グドナソン, スヴェン ビヤルケ (グドナソン スヴェン ビヤルケ)

Gudnason, Sven Bjarke

写真a

所属(所属キャンパス)

研究所・センター等 自然科学研究教育センター (日吉)

職名

特任准教授(有期)

HP

研究室住所

Keio University, Building 2, room 2204, 4-1-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, Japan

研究室電話番号

+81-45-566-1124

経歴 【 表示 / 非表示

  • 2010年01月
    -
    2010年09月

    University of Pisa, Department of Physics, Galileo Galilei, Postdoc

  • 2010年10月
    -
    2013年08月

    The Hebrew University of Jerusalem, Racah Institute of Physics, Postdoc

  • 2013年09月
    -
    2015年02月

    Nordita - Nordic Institute for Theoretical Physics, Postdoc fellow

  • 2015年03月
    -
    2018年03月

    Institute of Modern Physics, Lanzhou, Associate Professor

  • 2018年04月
    -
    継続中

    Keio University, Department of Physics, and Research and Education Center for Natural Sciences, Project Associate Professor

学歴 【 表示 / 非表示

  • 2001年09月
    -
    2005年03月

    The Technical University of Denmark, Department of Physics

    Denmark, 大学, 卒業, その他

  • 2004年09月
    -
    2006年10月

    The University of Copenhagen, Faculty of Science, The Niels Bohr Institute

    Denmark, 大学, 卒業, 修士

  • 2007年01月
    -
    2010年01月

    University of Pisa, School of Graduate Studies Galileo Galilei, Department of Physics, Enrico Fermi

    Italy, 大学, 卒業, 博士後期

学位 【 表示 / 非表示

  • bach.polyt. (Bachelor's Degree), The Technical University of Denmark, 課程, 2005年03月

  • cand.scient. (Master's Degree), The University of Copenhagen, The Niels Bohr Institute, 論文, 2006年10月

    Beyond standard model physics - New technicolor models

  • PhD, University of Pisa, 論文, 2010年01月

    New vortex types and soliton substructures

 

論文 【 表示 / 非表示

  • Supersymmetry breaking and ghost Goldstino in modulated vacua

    Gudnason S., Nitta M., Sasaki S., Yokokura R.

    Physical Review D (Physical Review D)  99 ( 4 )  2019年02月

    ISSN  24700010

     概要を見る

    © 2019 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP 3 . We discuss spontaneous supersymmetry (SUSY) breaking mechanisms by means of modulated vacua in four-dimensional N=1 supersymmetric field theories. The SUSY breaking due to spatially modulated vacua is extended to the cases of temporally and lightlike modulated vacua, using a higher-derivative model with a chiral superfield, free from the Ostrogradsky instability and the auxiliary field problem. For all the kinds of modulated vacua, SUSY is spontaneously broken and the fermion in the chiral superfield becomes a Goldstino. We further investigate the stability of the modulated vacua. The vacua are (meta)stable if the vacuum energy density is non-negative. However, the vacua become unstable due to the presence of the ghost Goldstino if the vacuum energy density is negative. Finally, we derive the relation between the presence of the ghost Goldstino and the negative vacuum energy density in the modulated vacua using the SUSY algebra.

  • Temporally, spatially, or lightlike modulated vacua in Lorentz invariant theories

    Gudnason S., Nitta M., Sasaki S., Yokokura R.

    Physical Review D (Physical Review D)  99 ( 4 )  2019年02月

    ISSN  24700010

     概要を見る

    © 2019 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP 3 . We study the vacuum structure of a class of Lorentz-invariant field theories where the vacuum expectation values are not constant but are (phase) modulated. The vacua are classified into spatial, temporal, and lightlike modulation types according to the patterns of spontaneous breaking of translational symmetry. The conditions for having temporal or lightlike modulated vacua imply severe constraints on the models. We utilize the notion of generalized Nambu-Goldstone modes which appear in the modulated vacua. Finally, we examine fluctuation modes around these vacua and discuss their dynamics and the absence of ghosts.

  • Integer-squared laws for global vortices in the Born–Infeld wave equations

    Gao Z., Gudnason S., Yang Y.

    Annals of Physics (Annals of Physics)  400   303 - 319 2019年01月

    ISSN  00034916

     概要を見る

    © 2018 Elsevier Inc. A series of quantization identities are established for static vortex solutions governed by the Born–Infeld type actions. These identities are of a universal nature which are indifferent to the details of the models and provide refined descriptions of divergent energetic quantities.

  • Baryonic handles: Skyrmions as open vortex strings on a domain wall

    Gudnason S., Nitta M.

    Physical Review D (Physical Review D)  98 ( 12 )  2018年12月

    ISSN  24700010

     概要を見る

    © 2018 authors. Published by the American Physical Society. We consider the BEC Skyrme model, which is based on a Skyrme-type model with a potential motivated by Bose-Einstein condensates (BECs), and, in particular, we study the Skyrmions in proximity of a domain wall that inhabits the theory. The theory turns out to have a rich flora of Skyrmion solutions that manifest themselves as twisted vortex rings or vortons in the bulk and vortex handles attached to the domain wall. The latter are linked open vortex strings. We further study the interaction between the domain wall and the Skyrmion and between the vortex handles themselves as well as between the vortex handle and the vortex ring in the bulk. We find that the domain wall provides a large binding energy for the solitons and it is energetically preferred to stay as close to the domain wall as possible; other configurations sticking into the bulk are metastable. We find that the most stable 2-Skyrmion is a torus-shaped braided string junction ending on the domain wall, which is produced by a collision of two vortex handles on the wall, but there is also a metastable configuration that is a doubly twisted vortex handle produced by a collision of a vortex handle on the wall and a vortex ring from the bulk.

  • Vibrational modes of Skyrmions

    Gudnason S., Halcrow C.

    Physical Review D (Physical Review D)  98 ( 12 )  2018年12月

    ISSN  24700010

     概要を見る

    © 2018 authors. Published by the American Physical Society. We study the vibrational modes of Skyrmions with baryon numbers one through eight in the standard Skyrme model. The vibrational modes are found in the harmonic approximation around the classical soliton solution and the real parts of the frequencies of the modes are extracted. We further classify the vibrational modes into representations of the symmetries possessed by the Skyrmion solutions. We find that there are approximately 7B low-lying modes for a Skyrmion with baryon number B, in addition to an infinite continuum of scattering modes. This result suggests that the instanton moduli space, which is 8B-dimensional, does not accurately describe the deformation space of Skyrmions as previously conjectured.

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担当授業科目 【 表示 / 非表示

  • 科学と環境Ⅰ

    2019年度