Takahiro Tanaka (Kyoto-u)

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• Takahiro Tanaka (Kyoto-u)
• ???? (?? ?)

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DETERMINATION OF THE EQUATION OF THE STATE OF THE
UNIVERSE USING 0.1 HZ GRAVITATIONAL WAVE
DETECTORS.By Ryuichi Takahashi (Tokyo, Astron.
Observ.), Takashi Nakamura (Kyoto U.),. Aug 2004.
6pp. Submitted to Phys.Rev.D e-Print Archive
astro-ph/0408547
GRAVITATIONAL WAVE MEMORY OF GAMMA-RAY BURST
JETS.By Norichika Sago (Osaka U., Dept. Earth
Space Sci.), Kunihito Ioka (Penn State U.),
Takashi Nakamura (Kyoto U.), Ryo Yamazaki (Osaka
U., Dept. Earth Space Sci.),. OU-TAP-230,
KUNS-1916, May 2004. 10pp. Published in
Phys.Rev.D70104012,2004 e-Print Archive
gr-qc/0405067
A NEW ANALYTICAL METHOD FOR SELF-FORCE
REGULARIZATION. II. TESTING THE EFFICIENCY FOR
CIRCULAR ORBITS.By Wataru Hikida (Kyoto U.,
Yukawa Inst., Kyoto), Sanjay Jhingan (Basque U.,
Bilbao), Hiroyuki Nakano (Osaka City U.),
Norichika Sago (Osaka U., Dept. Earth Space
Sci.), Misao Sasaki (Kyoto U., Yukawa Inst.,
Kyoto), Takahiro Tanaka (Kyoto U.),. Oct 2004.
21pp. e-Print Archive gr-qc/0410115
LEADING ORDER CORRECTIONS TO THE COSMOLOGICAL
EVOLUTION OF TENSOR PERTURBATIONS IN
BRANEWORLD.By Tsutomu Kobayashi, Takahiro Tanaka
(Kyoto U.),. KUNS-1933, Aug 2004. 15pp.
Published in 0410015,2004 e-Print Archive
gr-qc/0408021
THE COLLAPSE OF DIFFERENTIALLY ROTATING
SUPERMASSIVE STARS CONFORMALLY FLAT
SIMULATIONS.By Motoyuki Saijo. KUNS-1931, Jul
2004. 15pp. Temporary entry Published in
Astrophys.J.615866-879,2004 e-Print Archive
astro-ph/0407621
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The 14th Workshop on General Relativity and
Gravitation Date November 29 (Mon) - December
3 (Fri.)Place Yukawa Institute for Theoretical
Physics, Kyoto University
 
Objective
There has been an impressive progress in astrophysical/cosmological observations in recent years. Cosmology has entered an era of precision science. Astrophysical black holes have been observed in many frequency bands with better resolutions and sensitivities. Observations of gamma-ray bursts have added a new mystery to relativistic astrophysics. And, a new frontier is waiting to be explored by gravitational wave interferometers.
 
On the theoretical side, motivated by unified theories of fundamental interactions, especially string theory, many efforts have been made for studies of physics in 5-dimensional or higher dimensional spacetimes, and there is a growing interest in experimental verifications of extra dimensions. There have been also important and interesting developments in various other areas, including alternative theories of gravity, quantum gravity, and spacetime singularities, to mention a few. This year, we plan to overview these recent developments and discuss future perspectives.
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X matter (dark energy)
Ultimate Decigo
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Radiation reaction program
Energy balance ? orbital evolution
Both are the lowest order radiation reaction
force.
But, we require higher resolution for dEGW/dt.
Estimate the required accuracy using scalar
charged particle model.

• As for dEorbit/df, 4PN order((v/c)8)might be
  sufficient.
• As for dEGW/dt, convergence of PN expansion is
  too slow. We need to keep very high order.
• But we found Ylm expansion can be truncated at l
  13.

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On-going project and future

• Can we see interesting feature of GW wave form?
  A naive question(?Hikida-kuns poster)
• l2, m2 only (used for template)
  other modes
• Gravitational self-force in Schwarzshild
  spacetime (?Nakano-kuns
  poster)

or
gauge transforamtion
Force itself directly depends on gauge choice.
But, long time evolution of trajectory is
approximately gauge invariant as long as xm stays
small
same order effect on trajectory
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• Radiative radiation reaction to Carter constant,
  Q.
• A pair of E, Lz, Q specifies an orbit in Kerr
  spacetime.
• To discuss evolution of trajectory by using
  balance argument, we need dQ/dt.
• h(ret) h(adv) is regular from the beginning,
  and it gives ltdQ/dtgt correctly.
• Second order correction to the wave form.
• O(m2) in dEGW/dt.

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Namely, 2nd order perturbation
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