arXiv subjects

Hiroshi Yamaguchi

Publications and source records attributed to Hiroshi Yamaguchi.

At least 37 records · Page 2Linked to original sources

arXiv2022

Phononic-crystal cavity magnomechanics

Establishing a way to control magnetic dynamics and elementary excitations (magnons) is crucial to fundamental physics and the search for novel phenomena and functions in magnetic solid-state systems. Electromagnetic waves have been developed as means of driving and sensing in magnonic and spintronics devices used in magnetic spectroscopy, non-volatile memory, and information processors. However, their millimeter-scale wavelengths and undesired cross-talk have limited operation efficiency and made individual control of densely integrated magnetic systems difficult. Here, we utilize acoustic waves (phonons) to control magnetic dynamics in a miniaturized phononic crystal micro-cavity and waveguide architecture. We demonstrate acoustic pumping of localized ferromagnetic magnons, where their back-action allows dynamic and mode-dependent modulation of phononic cavity resonances. The phononic crystal platform enables spatial driving, control and read-out of tiny magnetic states and provides a means of tuning acoustic vibrations with magnons. This alternative technology enhances the usefulness of magnons and phonons for advanced sensing, communications and computation architectures that perform transduction, processing, and storage of classical and quantum information.

cond-mat.mes-hall↗

arXiv2022

A Kuramoto Network in a Single Nonlinear Microelectromechanical Device

This work presents a frequency multiplexed 3-limit cycles network in a multimode microelectromechanical nonlinear resonator. The network is composed of libration limit cycles and behaves in an analogous manner to a phase oscillator network. The libration limit cycles, being of low frequency, interact through the stress tuning of the resonator, and result in an all-to-all coupling that can be described by a Kuramoto model. Beyond the typically present cubic nonlinearity the modes in question do not require any special frequency ratios. Thus an interconnect free Kuramoto network is established within a single physical device without the need for electrical or optical coupling mechanisms between the individual elements.

physics.app-ph↗

arXiv2021

Buckling-induced quadratic nonlinearity in silicon phonon waveguide structures

We fabricated and characterized a single-crystal silicon phonon waveguide structure with lead zirconate titanate (PZT) piezoelectric transducers. The compressive stress in a silicon-on-insulator wafer causes a membrane waveguide to buckle, leading to the quadratic nonlinearity. The PZT transducer integrated in an on-chip configuration enables us to excite high-intensity mechanical vibration, which allows the characterization of nonlinear behavior. We observed a softening nonlinear response as a function of the drive power and demonstrated the mode shift and frequency conversion. This is the first report of the nonlinear behavior caused by the quadratic nonlinearity in a buckled phonon waveguide structure. This study provides a method to control the sign and the order of nonlinearity in a phonon waveguide by utilizing the internal stress, which allows the precise manipulation of elastic waves in phononic integrated circuits.

cond-mat.mes-hall↗

arXiv2021

The Librator: A new dynamical regime for nonlinear microelectromechanical devices

We present a novel mode of operation for Duffing-type nonlinear microelectromechanical (MEMS) devices whereby a self-sustained multi-frequency output is generated. This new librator regime creates a limit cycle around a dynamical fixed point, i.e. around fixed points within the rotating frame, whereas a traditional oscillator generates a limit cycle around a static fixed point. The librator limit cycles thus created do not change the global topology of the rotating frame phase space, but are constrained by it. Due to the Duffing nonlinearity different types of limit cycles may be generated within the same phase space, with each type possessing distinct dynamical features. Transitioning between these limit cycles requires crossing homoclinic bifurcations, which is done without generating chaos as the phase space dynamics are two dimensional. This work opens the possibility to the creation of a librator network in analogy with oscillator network, however this can be done in a single MEMS device.

cond-mat.mes-hall↗

arXiv2021

Non-equilibrium quadratic measurement-feedback squeezing in a micromechanical resonator

