Yoshinori Matsuo, University of Crete
Hyperscaling-violating Lifshitz hydrodynamics from black-holes
Meeting Room 322, Kenkyu Honkan 3F
Non-equilibrium black hole horizons are considered in scaling theories with generic Lifshitz invariance and an unbroken U(1) symmetry. There is also a special form of hyperscaling violation associated with a non-trivial conduction exponent. The boundary stress tensor is computed and renormalized, and the associated hydrodynamic equations are derived. Upon a non-trivial redefinition of boundary sources associated with the U(1) gauge field, the equations are mapped to the standard non-relativistic hydrodynamics equations coupled to a mass current and an external Newton potentials. The shear viscosity to entropy ratio is the same as in the relativistic case.
Rainer Sommer, DESY
The strong coupling from lattice QCD
Room 244, 4 go-kan 2F
After an introduction into what the strong coupling is, and how QCD discretized on a space-time lattice works, I discuss which methods are available to use lattice QCD in order to extract the strong coupling from experimental information. I then briefly review the status of these computations including the world average of the FLAG2 review and more recent developments.
Satoshi Ohya, Institute Quantum Science, Nihon University
BPS Monopole in the Space of Boundary Conditions
Seminar room, Kenkyu honkan 3F
The space of all possible boundary conditions that respect self-adjointness of Hamiltonian operator is known to be given by the group manifold U(2) in one-dimensional quantum mechanics. In this talk we study non-Abelian Berry’s connections in the space of boundary conditions in a simple quantum mechanical system: We consider a system for a free spinless particle on a circle with two point-like interactions described by the U(2) ¥times U(2) family of boundary conditions. We show that, for a certain SU(2) ¥subset U(2) ¥times U(2) subfamily of boundary conditions, all the energy levels become doubly-degenerate thanks to the so-called higher-derivative supersymmetry, and non-Abelian Berry’s connection in the ground-state sector is given by the Bogomolny-Prasad-Sommerfield (BPS) monopole of SU(2) Yang-Mills-Higgs theory. We also show that, in the ground-state sector of this quantum mechanical model, matrix elements of position operator give the adjoint Higgs field that satisfies the BPS equation. It is also discussed that Berry’s connections in the excited-state sectors are given by non-BPS ‘t Hooft-Polyakov monopoles.
Kai Schmitz, IPMU
Leptogenesis during Axion Relaxation after Inflation
Meeting Room 322, Kenkyu Honkan 3F
In this talk, I present a novel and minimal alternative to thermal leptogenesis, which builds upon the assumption that the electroweak gauge bosons are coupled to an axion-like scalar field, as it is, for instance, the case in certain string compactifications. The motion of this axion-like field after the end of inflation generates an effective chemical potential for leptons and antileptons, which, in the presence of lepton number-violating scatterings mediated by heavy Majorana neutrinos, provides an opportunity for baryogenesis via leptogenesis. In contrast to thermal leptogenesis, the final baryon asymmetry turns out to be insensitive to the masses and CP-violating phases in the heavy neutrino sector. Moreover, the proposed scenario requires a reheating temperature of at least O(10^12) GeV and it is, in particular, consistent with heavy neutrino masses close the scale of grand unification. This talk is based on recent work (Phys. Rev. Lett. 115 (2015) 1, 011302, 1412.2043 [hep-ph]) in collaboration with Alexander Kusenko from UCLA and Tsutomu T. Yanagida from Kavli IPMU.”
Emi Kou, Orsay, Laboratoire de l'Accélérateur Linéaire
B2TiP and highlight of Belle II physics
Meeting room 1, Kenkyu honkan 1F
For this occasion, I would like to present the activity of the Belle II physics working group, the B2TiP (Belle II Theory interface Platform) and the highlight of the current discussions in this working group. It will be an informal seminar targeted to experts and non-experts of B physics who are interested in B2TiP activity and want to know “what will be the main interests of Belle II physics?”.
Sayantan Sharma, Brookhaven
The origin of axial anomaly and the high temperature phase of QCD
Meeting Room 1, Kenkyu Honkan 1F
The axial U_A(1) though an anomalous symmetry is believed to affect the order of the chiral phase transition in QCD with two light quark flavours. In this talk I discuss about our study of the axial anomaly in finite temperature QCD using first principles lattice gauge theory technique. We use chiral overlap fermions to probe the underlying topology of dynamical QCD configurations with two light quark flavours generated with Highly improved staggered quarks. From the eigenvalue spectrum of the overlap operator we find no evidence of effective restoration of U_A(1) near the chiral transition temperature $T_c$. A pile up of the near-zero eigenmodes is observed to persist even at $1.5 T_c$ which is primarily responsible for its breaking . These eigenmodes are localized unlike those in the bulk, with a mobility edge similar to a Mott–Anderson like system. We find evidence in support of a dilute gas of instantons at the highest temperature studied, as the microscopic origin of the breaking of U_A(1) symmetry.
