青木 健一郎 (アオキ ケンイチロウ)

Aoki, Kenichiro

写真a

所属(所属キャンパス)

経済学部 (日吉)

職名

教授

HP

外部リンク

経歴 【 表示 / 非表示

  • 1989年08月

    UCLA物理学科,Research Associate

  • 1992年09月
    -
    1993年05月

    UCLA物理学科 ,AdjunctAssociateProfessor

  • 1993年06月
    -
    1995年03月

    東京工業大学 理学部 物理学科 助手

  • 1995年04月
    -
    1999年03月

    大学助教授(経済学部)

  • 1999年04月
    -
    継続中

    大学教授(経済学部)

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学歴 【 表示 / 非表示

  • 1984年03月

    東京大学, 理学部

    大学, 卒業

  • 1985年10月

    Princeton 大学, 物理学科

    アメリカ合衆国, 大学院, 修了, 修士

  • 1989年10月

    Princeton 大学, 物理学科

    アメリカ合衆国, 大学院, 修了, 博士

学位 【 表示 / 非表示

  • Ph.D., Princeton大学, 論文, 1989年10月

 

研究分野 【 表示 / 非表示

  • 素粒子・原子核・宇宙線・宇宙物理 (素粒子理論, 弦理論)

  • 数理物理・物性基礎 (非平衡の物理)

 

著書 【 表示 / 非表示

  • 現代物理学を学びたい人へ - 原子から宇宙まで -

    青木 健一郎, 慶應義塾大学出版会, 2011年05月

  • 力学(コア・テキスト)

    青木 健一郎, サイエンス社, 2011年

  • 素粒子物理学

    原 康夫,稲見 武夫,青木 健一郎, 朝倉書店, 2000年

論文 【 表示 / 非表示

  • Fluctuation spectroscopy of surface melting of ice with and without impurities

    Mitsui T., Aoki K.

    Physical Review E (Physical Review E)  99 ( 1 )  2019年01月

    ISSN  24700045

     概要を見る

    © 2019 American Physical Society. Water is ubiquitous, and the surface properties of ice have been studied for some time, due to their importance. A liquidlike layer (LLL) is known to exist on ice, below the melting point. We use surface thermal fluctuation spectroscopy to study the LLL, including its thickness, for pure ice, and for ice with impurities. We find that the properties of the LLL are experimentally those of liquid water, with thickness much smaller than previous results. We also find that impurities cause the LLL to be thicker, and quite inhomogeneous, with properties depending on the dopant.

  • Dynamically enhanced low-coherence interferometry

    Mitsui T., Aoki K.

    Review of Scientific Instruments (Review of Scientific Instruments)  89 ( 9 )  2018年09月

    ISSN  00346748

     概要を見る

    © 2018 Author(s). In the investigations of inhomogeneous media, availability of methods to study the interior of the material without affecting it is valuable. Optical coherence tomography provides such a functionality by providing depth resolved images of semi-transparent objects non-invasively. This is especially useful in medicine and is used not only in research but also in clinical practice. Optical coherence tomography characterizes each cross section by its reflectance. The basic physics principle underlying optical coherence tomography is low-coherence interferometry, which is combined with lateral scanning to produce cross sections. It is clearly desirable to obtain more detailed information regarding each cross section, if available. We have developed a system which measures the fluctuation spectra at all depths in low-coherence interferometry. By providing more information for each cross section, this can in principle be effective in tissue characterization and pathological diagnosis. The system uses the time dependence of the low-coherence interferometry data to obtain the fluctuation spectrum at each depth. Additionally, noise reduction is applied to obtain the spectra without unwanted noise, such as shot-noise, which can swamp the signal. The measurement system is applied to samples with no external stimuli, and depth resolved thermal fluctuation spectra of the samples are obtained. These spectra are compared with their corresponding theoretical expectations and are found to agree. The measurement system requires dualizing the detectors in the low-coherence interferometer but otherwise requires little additional equipment. The measurements were performed in ten to a hundred seconds.

  • Thermal interface fluctuations of liquids and viscoelastic materials

    Aoki K., Mitsui T.

