arXiv subjects

Masateru Taniguchi

Publications and source records attributed to Masateru Taniguchi.

5 recordsLinked to original sources

arXiv2026

Tracer-free Contactless Acoustic Microrheometry Quantifies Viscoelastic Spectrum of Phase-separated Condensates

The rheology of phase-separated condensates plays a central role in applications spanning advanced materials design and cellular processes, yet quantitative characterization of their viscoelasticity remains challenging due to the limitations of existing microrheological methods that require tracer particles or mechanical contact. Here, we establish tracer-free and contactless acoustic microrheometry as a versatile platform for quantifying the frequency-dependent complex shear modulus of single microscale condensates over 0.01-10 Hz. Using spatiotemporally controlled acoustic radiation force generated within a micro-acoustic resonator, this method deforms condensates for creep-recovery and oscillatory viscoelastic measurements. Quantitative validation using dextran condensates in a polyethylene-glycol continuous phase successfully captures their size- and frequency-dependent mechanical responses, while application to nucleic-acid condensates reveals salt-dependent internal viscoelastic changes at single-condensate resolution. By enabling quantitative dissection of condensate mechanics without invasive probes, acoustic microrheometry provides a broadly applicable framework for investigating phase-separated condensates across materials science, soft matter physics, biology, and beyond.

cond-mat.soft↗

arXiv2020

Contraction-free quantum state encoding by quantum tunneling in single molecules

Quantum computing is a unique computational approach that promises tremendous performance that cannot be achieved by classical computers, although several problems must be resolved to realize a practical quantum computing system for easy use. Here, we propose a new system and theory for quantum computing that employs single molecule confinement between electrodes. The striking features of this system are (i) an individual molecule that exhibits quantum tunneling can be regarded as a sequence of quantum gates, (ii) the quantum tunneling can be encoded onto an array of quantum bits and observed without the contraction of superposition states, and (iii) quantum computing by quantum tunneling can be performed at room temperature. An adenine molecule is adopted as the single molecule between electrodes, and conductance data are encoded onto quantum states including entangled states, depending on the conductance values. As an application of the new quantum system, molecule identification based on quantum computing by quantum tunneling is demonstrated.

quant-ph↗

arXiv2018

Life-Detection Technologies for the Next Two Decades

Since its inception six decades ago, astrobiology has diversified immensely to encompass several scientific questions including the origin and evolution of Terran life, the organic chemical composition of extraterrestrial objects, and the concept of habitability, among others. The detection of life beyond Earth forms the main goal of astrobiology, and a significant one for space exploration in general. This goal has galvanized and connected with other critical areas of investigation such as the analysis of meteorites and early Earth geological and biological systems, materials gathered by sample-return space missions, laboratory and computer simulations of extraterrestrial and early Earth environmental chemistry, astronomical remote sensing, and in-situ space exploration missions. Lately, scattered efforts are being undertaken towards the R&D of the novel and as-yet-space-unproven life-detection technologies capable of obtaining unambiguous evidence of extraterrestrial life, even if it is significantly different from Terran life. As the suite of space-proven payloads improves in breadth and sensitivity, this is an apt time to examine the progress and future of life-detection technologies.

astro-ph.EP↗

arXiv2013

Electrochemical response of biased nanoelectrodes in solution

Novel approaches to DNA sequencing and detection require the measurement of electrical currents between metal probes immersed in ionic solution. Here, we experimentally demonstrate that these systems maintain large background currents with a transient response that decays very slowly in time and noise that increases with ionic concentration. Using a non-equilibrium stochastic model, we obtain an analytical expression for the ionic current that shows these results are due to a fast electrochemical reaction at the electrode surface followed by the slow formation of a diffusion layer. During the latter, ions translocate in the weak electric field generated after the initial rapid screening of the strong fields near the electrode surfaces. Our theoretical results are in very good agreement with experimental findings.

cond-mat.mes-hall↗

arXiv2012

Bilayer Graphene Lateral Contacts for DNA Sequencing

Translocation of DNA through a nanopore with embedded electrodes is at the centre of new rapid inexpensive sequencing methods which allow distinguishing the four nucleobases by their different electronic structure. However, the subnanometer separation between nucleotides in DNA requires ultra-sharp probes. Here, we propose a device architecture consisting of a nanopore formed in bilayer graphene, with the two layers acting as separate electrical contacts. The 0.34 nm interlayer distance of graphene is ideally suited for electrical coupling to a single nucleobase, avoiding the difficulty of fabricating probes with subnanometer precision. The top and bottom graphene electrodes contact the target molecule from the same lateral side, removing the orders-of-magnitude tunneling current variations between smaller pyrimidine bases and larger purine bases. We demonstrate that incorporating techniques for molecular manipulation enables the proposed device to sequence single-stranded DNA and that it offers even the prospect of sequencing double-stranded DNA.

cond-mat.mes-hall↗