Ryosuke Hirai, Waseda
Ejecta-Companion Interaction in Massive Star Binaries
Meeting Room 1, Kenkyu Honkan 1F
Recent surveys show that almost all massive stars are born in binary systems. From the fact that these massive stars are the progenitors for core-collapse supernovae, the majority of these events should be occuring in binaries. When a star explodes in a binary, the companion may be affected by the supernova ejecta, possibly changing the further evolution of the binary. In this talk I will introduce results of hydrodynamical simulations of supernova ejecta hitting a star in massive binaries. We focus on the mass removed and its dependences on parameters. I will also show its application on a real supernova, iPTF13bvn, and our prediction on the possible observational features of the companion star.
Mariko Kikuchi, Toyama University
ヒッグス結合定数の輻射補正の研究と将来実験の精密測定を用いたヒッグスセクターの構造決定
Meeting room 1, Kenkyu honkan 1F 新物理学模型におけるヒッグス結合定数の標準模型からのずれのパターンには 模型の特徴が表れる。よって、様々な模型においてそのズレのパターンを研究 することは模型の識別のために有効である。特に、高輝度LHC実験やILC実験 ではヒッグス結合定数の精密測定が期待されており、ヒッグス結合定数を輻射 補正の効果を含めて精密に計算することが必要である。 本セミナーでは、ヒッグス結合の将来精密測定を用いてヒッグスセクターを解明 し新物理学を決定することを目的に、様々な拡張ヒッグス模型におけるゲージ結合、 湯川結合、ヒッグス自己結合に対する輻射補正を系統的に計算した結果を示す。 そして、各模型ごとの結合定数のズレのパターンを１ループレベルで求め、将来の 精密測定でその特徴的なズレのパターンを観測することによる模型の識別・同定 可能性を示す。さらに、将来の精密測定と輻射補正を含めたヒッグス結合定数の 理論予言値の比較によって、模型の内部パラメーターの情報を引き出せる可能性 を議論する。
新物理学模型におけるヒッグス結合定数の標準模型からのずれのパターンには 模型の特徴が表れる。よって、様々な模型においてそのズレのパターンを研究 することは模型の識別のために有効である。特に、高輝度LHC実験やILC実験 ではヒッグス結合定数の精密測定が期待されており、ヒッグス結合定数を輻射 補正の効果を含めて精密に計算することが必要である。 本セミナーでは、ヒッグス結合の将来精密測定を用いてヒッグスセクターを解明 し新物理学を決定することを目的に、様々な拡張ヒッグス模型におけるゲージ結合、 湯川結合、ヒッグス自己結合に対する輻射補正を系統的に計算した結果を示す。 そして、各模型ごとの結合定数のズレのパターンを１ループレベルで求め、将来の 精密測定でその特徴的なズレのパターンを観測することによる模型の識別・同定 可能性を示す。さらに、将来の精密測定と輻射補正を含めたヒッグス結合定数の 理論予言値の比較によって、模型の内部パラメーターの情報を引き出せる可能性 を議論する。
（References)
S. Kanemura, M. Kikuchi and K. Yagyu, Nucl. Phys. B896, 80 (2015)
S. Kanemura, M. Kikuchi and K. Yagyu, Phys. Lett. B731, 27 (2014)
S. Kanemura, M. Kikuchi and K. Yagyu, Phys. Rev. D88, 015020 (2013)
M. Aoki, S. Kanemura, M. Kikuchi and K. Yagyu, Phys. Rev. D87, 1, 015012 (2013)
Hiroyuki Ishida, Shimane University
Higgs inflation in a singlet extension of the standard model
Room 345, 4 go-kan 3F
Inflation is the most plausible mechanism to resolve several cosmological problems in the early universe. Higgs inflation is clearly the most economical possibility. The original Higgs inflation, however, requires quite a huge coupling between the Higgs field and the gravity, named the non-minimal coupling. We propose a model with a right-handed neutrino and a Z_2 odd real scalar field, which can account for tiny neutrino masses and the dark matter. We show that our model gives the non-minimal coupling of around 10, consistent with the recent Planck observation. Furthermore, we show that the masses of the right-handed neutrino and the dark matter are not seriously constrained by the observed value of the tensor-to-scalar ratio.
Shogo Tanimura, Graduate School of Information Science, Nagoya University
量子測定理論の数学的定式化・量子論と 確率の諸解釈
Seminar Room, Kenkyu Honkan 3F 量子測定理論は，素朴な「波束の収縮」仮説に訴えることなく，量子系の測定における確率と状態変化を記述する理論である．このセミナーでは、 量子測定理 論の基本概念である POVM (probability-operator valued measure), CP map (completely positive map), instrument と，間接測定モデル表現を解説する． また，量子論の解釈に関しては諸説あるが，波動関数の確率解釈を言うにしても，確率自体の解釈に関しても諸説ある．確率の解釈を吟味しないことには， 量子論の解釈を分析することもできないと思われるので，確率の解釈に関する議論を整理したいと思う．ちなみに，私は，波動関数や状態ベクトルやヒルベルト空間は，ミクロ系の内に宿った実体のようなものと捉えるべきではなく，ミク ロ系とマクロ系の間の橋渡し・窓口のようなものとみなすのがよいと考えている．そういう意味で，代数的量子論におけるヒルベルト空間のGNS構成が適切な数理だと考えている．