Measurement and feedback control of stochastic dynamics has been actively studied for not only stabilizing the system but also for generating additional entropy flows originating in the information flow in the feedback controller. In particular, a micromechanical system offers a great platform to investigate such non-equilibrium dynamics under measurement-feedback control owing to its precise controllability of small fluctuations. Although various types of measurement-feedback protocols have been demonstrated with linear observables (e.g., displacement and velocity), extending them to the nonlinear regime, i.e., utilizing nonlinear observables in both measurement and control, retains non-trivial phenomena in its non-equilibrium dynamics. Here, we demonstrate measurement-feedback control of a micromechanical resonator by driving the second-order nonlinearity (i.e., parametric squeezing) and directly measuring quadratic observables, which are given by the Schwinger representation of pseudo angular momentum (referred as Schwinger angular momentum). In contrast to that the parametric divergence occurs when the second-order nonlinearity is blindly driven, our measurement-feedback protocol enables us to avoid such a divergence and to achieve a strong noise reduction at the level of $-5.1\pm 0.2$ dB. This strong noise reduction originates in the effective cooling included in our measurement-feedback protocol, which is unveiled by investigating entropy production rates in a coarse-grained model. Our results open up the possibility of not only improving noise-limited sensitivity performance but also investigating entropy production in information thermodynamic machines with nonlinear measurement and feedback.

cond-mat.mes-hall↗

arXiv2021

Gigabit Ethernet Daisy-Chain on FPGA for COMET Read-out Electronics

The COMET experiment at J-PARC aims to search for the neutrinoless transition of a muon to an electron. We have developed the readout electronics board called ROESTI for the COMET straw tube tracker. We plan to install the ROESTI in the gas manifold of the detector. The number of vacuum feedthroughs needs to be reduced due to space constraints and cost limitations. In order to decrease the number of vacuum feedthroughs drastically, we developed a network processor with a daisy-chain function of Gigabit Ethernet for the FPGA on the ROESTI. We implemented two SiTCPs, which are hardware-based TCP processors for Gigabit Ethernet, in the network processor. We also added the data path controllers which handle the Ethernet frames and the event data. The network processor enables ROESTI to process the slow control over UDP/IP and to transfer event data over TCP/IP. By using the network processor, we measured the throughput, the stability, and the data loss rate for two to six ROESTIs. In any number of boards, the throughput of the event data transfer achieved the theoretical limit of TCP over the Gigabit Ethernet stably and ROESTI stably sent 100% of the data.

physics.ins-det↗

arXiv2021

Generation and propagation of topological solitons in a chain of coupled parametric-micromechanical-resonator arrays

Using a coupled parametric-resonator array for generating and propagating a topological soliton in its rotating-frame phase space is theoretically and numerically investigated. In an analogy with the well-known phi4 model, the existence of a soliton is topologically protected as the boundary of two different phase domains of parametric oscillation. Numerical simulation indicates that the propagation can be triggered by switching of the phase state of one specific resonator, and the effects of damping, collision, and the symmetry lifting by harmonic drive on the propagation dynamics are studied. The topological soliton can be implemented by using electromechanical resonators, which allow its propagation dynamics to be precisely electrically controlled and provide a fully controlled on-chip test bed for the study of a topological soliton.

nlin.PS↗

arXiv2020

Near-field cavity optomechanical coupling in a compound semiconductor nanowire

A III-V compound semiconductor nanowire is an attractive material for a novel hybrid quantum interface that interconnects photons, electrons, and phonons through a wavelength-tunable quantum structure embedded in its free-standing structure. In such a nanomechanical element, however, a challenge is how to detect and manipulate a small number of phonons via its tiny mechanical motion. A solution would be to couple an optical cavity to a nanowire by introducing the ``cavity optomechanics'' framework, but the typical size difference between them becomes a barrier to achieving this. Here, we demonstrate near-field coupling of a silica microsphere cavity and an epitaxially grown InP/InAs free-standing nanowire. The evanescent optomechanical coupling enables not only fine probing of the mechanical motion by balanced homodyne interferometry but also tuning of the resonance frequency, linewidth, Duffing nonlinearity, and vibration axis in the nanowire. Combining this cavity optomechanics with epitaxial nanowire engineering opens the way to novel quantum metrology and information processing.

