Hiroshi Isono, Department of Physics, Faculty of Science, Chulalongkorn University
A microscopic model for inflation from supersymmetry breaking
Seminar room, Kenkyu honkan 3F
In this talk, I first introduce our recent proposal of a class of small-field inflation models driven by supersymmetry breaking. The inflaton is a superpartner of the goldstino of the supersymmetry breaking, and charged under a gauged U(1) R transformation. The models in this class has a linear superpotential, leading to avoiding the eta problem. Furthermore, the gauged U(1) R invariance makes the pseudo-scalar companion of the inflaton absorbed into the U(1) R gauge field, and also allows for a global minimum with tuneable cosmological constant. I introduce a concrete model in this class as an effective field theory, and propose a generalisation of Fayet-Iliopoulos model in supergravity as a microscopic model leading to this effective theory.
Hisashi Okui, Niigata University
Tomography by neutrino pair beam
Seminar room, Kenkyu honkan 3F, slides (kek.jp only)
Neutrino Tomography is an application of the particle physics to other science. The idea of neutrino tomography is imaging the interior structure of the Earth by using neutrinos. We consider the tomography method using neutrino oscillation. Neutrino oscillation probability is distorted by matter effect, and we reconstruct the matter density distribution that neutrinos passed through from the distortion. We assume the neutrino pair beam which has recently been proposed as an attractive neutrino source. The beam produces a large amount of neutrino and antineutrino pairs from the circulating partially stripped ions and provides the possibility to measure the energy spectrum of oscillation probability very precisely, together with a sufficiently large detector. In addition, we present a method to reconstruct a matter density profile by means of the analytic formula of the oscillation probability in which the matter effect is included perturbatively to the second order.
小林研介, 東大・阪大
[9th KEK joint colloquium] ゆらぎで探る量子液体
Seminar hall 4 go-kan / Room 116 1 go-kan Tokai campus（TV link） 半導体や金属を微細加工して作られる微小な固体素子をメゾスコピック系と呼ぶ。
半導体や金属を微細加工して作られる微小な固体素子をメゾスコピック系と呼ぶ。
その最大の特長は、量子効果が本質的なスケールにおいて、磁場や電場などの外場を利用することで、制御性の高い精密な実験が可能となる点にある。
たとえば、電子干渉計や人工原子等で発現するコヒーレンス・スピン・多体効果に依存する伝導の研究は、物性物理学の発展に大きな貢献を果たしてきた。
これまで、メゾスコピック系における実験研究の多くは、系の電気伝導度測定を主体とするものであった。しかし、近年、非平衡状態の動的な情報を得る手段として、電流ゆらぎ（電流雑音）測定が大きな関心を集めている[１]。本講演では、まず、メゾスコピック系と電流ゆらぎについて紹介する。さらに、近藤効果によって、人工原子に形成された量子液体のゆらぎについて、議論する[２−５]。
[１]K. Kobayashi, Proc. Jpn. Acad., Ser. B 92, 204 (2016).
[２]Y. Yamauchi et al., Phys. Rev. Lett. 106, 176601 (2011).
[３]M. Ferrier et al., Nature Phys. 12, 230 (2016).
[４] M. Ferrier et al., Phys. Rev. Lett. 118, 196803 (2017).
[５]T. Hata et al., Phys. Rev. Lett. 121, 247703 (2018).
岡本亮, 京都大学
量子系の時間発展と弱値
Meeting room 3, Kenkyu honkan 1F
量子系では，「観測」がその後の量子状態の時間発展に大きな影響を及ぼす．例えば，ある時刻に，光子の位置の射影測定を行った場合，その後の光子の位置の時間発展は，測定を行わなかった場合と大きく異なってしまう．同様に，光子の位置の射影測定を行った後，運動量の射影測定を行ったとしても，位置測定以前の運動量の正確な情報を得ることはできない．従って，射影測定を用いて，光子が辿る軌跡を問うこと無意味である．一方，射影測定ではなく，「弱測定」と呼ばれる測定手法，および弱測定結果から得られる「弱値」を用いると，この問いに答えることができる．例えば，トロント大学の研究グループは，2重スリットの実験において，弱測定を用いることで，光子の軌跡を記録することに成功している．また，位置と運動量のような，非可換な観測量の同時測定が，連続的な弱測定によって実現されている．これにより，パラドキシカルな弱値の間の関係性といった従来アクセスできなかった情報を得ることが可能になっている．本講演では，時間発展する量子系の弱値について，光子を用いた実験を軸に概観するとともに，最近の我々の研究結果について紹介する．
Yusuke Yamada, Research center for the early universe (RESCEU), University of Tokyo
Nonlinear realization in supergravity and its application
Meeting room 3, Kenkyu honkan 1F
Spontaneously broken supersymmetry plays important roles in supergravity model buildings. Below the supersymmetry breaking scale, the effective theory is well described by nonlinear realizations of supergravity. We show two applications of nonlinearly realized supergravity: One is the effective action of anti-D3 brane in KKLT background. The KKLT model is well known as the string realization of de Sitter vacua. The anti-D3 brane plays an important role in uplifting the vacuum. We show that the world volume fields on anti-D3 brane and their couplings are described in terms of the constrained superfields (nonlinear realizations). Secondly, we show that the nonlinear realization is useful to realize non-supersymmetric models within supergravity. As an example, we show the embedding of the Horndeski model into supergravity, which describes the most general ghost-free scalar-tensor system.
