arXiv subjects

Yoshio Mita

Publications and source records attributed to Yoshio Mita.

6 recordsLinked to original sources

arXiv2024

ARIM-mdx Data System: Towards a Nationwide Data Platform for Materials Science

In modern materials science, effective and high-volume data management across leading-edge experimental facilities and world-class supercomputers is indispensable for cutting-edge research. However, existing integrated systems that handle data from these resources have primarily focused just on smaller-scale cross-institutional or single-domain operations. As a result, they often lack the scalability, efficiency, agility, and interdisciplinarity, needed for handling substantial volumes of data from various researchers. In this paper, we introduce ARIM-mdx data system, aiming at a nationwide data platform for materials science in Japan. Currently in its trial phase, the platform has been involving 11 universities and institutes all over Japan, and it is utilized by over 800 researchers from around 140 organizations in academia and industry, being intended to gradually expand its reach. The ARIM-mdx data system, as a pioneering nationwide data platform, has the potential to contribute to the creation of new research communities and accelerate innovations.

cs.DC↗

arXiv2023

Experimental demonstration of position-controllable topological interface states in high-frequency topological integrated circuits

Topological integrated circuits are integrated-circuit realizations of topological systems. Here we show an experimental demonstration by taking the case of the Kitaev topological superconductor model. An integrated-circuit implementation enables us to realize high resonant frequency as high as 13GHz. We explicitly observe the spatial profile of a topological edge state. In particular, the topological interface state between a topological segment and a trivial segment is the Majorana-like state. We construct a switchable structure in the integrated circuit, which enables us to control the position of a Majorana-like interface state arbitrarily along a chain. Our results contribute to the development of topological electronics with high frequency integrated circuits.

cond-mat.mes-hall↗

arXiv2022

Universal quantum computer based on Carbon Nanotube Rotators

We propose a universal quantum computer based on a chain of carbon nanotube rotators where one metallic plate is attached to each rotator. The dynamical variable is the rotational angle $ϕ$. The attached plate connected to ground electrostatically interacts with two fixed plates. Two angle positions $ϕ=0,π$ are made stable by applying a voltage difference between the attached plate and the two fixed plates. We assign $ϕ=0$ and $π$ to the qubit states $|0\rangle$ and $|1\rangle $. Then, considering a chain of rotators, we construct the arbitrary phase-shift gate, the NOT gate and the Ising gate, which constitute a set of universal quantum gates. They are executed by controlling the voltage between various plates.

quant-ph↗

arXiv2022

Universal quantum computation based on Nano-Electro-Mechanical Systems

We propose to use a buckled plate as a qubit, where a double-well potential is mechanically produced by pushing the plate from both the sides. The right and left positions of the plate are assigned to be quantum states $|0\rangle $ and $|1\rangle $. Quantum effects emerge when the displacement is of the order of picometers, although the size of a buckled plate is of the order of $1μm$. The NOT gate is executed by changing the buckling force acting on the plate, while the Pauli-Z gate and the phase-shift gate are executed by applying electric field. A two-qubit phase shift gate is materialized with the use of an electrostatic potential. They constitute a set of universal quantum gates. An examination of material parameters leads to a feasibility of a NEMS(Nano-Electro-Mechanical System)-based quantum computer.

quant-ph↗

arXiv2022

Nonvolatile bistable memory and Ising machine based on Micro-Electro-Mechanical Systems

We propose an Ising machine made of microelectromechanical systems (MEMS), where the annealing process is automatically executed by a dissipation mechanism. The core structure is a series of buckled plates. Two stable positions of each plate (left and right) represent its binary state acting as a bit so that a plate works as a mechanical memory. The electrostatic interaction between adjacent plates is introduced by applying voltage. Plates continue to flip between two stable buckled positions until the series of plates reaches a local minimum due to the damping of the mechanical motion. \red{First, we design Ising machines simulating a ferromagnetic (FM) interaction and an antiferromagnetic (AF) interaction separately. Then, we propose a fully-connected MEMS\ network representing a coexistence system of FM and AF interactions in an arbitrary way, by way of which an arbitrary combinatorial problem described by the Ising model can be solved.} The present mechanism works at room temperature without external magnetic field, which is very different from the standard classical or quantum annealing mechanism.

physics.app-ph↗

arXiv2020

Tunable third harmonic generation in the vacuum ultraviolet region using dielectric nanomembranes

Tunable coherent light sources operating in the vacuum ultraviolet (VUV) region in 100-200-nm (6-12 eV) wavelength range have important spectroscopic applications in many research fields, including time-resolved angle-resolved photoemission spectroscopy (ARPES). Recent advances in laser technology have enabled the upconversion of visible femtosecond lasers to the vacuum and extreme ultraviolet regions. However, the complexity of their experimental setups and the scarcity of bulk nonlinear crystals for VUV generation have hampered its widespread use. Here, we propose the use of a free-standing dielectric nanomembranes as a simple and practical method for tunable VUV generation. We demonstrate that third harmonic VUV light is generated with sufficient intensity for spectroscopic applications from commercially available SiO2 nanomemebranes of submicron thicknesses under excitation with visible femtosecond laser pulses. The submicron thickness of the nanomembranes is optimal for maximize the VUV generation efficiency and prevents self-phase modulation and spectral broadening of the fundamental beam. The observed VUV photons are up to 10^7 photons per pulse at 157 nm with 1-kHz repetition rate, corresponding to a conversion efficiency of 10^-6. Moreover, the central VUV wavelength can be tuned in 146-190-nm wavelength range by changing the fundamental wavelength. We also explore material and thickness dependence with experiments and calculations. The presented results suggest that dielectric nanomembranes can be used as a practical nonlinear media for VUV spectroscopic applications.

physics.optics↗