cond-mat.mes-hall↗

arXiv2020

Rare-earth-mediated opto-mechanical system in the reversed dissipation regime

Strain-mediated interaction between phonons and telecom photons is demonstrated using excited states of erbium ions embedded in a mechanical resonator. Owing to the extremely long-lived nature of rare-earth ions, the dissipation rate of the optical resonance falls below that of the mechanical one. Thus, a reversed dissipation regime is achieved in the optical frequency region. We experimentally demonstrate an opto-mechanical coupling rate 21.7 Hz, and numerically reveal that the interaction causes stimulated excitation of erbium ions. Numerical analyses further indicate the possibility of g_0 exceeding the dissipation rates of erbium and mechanical systems, thereby leading to single-photon strong coupling. This strain-mediated interaction moreover involves the spin degree of freedom, and has a potential to be extended to highly-coherent opto-electro-mechanical hybrid systems in the reversed dissipation regime.

physics.optics↗

arXiv2020

Scalable quantum computation architecture using always-on Ising interactions via quantum feedforward

Here, we propose a way to control the interaction between qubits with always-on Ising interaction. Unlike the standard method to change the interaction strength with unitary operations, we fully make use of non-unitary properties of projective measurements so that we can effectively turn the interaction on or off via feedforward. Our scheme is useful to generate two- or three-dimensional cluster states that are universal resources for fault-tolerant quantum computation with this scheme, and it provides an alternative way to realize a scalable quantum pro

quant-ph↗

arXiv2020

A Generic Rotating-Frame-Based Approach to Chaos Generation in Nonlinear MEMS NEMS Resonators

This work provides a low-power method for chaos generation which is generally applicable to nonlinear M/NEMS resonators. The approach taken is independent of the material, scale, design, and actuation of the device in question; it simply assumes a good quality factor and a Duffing type nonlinearity, features that are commonplace to M/NEMS resonators. The approach models the rotating-frame dynamics to analytically constrain the parameter space required for chaos generation. By leveraging these common properties of M/NEMS devices, a period-doubling route to chaos is generated using an order-of-magnitude smaller forcing than typically reported in the literature.

cond-mat.mes-hall↗

arXiv2019

Radiation hardness study for the COMET Phase-I electronics

Radiation damage on front-end readout and trigger electronics is an important issue in the COMET Phase-I experiment at J-PARC, which plans to search for the neutrinoless transition of a muon to an electron. To produce an intense muon beam, a high-power proton beam impinges on a graphite target, resulting in a high-radiation environment. We require radiation tolerance to a total dose of $1.0\,\mathrm{kGy}$ and $1\,\mathrm{MeV}$ equivalent neutron fluence of $1.0\times10^{12}\,\mathrm{n_{eq}\,cm^{-2}}$ including a safety factor of 5 over the duration of the physics measurement. The use of commercially-available electronics components which have high radiation tolerance, if such components can be secured, is desirable in such an environment. The radiation hardness of commercial electronic components has been evaluated in gamma-ray and neutron irradiation tests. As results of these tests, voltage regulators, ADCs, DACs, and several other components were found to have enough tolerance to both gamma-ray and neutron irradiation at the level we require.

physics.ins-det↗

arXiv2019

Real-space characterization of cavity-coupled waveguide systems in hypersonic phononic crystals

A phononic crystal formed in a suspended membrane provides full confinement of hypersonic waves and thus realizes a range of chip-scale manipulations. In this letter, we demonstrate the mode-resolved real-space characterization of the mechanical vibration properties in cavities and waveguide systems. Multiple resonant modes are independently characterized in various designed cavities, and wavelength-scale high-$Q$ resonances up to $Q=$ 4200 under atmospheric conditions are confirmed. This also reveals that the waveguide allows us to resolve single-mode wave transmission and thereby drive evanescently-coupled cavities. The methods offer a significant tool with which to build compact and low-power microwave phononic circuitry for signal processing and hybrid quantum system applications.