    Progress of Theoretical and Experimental Physics (Progress of Theoretical and Experimental Physics)  2018 ( 4 )  2018年04月

    ISSN  2050-3911

     概要を見る

    © 2018 Physical Society of Japan. All rights reserved. Spectra of thermal fluctuations of a wide range of interfaces, from liquid/air, viscoelastic material/ air, liquid/liquid to liquid/viscoelastic material interfaces, were measured over a 100 Hz to 10MHz frequency range. The obtained spectra were compared with the fluctuation theory of interfaces, and found to be mostly in quite good agreement, when the theory was generalized to apply to thermal fluctuations of liquid/viscoelastic material interfaces. The loss modulus of viscoelastic materials has been incorporated into the theory, and its effects observed experimentally. The spectra were measured using a system that combines light reflection, statistical noise reduction through averaged correlations, and confocal microscopy. It requires only a small area of the interface (∼1μm2), relatively short times for measurements (≲ few min), and can also be applied to highly viscous materials.

  • Order and chaos in the one-dimensional ϕ<sup>4</sup> model: N-dependence and the Second Law of Thermodynamics

    Hoover W., Aoki K.

    Communications in Nonlinear Science and Numerical Simulation (Communications in Nonlinear Science and Numerical Simulation)  49   192 - 201 2017年08月

    ISSN  10075704

     概要を見る

    © 2017 Elsevier B.V. We revisit the equilibrium one-dimensional ϕ4 model from the dynamical systems point of view. We find an infinite number of periodic orbits which are computationally stable. At the same time some of the orbits are found to exhibit positive Lyapunov exponents! The periodic orbits confine every particle in a periodic chain to trace out either the same or a mirror-image trajectory in its two-dimensional phase space. These “computationally stable” sets of pairs of single-particle orbits are either symmetric or antisymmetric to the very last computational bit. In such a periodic chain the odd-numbered and even-numbered particles’ coordinates and momenta are either identical or differ only in sign. “Positive Lyapunov exponents” can and do result if an infinitesimal perturbation breaking a perfect two-dimensional antisymmetry is introduced so that the motion expands into a four-dimensional phase space. In that extended space a positive exponent results. We formulate a standard initial condition for the investigation of the microcanonical chaotic number dependence of the model. We speculate on the uniqueness of the model's chaotic sea and on the connection of such collections of deterministic and time-reversible states to the Second Law of Thermodynamics.

  • Observation of reflectance fluctuations in metals

    Mitsui T., Aoki K.

    Physical Review A (Physical Review A)  95 ( 4 )  2017年04月

    ISSN  24699926

     概要を見る

    © 2017 American Physical Society. Through the study of the power spectra of a monochromatic light beam reflected by metallic mirrors, fluctuations in their reflectance are observed. The power spectra were obtained down to a factor 10-6 below the standard quantum limit, with a dynamic range of 105 in frequency and power, using methods we developed. The properties of the spectra are investigated, and their dependence on the material is analyzed. The physics underlying the phenomenon is also discussed. These fluctuations provide a window into the degrees of freedom responsible for the reflection process in metals.

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KOARA(リポジトリ)収録論文等 【 表示 / 非表示

研究発表 【 表示 / 非表示

  • Observation of Spontaneous Quantum Fluctuations in Photon Absorption by Atoms

    青木 健一郎,三井 隆久

    The 12th Asia Pacific Physics Conference of AAPPS (幕張メッセ,千葉) , 2013年07月, 口頭(一般), The Association of Asia Pacific Physical Societies (AAPPS)

  • Direct Observations of Surface Thermal Fluctuations Below Shot Noise Levels

    青木 健一郎,三井 隆久

    The 12th Asia Pacific Physics Conference of AAPPS (幕張メッセ,千葉) , 2013年07月, ポスター(一般), The Association of Asia Pacific Physical Societies

競争的資金等の研究課題 【 表示 / 非表示

  • 散射雑音を除去した光計測を基盤とする揺らぎのダイナミックスの研究

    2015年04月
    -
    2020年03月

    文部科学省・日本学術振興会, 科学研究費助成事業, 青木 健一郎, 基盤研究(C), 補助金,  代表

Works 【 表示 / 非表示

  • 自然科学系を核とした教養教育の将来

    青木 健一郎

    横浜, 

    2003年07月
    -
    継続中

    その他, 共同

  • 文化系学生が学ぶ物理学実験

    青木 健一郎

    2002年11月
    -
    継続中

    その他

 

担当授業科目 【 表示 / 非表示

  • 物理学Ⅱ(実験を含む)

    2020年度

  • 物理学Ⅰ(実験を含む)

    2020年度

  • 自然科学Ⅰ

    2020年度

  • 自由研究セミナーb

    2020年度

  • 自由研究セミナーa

    2020年度

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