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Large gauge transformation, soft theorem, and Infrared divergence in inflationary spacetime

Abstract It is widely known that the primordial curvature perturbation ζ has several universal properties in the infrared (IR) such as the soft theorem, which is also known as the consistency relation, and the conservation in time. They are valid in rather general single clock models of inflation. It has been argued that these universal properties are deeply related to the large...

Determination of the freshwater origin of Coastal Oyashio Water using humic-like fluorescence in dissolved organic matter

Coastal Oyashio Water (COW), defined as a water mass with a temperature lower than 2 °C and a salinity lower than 33.0, is distributed in the North Pacific Ocean off southeastern Hokkaido, Japan, from winter to spring. COW is rich in macronutrients and dissolved iron and is thus considered to affect the spring phytoplankton blooms in the Oyashio region. Although river water and...

Vacuum state of the Dirac field in de Sitter space and entanglement entropy

Abstract We compute the entanglement entropy of a free massive Dirac field between two causally disconnected open charts in de Sitter space. We first derive the Bunch-Davies vacuum mode functions of the Dirac field. We find there exists no supercurvature mode for the Dirac field. We then give the Bogoliubov transformation between the Bunch-Davies vacuum and the open chart vacua...

First Evidence of Coherent Bands of Strong Turbulent Layers Associated with High-Wavenumber Internal-Wave Shear in the Upstream Kuroshio

Nagai Daisuke Hasegawa Takahiro Tanaka Hirohiko Nakamura Eisuke Tsutsumi Ryuichiro Inoue ToruYamashiro OPEN The upstream Kuroshio flows through Okinawa Trough and the Tokara island chain, the region

Synergy between ground- and space-based gravitational-wave detectors for estimation of binary coalescence parameters

We study the advantages of the coexistence of future ground- and space-based gravitational-wave detectors in estimating the parameters of a binary coalescence. Space measurements will act as a precursor to ground measurements. Also, since space measurements will provide much better localization information on the source, they will aid electromagnetic follow-up of the source and...

Estimate of the radius responsible for quasinormal modes in the extreme Kerr limit and asymptotic behavior of the Sasaki–Nakamura transformation

The Sasaki–Nakamura transformation gives a short-ranged potential and a convergent source term for the master equation of perturbations in the Kerr space-time. In this paper, we study the asymptotic behavior of the transformation, and present a new relaxed necessary and sufficient condition for the transformation to obtain the short-ranged potential in the assumption that the...

The detection of quasinormal mode with a/M = 0.95 would prove a sphere 99% soaking in the ergoregion of the Kerr space-time1

Recent numerical relativity simulations of mergers of binary black holes suggest that the maximum final value of $a/M$ is ${\sim }0.95$ for the coalescence of two equal-mass black holes with aligned spins of the same magnitude $a/M=0.994$, which is close to the upper limit $a/M=0.998$ of accretion spin-up shown by Thorne [Astrophys. J. 191, 507 (1974)]. Using the Wentzel–Kramers...

Advantage of straight walk instability in turning maneuver of multilegged locomotion: a robotics approach

, Kyoto 615-8540, JapanShinya Aoi, Takahiro Tanaka, Soichiro Fujiki, Kei Senda & Kazuo TsuchiyaDept. of Mechanical Engineering and Intelligent Systems, Graduate School of Informatics and Engineering, The ... University of Electro-Communications, 1-5-1 Choufugaoka, Choufu-shi, Tokyo 182-8585, JapanTetsuro Funato AuthorsSearch for Shinya Aoi in:Nature Research journals • PubMed • Google ScholarSearch for Takahiro

Strong restriction on inflationary vacua from the local gauge invariance III: Infrared regularity of graviton loops

It has been claimed that the super-Hubble modes of the graviton generated during inflation can make loop corrections diverge. Even if we introduce an infrared (IR) cutoff at a comoving scale as an ad hoc but practical method of regularization, we encounter secular growth, which may lead to the breakdown of perturbative expansion for a sufficiently long-lasting inflation. In this...

Effective theory of black holes in the 1/D expansion

, Spain 3 Kobayashi-Maskawa Institute, Nagoya University 4 and Takahiro Tanaka 5 Department of Physics, Osaka City University 6 Departament de F ́ısica Fonamental, Institut de Ci`encies del Cosmos 7

Strong restriction on inflationary vacua from the local gauge invariance I: Local gauge invariance and infrared regularity

The primordial perturbation is widely accepted to be generated through vacuum fluctuation of the scalar field that drives inflation. It is, however, not completely clear what the natural vacuum in the inflationary universe is, particularly in the presence of non-linear interactions. In this series of papers, we will address this issue, focusing on the condition required for the...

Strong restriction on inflationary vacua from the local gauge invariance II: Infrared regularity and absence of secular growth in the Euclidean vacuum

Takahiro Tanaka 1 Yuko Urakawa 0 Subject Index 0 Departament de Fsica Fonamental i Institut de Cincies del Cosmos, Universitat de Barcelona , Mart i Franqus 1, 08028 Barcelona, Spain 1 Yukawa

Possible existence of viable models of bi-gravity with detectable graviton oscillations by gravitational wave detectors

We discuss graviton oscillations based on the ghost-free bi-gravity theory. We point out that this theory possesses a natural cosmological background solution that is very close to the case of general relativity. Furthermore, the interesting parameter range of the graviton mass, which can be explored by observations of gravitational waves, is not at all excluded by the constraint...

Pre-DECIGO can get the smoking gun to decide the astrophysical or cosmological origin of GW150914-like binary black holes

Pre-DECIGO (DECihertz laser Interferometer Gravitational wave Observatory) consists of three spacecraft arranged in an equilateral triangle with 100 km arm lengths orbiting 2000 km above the surface of the earth. It is hoped that the launch date will be in the late 2020s. Pre-DECIGO has one clear target: binary black holes (BBHs) like GW150914 and GW151226. Pre-DECIGO can detect...

A viable explanation of the CMB dipolar statistical anisotropy

The presence of a dipolar statistical anisotropy in the spectrum of cosmic microwave background (CMB) fluctuations was reported by the Wilkinson Microwave Anisotropy Probe (WMAP), and has recently been confirmed in the Planck 2013 analysis of the temperature anisotropies. At the same time, the Planck 2013 results report a stringent bound on the amplitude of the local-type non...

Influence of light alcohol consumption on lifestyle-related diseases: a predictor of fatty liver with liver enzyme elevation in Japanese females with metabolic syndrome

Background Although heavy drinking is known to lead to liver injury, some recent studies have reported that light alcohol consumption (LAC) may play a protective role against fatty liver in the general population, and may even play a protective role against non-alcoholic fatty liver disease (NAFLD) in males with metabolic syndrome (MS). However, the association between LAC and...

A Two-Piece Derivative of a Group I Intron RNA as a Platform for Designing Self-Assembling RNA Templates to Promote Peptide Ligation

17 July 2012 Academic Editor: Janusz M. Bujnicki Copyright © 2012 Takahiro Tanaka et al. This is an open access article distributed under the Creative Commons Attribution License, which permits ... Templates to Promote Peptide Ligation Takahiro Tanaka,1 Hiroyuki Furuta,1,2 and Yoshiya Ikawa1,2,3 1Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Motooka 744

A Two-Piece Derivative of a Group I Intron RNA as a Platform for Designing Self-Assembling RNA Templates to Promote Peptide Ligation

17 July 2012 Academic Editor: Janusz M. Bujnicki Copyright © 2012 Takahiro Tanaka et al. This is an open access article distributed under the Creative Commons Attribution License, which permits