physics.app-ph↗

arXiv2019

Optically probing Schwinger angular momenta in a micromechanical resonator

We report an observation of phononic Schwinger angular momenta, which fully represent twomode states in a micromechanical resonator. This observation is based on simultaneous optical detection of the mechanical response at the sum and difference frequency of the two mechanical modes. A post-selection process for the measured signals allows us to extract a component of phononic Schwinger angular momenta. It also enables us to conditionally prepare two-mode squeezed (correlated) states from a randomly excited (uncorrelated) state. The phononic Schwinger angular momenta could be extended to high-dimensional symmetry (e.g. SU(N) group) for studying multipartite correlations in non-equilibrium dynamics with macroscopic objects.

cond-mat.mes-hall↗

arXiv2019

Verification of the Herschel-Bulkley Model by a Visualization Experiment of a Elastoviscoplastic Yield-Stress Fluid Flow in Straight and Bended Tubes

The elastoviscoplastic yield-stress fluid flows in a horizontal straight tube and a bended tube have been investigated using hydrogen bubble visualization method. The experimental results are used to verify the empirical Herschel-Bulkley model. Both experimental and theoretical investigations well predict the yield-stress fluid flow behaviors. It is found that the significant factors influencing on the predictions of the Herschel-Bulkley model are the yield stress, viscosity and viscoelasticity. For the yield-stress flows in the bended tube, a more delicate constitutive model with consideration of the viscoelastic effects is expected for accurately predicting the flow behaviors.

physics.flu-dyn↗

arXiv2019

Acoustic Kerr nonlinearity of wave propagation in a planar nanoelectromechanical waveguide

Nonlinearity is the key to introducing novel concepts in various technologies utilizing traveling waves. In contrast to the field of optics, where highly functional devices have been developed using optical Kerr nonlinearity, such a nonlinear effect in acoustic devices has yet to be fully exploited. Here, we show that most fundamental nonlinear phenomena of self-phase modulation (SPM), cross-phase modulation (XPM) and four-wave mixing (FWM) caused by the acoustic Kerr effect are quantitatively characterized using a newly developed platform consisting of a planar nanoelectromechanical waveguide (NEMW). Combining the cutting-edge technology of a high crystalline quality NEMW with a piezoelectric interdigital transducer (IDT), we efficiently excite an intense and long-lived traveling wave sufficiently to induce and characterize acoustic nonlinearity. The observed nonlinear phenomena are precisely described by the model using the nonlinear Schrödinger (NLS) equation, so that this architecture enables the nonlinear dynamics to be perfectly tailored. The flexible and integratable platform extends the ability to manipulate acoustic wave propagation on a chip, thus offering the potential to develop highly functional devices and study novel nonlinear acoustics.

cond-mat.mes-hall↗

arXiv2019

Modal Analysis Investigation of Mechanical Kerr Frequency Combs

The aim of this work is to theoretically investigate the possibility of Kerr frequency combs in mechanical systems. In particular, whether microelectrome-chanical devices (MEMS) can be used to generate frequency combs in a manner that is analogous to the optical frequency combs generated in optical microresona-tors with Kerr-type nonlinearity. The analysis assumes a beam-like micromechani-cal structure, and starting from the Euler-Bernoulli beam equation derives the nec-essary conditions in parameter space for the comb generation. The chapter equally presents potential means for the physical implementation of mechanical Kerr combs.

cond-mat.mes-hall↗

arXiv2019

Strain-induced exciton decomposition and anisotropic lifetime modulation in a GaAs micromechanical resonator

We demonstrate mechanical modulations of the exciton lifetime by using vibrational strain of a gallium arsenide (GaAs) resonator. The strain-induced modulations have anisotropic dependences on the crystal orientation, which reveals the origin of these modulations to be the piezoelectric effect. Numerical analyses based on the tunneling model clarify that the mechanical strain modulates the internal electric field and spatially separates the electrons and holes, leading to non-radiative exciton decomposition. This carrier separation also generates an optomechanical back-action force from the photon to the resonator. Therefore, these results indicate that the mechanical motion can be self-modulated by exciton decays, which enables one to control the thermal noise of the resonators and provides a photon-exciton-phonon interaction in solid-state systems.

physics.optics↗