and the in vivo imaging experiments demonstrated the specifically enhanced ability of AGN/ICG-NBs for ultrasound/photoacoustic/fluorescence imaging of human-derived RCC tumors. The biosafety of AGN/ICG-NB was verified by CCK-8 assay, organ H&E staining and blood biochemical indices. In conclusion, the targeted nanobubbles we prepared with ultrasound/photoacoustic/fluorescence multimodal imaging capabilities provide a potentially feasible approach to address the need for early diagnosis and differential diagnosis of renal masses.

Mechanism Analysis and Oscillation Suppression of the False Triggering Oscillation for Parallel-Connected GaN Devices

Mechanism Analysis and Oscillation Suppression of the False Triggering Oscillation for Parallel-Connected GaN Devices