Takumi Doi, RIKEN Nishina Center for Accelerator-Based Science
Nuclear Physics from Lattice QCD
Meeting Room 1, Kenkyu honkan 1F
One of the most fundamental questions in nuclear physics is how nuclear physics itself emerges from the underlying theory, quantum chromodynamics (QCD), and the determination of baryon forces from QCD plays a crucial role to answer this question. In this talk, I review the first-principles lattice QCD calculation of baryon forces as well as general hadron-hadron interactions. I introduce a novel theoretical framework, HAL QCD method, and present the latest lattice QCD results, in particular, those obtained near the physical point. The physical implications for exotic dibaryons, equation of state of high dense matter and the structure of neutron stars are also discussed and future prospects will be given.
Sota Nakajima, Osaka City University
Exponentially suppressed cosmological constant with enhanced gauge symmetry in heterotic interpolating models
Meeting room 1, Kenkyu honkan 1F
An interpolating model is a (D－ d)-dimensional string model that continuously relates two D-dimensional string models. A few nine-dimensional interpolating models with two parameters are constructed and the massless spectra are studied by considering compactification of heterotic strings on a twisted circle with Wilson line. It is found that there are some conditions between radius R and Wilson line A under which the gauge symmetry is enhanced. In particular, when the gauge symmetry is enhanced to SO(18) \times SO(14), the cosmological constant is exponentially suppressed. We also construct a non-supersymmetric string model which is tachyon-free in all regions of moduli space and whose gauge symmetry involves E_8. This talk will be based on the work with H. Itoyama, arXiv: 1905.10745.
小川和久, 北海道大学
プローブを用いない弱値の直接測定法
Seminar room, Kenkyu honkan 3F
事前・事後選択されたシステム（事前・事後選択系）における弱い値は、典型的には弱測定によって測定され、そこではプローブ系は被測定系と弱い相互作用をする。しかし弱測定では、プローブ系として被測定系の他に追加の自由度を準備する必要性があるため、弱値測定のための実験系は一般に複雑になる。本研究では、事前・事後選択系がほとんど乱されないという従来の弱測定が持つ条件を保ちながら、プローブを用いずに弱値を直接測定する方法を提案する。この方法では、事前選択と事後選択の間に小さな変換が与えた時に、選択後の確率振幅の変化に小さな変換の微分の弱値が現れる。この方法は基本的に弱値を測定する全ての実験に適用することができ、弱値測定のための実験系を単純化することができる。
Shohei Saga, JSPS Fellow, Yukawa Institute for Theoretical Physics
The vector mode in the observational cosmology
Meeting room 1, Kenkyu honkan 1F In the context of the cosmological perturbation theory, perturbations can be decomposed into the scalar, vector, and tensor modes. Current observations strongly support only the scalar mode. It is known that the vector mode does not arise from the linear perturbation theory in the standard cosmology.
In the context of the cosmological perturbation theory, perturbations can be decomposed into the scalar, vector, and tensor modes. Current observations strongly support only the scalar mode. It is known that the vector mode does not arise from the linear perturbation theory in the standard cosmology.
In this talk, I will introduce the second-order vector mode, which is inevitably generated in the standard cosmology. I also show the way to observe the vector-mode signature. Finally, I will mention a role of the second-order vector mode in observational cosmology.
Kouichi Hagino, Department of Physics, Graduate School of Science, Tohoku University
Perspectives on nuclear reaction theory and superheavy elements
Meeting room 1, Kenkyu honkan 1F, slides (kek.jp only)
