Daisuke Yamauchi, RESCUE
Open inflation in the Landscape
Meeting Room 1, Kenkyu Honkan 1F
Vaccum decay is one of the most intriguing phenomena in field theory. It occurs via the nucleation of a vacuum bubble by quantum tunneling from a metastable vacuum. When gravity is included, the tunneling is mediated by an O(4)-symmetric solution of Euclidean Einstein-scalar field equations. Though there is no direct evidence that our part of the universe is inside one of those nucleated bubbles, there are theoretical reasons to believes that it may be actually the case. In this talk I discuss the possible observational signatures of the quantum tunneling. I specifically focus on two cases: the signatures in large angle CMB power spectrum, and spatially localized anisotropies.
伊藤憲二, The Graduate University for Advanced Studies
日本における量子物理学研究の始まりと量子力学の解釈
Room 322, Kenkyu Honkan 3F
日本の物理学は量子力学の導入を契機に、１９３０年代に国際的な研究水準に達した。 本セミナーでは、 この時期の日本の物理学研究がどのように変化をし、日本で量子物理学の研究が始まったのかについてお話する。 とくに、その過程で、量子力学の概念的な側面、不確定性関係、相補性、波動関数の確率解釈等に対して、 日本の物理学者やその他の知識人がどのように反応し、どのような議論が生じたのかについて述べる。
Shinji Shimasaki, Kyoto U
[Strings and Fields Group Seminar] Exact results of theories with SU(2|4) symmetry and gauge/gravity correspondence
Meeting room 1, Kenkyu honkan 1F
We study the theories with SU(2|4) symmetry which consist of the plane wave matrix model (PWMM), super Yang-Mills theory (SYM) on RxS^2 and SYM on RxS^3/Z_k. The last two theories can be realized as theories around particular vacua in PWMM, through the commutative limit of fuzzy sphere and Taylor’s T-duality. We apply the localization method to PWMM to reduce the partition function and the expectation values of a class of supersymmetric operators to matrix integrals. By taking the commutative limit and performing the T-duality, we then obtain the matrix integrals for SYM on RxS^2 and SYM on RxS^3/Z_k. We also discuss some applications of our results to gauge/gravity correspondence and little string theory on RxS^5.
Natsumi Nagata, Nagoya University
Minimal SUSY SU(5) GUT in the high-scale SUSY scenario
Meeting Room 1, Kenkyu Honkan 1F
We revisit the minimal supersymmetric SU(5) grand unified theory (SUSY SU(5) GUT) in the high-scale SUSY scenario. Although the model has been believed to be excluded due to the too short lifetime of proton, we have found that it is possible to evade the experimental constraints on the proton decay rate if the supersymmetric particles have masses much heavier than the electroweak scale. With such heavy sfermions, the 126GeV Higgs boson is naturally explained, while they do not spoil the gauge coupling unification and the existence of dark matter candidates. Since the resultant proton lifetime lies in the regions which may be reached in the future experiments, proton decay searches may give us a chance to verify the scenario as well as the supersymmetric grand unified models.
Kohta Murase, Hubble Fellow, Institute for Advanced Study
Cascade Gamma rays: Revealing the Obscured Universe
Seminar room, Kenkyu honkan 3F
Recent observations of the isotropic diffuse gamma-ray background by Fermi allow us to get more insight into distant very-high-energy (VHE) and ultra-high-energy (UHE) gamma-ray emitters, including cosmic-ray sources. The Fermi data are well above expectations for an attenuated power law, which may suggest a possible VHE Excess. We consider its origin and show the importance of intergalactic cascades induced by gamma-rays and/or cosmic rays (CRs) for astrophysical scenarios. The relevance of the cascades is also motivated by possible VHE excesses found in some TeV blazars, which requires very hard intrinsic spectra. They are also important to constrain the UHECR origin and dark matter, as well as neutrino observations by IceCube. We may discuss possibilities of transient cascade gamma-ray sources.
Maxim Pospelov, U. of Victoria/Perimeter
EDMs and LFV in the LHC and post-LHC era
Meeting Room 1, Kenkyu Honkan 1F
Searches EDMs and LFV have a unique capability of probing the energy scales, currently unaccessible in direct collider experiments. After the review of the EDMs, I will put these searches in the modern context and will discuss: 1. How the CP and flavor properties of the Higgs-like resonance are constrained 2. What the naturalness expectations are for the EDMs, if one assumes sub-PeV SUSY.
Kenji Toma, Osaka Univ
Efficient Acceleration of Relativistic Magnetohydrodynamic Jets
Meeting Room 1, Kenkyu Honkan 1F
Collimated outflows (or jets) with relativistic speeds are driven in various celestial objects. The origin of relativistic jets are thought to be black holes with their accretion flows, although the detailed mechanism remains unknown. A widely discussed model is that rotational energy of the accretion flow is magnetohydrodynamically converted into the outflow energy in analogy of pulsar winds. One of the major problems for this model is how Poynting flux can be efficiently transferred to particle kinetic energy flux. Recently some numerical simulations of global structure of steady magnetohydrodynamic jets have been significantly developed, but they have not succeeded in reproducing the energy conversion as efficient as suggested by observations. We focus on the motion along a magnetic field line and show some examples of 2-dimensional field configuration for which the energy conversion is efficient enough, also discussing the conditions required for the external boundary of the jet.
Jyotirmoy Bhattacharya, Kavli IPMU, Univ. of Tokyo
Equilibrium partition functions and actions for hydrodynamics
Meeting Room 1, Kenkyu-Honkan 1F
At first, we shall study the thermal partition function of quantum field theories on arbitrary stationary background spacetime, and with arbitrary stationary background gauge fields, in the long wavelength expansion. We shall demonstrate that the equations of relativistic hydrodynamics are significantly constrained by the requirement of consistency with any partition function. In specific examples, at low orders in the derivative expansion, we shall demonstrate that these constraints coincide precisely with the equalities between hydrodynamic transport coefficients that follow from the local form of the second law of thermodynamics. We shall then go on to construct non-trivial classical action for second order non-dissipative hydrodynamics involving pure energy-momentum transport. Comparison of our results with non-dissipative hydrodynamics that follows from entropy current analysis, reveals the existence of additional constrains, when the effective theory of hydrodynamics follows from an action principle.
Arhrib Abdesslam, Abdelmalek Essadi U.
Diphoton excess in type II seesaw Model
Meeting Room 1, Kenkyu Honkan 1F
In this talk, the general renormalizable Higgs potential of the type II seesaw model will be introduced. A detail study of its main dynamical constraints such as boundedness from below and perturbative unitarity will presented. Then, I will discuss how the model can account for the two photon excess found by CMS and ATLAS.
森越文明, NTT物性科学基礎研究所
量子論の存在論的モデルにおける非局所性
Room 322, Kenkyu Honkan 3F
