118598825
A measurement of the cosmic microwave background B-mode polarization power spectrum at sub-degree scales with POLARBEAR
We report a measurement of the B-mode polarization power spectrum in the cosmic microwave background (CMB) using the POLARBEAR experiment in Chile. The faint B-mode polarization signature carries information about the universe's entire history of gravitational structure formation, and the cosmic inflation that may have occurred in the very early universe. Our measurement covers the angular multipole range 500 < ? < 2100 and is based on observations of an effective sky area of 25? with 3.'5 resolution at 150?GHz. On these angular scales, gravitational lensing of the CMB by intervening structure in the universe is expected to be the dominant source of B-mode polarization. Including both systematic and statistical uncertainties, the hypothesis of no B-mode polarization power from gravitational lensing is rejected at 97.2% confidence. The band powers are consistent with the standard cosmological model. Fitting a single lensing amplitude parameter ABB to the measured band powers, , where ABB = 1 is the fiducial WMAP-9 ?CDM value. In this expression, stat refers to the statistical uncertainty, sys to the systematic uncertainty associated with possible biases from the instrument and astrophysical foregrounds, and multi to the calibration uncertainties that have a multiplicative effect on the measured amplitude ABB .
118412548
Mission Design of LiteBIRD
LiteBIRD is a next-generation satellite mission to measure the polarization of the cosmic microwave background (CMB) radiation. On large angular scales the B-mode polarization of the CMB carries the imprint of primordial gravitational waves, and its precise measurement would provide a powerful probe of the epoch of inflation. The goal of LiteBIRD is to achieve a measurement of the characterizing tensor to scalar ratio $$r$$r to an uncertainty of $$\delta r=0.001$$δr=0.001. In order to achieve this goal we will employ a kilo-pixel superconducting detector array on a cryogenically cooled sub-Kelvin focal plane with an optical system at a temperature of 4 K. We are currently considering two detector array options; transition edge sensor (TES) bolometers and microwave kinetic inductance detectors. In this paper we give an overview of LiteBIRD and describe a TES-based polarimeter designed to achieve the target sensitivity of 2 $$\upmu $$μK arcmin over the frequency range 50–320 GHz.
124042682
Lorentz-covariant four-vector formalism for two-measure theory
In the conventional two-measure theory, the scalar density function $\ensuremath{\Phi}$ is taken to be $\ensuremath{\Phi}\ensuremath{\equiv}{ϵ}^{\ensuremath{\mu}\ensuremath{\nu}\ensuremath{\rho}\ensuremath{\sigma}}{ϵ}_{abcd}({\ensuremath{\partial}}_{\ensuremath{\mu}}{\ensuremath{\varphi}}^{a})({\ensuremath{\partial}}_{\ensuremath{\nu}}{\ensuremath{\varphi}}^{b})({\ensuremath{\partial}}_{\ensuremath{\rho}}{\ensuremath{\varphi}}^{c})({\ensuremath{\partial}}_{\ensuremath{\sigma}}{\ensuremath{\varphi}}^{d})$, where the indices $a,b,c,d=1$, 2, 3, 4 are internal-space indices. It is more natural to replace the four scalars ${\ensuremath{\varphi}}^{a}$ by a Lorentz-covariant four-vector ${\ensuremath{\varphi}}^{m}$ with a local Lorentz index $m=(0)$, (1), (2), (3). We entertain this possibility, and show that the newly proposed Lagrangian respects not only Lorentz covariance, but also global-scale invariance. The crucial equation ${\ensuremath{\partial}}_{\ensuremath{\mu}}L=0$ in the conventional two-measure theory also arises in our new formulation, as the ${\ensuremath{\varphi}}^{m}$-field equation.
123621972
N=(2,0) SUPERSTRING AS THE UNDERLYING THEORY OF SELF-DUAL YANG-MILLS THEORY
We study the condition of vanishing of beta-functions in the (2,0) heterotic σ-model coupled to background Yang-Mills field. The condition of vanishing β-functions restricts the background Yang-Mills fields to be self-dual in the critical real four-dimensional target space-time with the signature (2,2). This supports the suggestion of Ooguri and Vafa that the N=(2,0) heterotic superstring underlies the four-dimensional self-dual Yang-Mills theories and that the (2,0) heterotic superstring theory is, indeed, the fundamental underlying theory of all lower-dimensional (bosonic) soluble systems. It is shown that N=(2,0) heterotic σ-models in superspace couple precisely to the prepotential of the J-formulation of SDYM theory.
121664450
String loop effect on the BRST charge
Abstract An effective BRST charge Q BRST which incorporates the string one-loop corrections is presented for the closed basonic string in an arbitrary background. The effective σ-model action which leads to such a Q BRST is obtained and some consequences are discussed.
50171016
Unimodular Supergravity
We present the locally supersymmetric formulation of unimodular gravity theory in D (1 ≤ D ≤ 11) dimensions, namely supergravity theory with the metric tensor whose determinant is constrained to be unity. In such a formulation, the usual fine-tuning of cosmological constant is no longer needed, but its value is understood as an initial condition. Moreover, the zero-ness of the cosmological constant is concluded as the most probable configuration, based on the effective vacuum functional. We also show that the closure of supersymmetry gauge algebra is consistent with the unimodular condition on the metric.
50204645
Supermembrane with U(1)-Gauging
We study the effect of a Killing vector for the isometry for the compactification of eleven-dimensional supermembrane into ten-dimensional superstring. We first see that all the effects by the Killing vector are cancelled by themselves, when we limit ourselves to target superspace, reflecting the uniqueness of eleven-dimensional super-gravity. However, a fundamental U(1) gauge field can be coupled to a super Killing vector in supermembrane action on eleven-dimensional superspace background with new physical effects on its world-volume, as usual in gauged sigma-models. Our total supermembrane action has fermionic κ-invariance, composite Λ-gauge, and local U(1) gauge invariance. As a technical but also important tool, we use teleparallel superspace with no manifest local Lorentz covariance, as the natural and consistent background for the compactification of supermembrane.