Yoichi Aso

Interferometer design of the KAGRA gravitational wave detector

KAGRA is a cryogenic interferometric gravitational-wave detector being constructed at the underground nsite of Kamioka mine in Gifu prefecture, Japan. We performed an optimization of the interferomter ndesign, to achieve the best sensitivity and a stable operation, with boundary conditions of classical nnoises and under various practical constraints, such as the size of the tunnel or the mirror cooling capacity. nLength and alignment sensing schemes for the robust control of the interferometer are developed. In this npaper, we describe the detailed design of the KAGRA interferometer as well as the reasoning behind ndesign choices.

Upper limit on gravitational wave backgrounds at 0.2 Hz with a torsion-bar antenna.

We present the first upper limit on gravitational wave (GW) backgrounds at an unexplored frequency of 0.2 Hz using a torsion-bar antenna (TOBA). A TOBA was proposed to search for low-frequency GWs. We have developed a small-scaled TOBA and successfully found Ω(gw)(f)<4.3×10(17) at 0.2 Hz as demonstration of the TOBAs capabilities, where Ω(gw)(f) is the GW energy density per logarithmic frequency interval in units of the closure density. Our result is the first nonintegrated limit to bridge the gap between the LIGO band (around 100 Hz) and the Cassini band (10(-6)-10(-4)u2009u2009Hz).

Search for a Stochastic Gravitational-wave Background using a pair of Torsion-bar Antennas

We have set a new upper limit on the stochastic gravitational-wave background using two prototype torsion-bar antennas (TOBAs). A TOBA is a low-frequency gravitational-wave detector with bar-shaped test masses rotated by the tidal force of gravitational waves. As a result of simultaneous 7-hour observations with TOBAs in Tokyo and Kyoto in Japan, our upper limit with a confidence level of 95% is

5-mg suspended mirror driven by measurement-induced backaction

{mathrm{ensuremath{Omega}}}_{mathrm{gw}}{h}_{0}^{2}l1.9ifmmodetimeselsetexttimesfi{}{10}^{17}

New limit on Lorentz violation using a double-pass optical ring cavity.

at 0.035--0.830 Hz, where

Length sensing and control strategies for the LCGT interferometer

{h}_{0}

Mirror actuation design for the interferometer control of the KAGRA gravitational wave telescope

is the Hubble constant in units of

Characterization of the room temperature payload prototype for the cryogenic interferometric gravitational wave detector KAGRA

100text{ }text{ }mathrm{km}/mathrm{s}/mathrm{Mpc}

Estimation of losses in a 300 m filter cavity and quantum noise reduction in the KAGRA gravitational-wave detector

and

Ground Based Low-Frequency Gravitational-wave Detector With Multiple Outputs

{mathrm{ensuremath{Omega}}}_{mathrm{gw}}