Carsten Rott, Ohio State University
Closing in on Dark Matter with Neutrino Telescopes
Meeting room 3, Kenkyu honkan 1F
Unraveling the mysterious nature of dark matter is one of the most exciting scientific goals of this decade. While there is overwhelming evidence for its existence, its properties remain literally in the dark. New approaches in the search for dark matter might finally shed light on its properties and distribution in our Galaxy. Neutrino telescopes offer exciting opportunities for the detection of neutrinos produced as part of dark matter self-annihilations or decays. Using data collected during the construction period of the giga-ton sized IceCube detector, I will present a new analysis that searched for a neutrino anisotropy from the Galactic dark matter halo. This search is complementary to searches performed with gamma-ray telescopes and capable to test dark matter models motivated by the observed lepton excess by PAMELA. I will further discuss results from searches looking at the Galactic Center and dwarf spheroidal galaxies, which are expected to be dark matter dominated. Besides these searches that can constrain the dark matter self-annihilation cross section, I will discuss prospect and methods in the search for dark matter captured by the Sun. These Solar WIMP searches offer complementary ways to direct detection experiments to probe the dark matter nucleon scattering cross sections. The talk will also cover a first look at results obtained with the low-energy extension of IceCube, Deep Core, which is taking data since June 2010. Future upgrades that offers exciting opportunities for dark matter searches down to candidate masses in the GeV range, will be discussed as part of an outlook.
Antonio Enea Romano, National Taiwan Univeristy
Corrections to the apparent value of the cosmological constant due to local inhomogeneities
Seminar room, Kenkyu honkan 3F
Supernovae observations strongly support the presence of a cosmological constant, but its value, which we will call apparent, is normally determined assuming that the Universe can be accurately described by a homogeneous model. Even in the presence of a cosmological constant we cannot exclude nevertheless the presence of a small local inhomogeneity which could affect the apparent value of the cosmological constant. Neglecting the presence of the inhomogeneity can in fact introduce a systematic misinterpretation of cosmological data, leading to the distinction between an apparent and true value of the cosmological constant. Modeling the local inhomogeneity with a $¥Lambda LTB$ solution we compute the relation between the apparent and true value of the cosmological constant. Contrary to previous attempts to fit data using large void models our approach is quite general. The correction to the apparent value of the cosmological constant is in fact present for local inhomogeneity of any size, and should always be taken appropriately into account both theoretically and observationally.
Danny Marfatia, Kansas Univeristy
Isospin-Violating Dark Matter
Meeting room 1, Kenkyu honkan 1F
Searches for dark matter scattering off nuclei are typically compared assuming that the dark matter’s spin-independent couplings are identical for protons and neutrons. This assumption is neither without consequence nor well motivated. We consider isospin-violating dark matter with one extra parameter, the ratio of neutron to proton couplings. For a single choice of this ratio, the DAMA and CoGeNT signals are consistent with each other and with XENON constraints, and unambiguously predict a signal at CRESST.
Tsubasa Ichikawa, Kinki U
系統的なエラーに耐性のあるユニタリ操作の設計
Seminar room, Kenkyu honkan 3F
量子情報処理では、系の正確な操作が不可欠である。一方、実際の実験環境ではノイズやエラーの影響により、実際に行った操作が所望の操作からずれてしまうことが一般的である。従って、所望の操作を実装するにあたっては、上手い工夫をして「ずれ」が少なくなるようにすることが望ましい。 本講演では、上述のずれの少ない量子操作をどのように設計すればよいかについて紹介する。近年の進展を概説した後に、二準位系に対する最近の我々のグループの取り組みについて述べる。
Kousuke Sumiyoshi, Numazu College of Technology / KEK
Progress of EOS tables for core-collapse supernovae & its applications to explosion dynamics and neutrino signals
Seminar room, Kenkyu honkan 3F
I would like to talk on the recent development of the EOS tables for core-collapse supernovae and their influence on the dynamics and the signal of neutrino bursts. I would like to describe the role of the equation of state in the neutrino-radiation hydrodynamics for supernova explosion. Some topics I try to cover include the mixture of light elements in supernova cores and the neutrino emission from the black hole formation.
Masahiro Ibe, ICRR
Recent Model Buildings of Gauge Mediation
Meeting room 1, Kenkyu honkan 1F
The models with gauge mediation are quite attractive to realize phenomenologically viable supersymmetric standard model. From the cosmological point of view, the models with the very light gravitino with a mass in the eV range is also motivated since it does not cause any cosmological problems. The models with such a light gravitino mass is, however, known to difficult to be realized. In this talk, I explain our recent models which realize such a very light gravitino mass. I also discuss a separate topic in gauge mediation, the lightest Higgs boson mass in gauge mediation. In the MSSM with gauge mediation, the Higgs boson mass is usually predicted at the lower edge of the experimental bound. We show however, the Higgs boson mass can be much enhanced even if we do not extend the models.
Naoki Yamamoto, Keio University
量子フィードバック制御理論の基礎
Seminar room, Kenkyu honkan 3F
量子系を制御する方策として、系を時間連続的に測定し、測定結果に基づいた操作を行う「フィードバック制御」によるものが容易に思いつく。しかし、古典系の場合と異なり、量子系については例えば非可換物理量を同時に測定することができないなど、測定に本質的な制限が課せられる。また、制御を考慮するにあたって、測定のバックアクションも見逃せない問題となる。本講演では、このような問題をクリアし新しい量子情報操作プロトコルを提供する「量子フィードバック制御理論」の基礎を説明する。とくに、この理論の実際的恩恵として、エンタングルの確定的生成法などについて説明する。
Yosuke Imamura, Tokyo Institute of Technology
Exact results in 3d gauge theories and M-theory
Meeting room 1, Kenkyu honkan 1F
Recently some exact results for gauge theories were obtained by using localizatuion. I will review a derivation of the superconformal index for 3d gauge theories, and apply it to Chern-Simons theories dual to M-theory in AdS_4xM_7. The obtained indices are consistent with the symmetry enhancement in gauge theory predicted by AdS/CFT.
Tatsu Takeuchi, Virginia Tech U
Ratchet Model of Baryogenesis
Meeting room 1, Kenkyu honkan 1F
Many models of baryogenesis, such as the Affleck-Dine model, utilize the coherent time-evolution of a baryon-number bearing scalar field to generate baryon-number. This this talk. I point out the resemblance of the problem to the theory of biological motors in which biassed motion is driven by ATP hydrolysis. I argue that a similar mechanism may be implementable in the particle theory context, and lead to interesting model building possibilities.
Hirotaka Yoshino, KEK
[理論宇宙物理グループセミナー] 粒子衝突における重力波放出の摂動解析：レビュー
Meeting room 3, Kenkyu honkan 1F 大きな余剰次元があるシナリオでは加速器においてブラックホールが形成される可能性があるが、その際に放出される重力波がどの程度のエネルギーを持ち去るかを計算することは重要な課題である。ひとつのアプローチは、数値相対論でシミュレーションすることであるが、技術的困難によりあまり進んでいない。一方で、重力波の一部については摂動の方法で解析することが可能である。これは４次元の場合には D’Eath and Payne によってなされたが、最近Herdeiro らによって高次元の場合に拡張された。今回はこの論文の概要と結果を紹介する。
