نتایج جستجو برای: Gravitational waves

تعداد نتایج: 147803  

باسم غیور, ,

Gravitational waves are considered in thermal vacuum state. The amplitude and spectral energy density of gravitational waves are found enhanced in thermal vacuum state compared to its zero temperature counterpart. Therefore, the allowed amount of enhancement depends on the upper bound of WMAP-5 and WMAP-7 for the amplitude and spectral energy density of gravitational waves. The enhancement of ...

Journal: :iranian journal of astronomy and astrophysics 2014
iraj gholami

given the sensitivity of current ground-based gravitational wave (gw) detectors, any continuous-wave signal we can realistically expect will be at a level or below the background noise. hence, any data analysis of detector data will need to rely on statistical techniques to separate the signal from the noise. while with the current sensitivity of our detectors we do not expect to detect any tru...

2008
M. Yu. Kuchiev

Conventional non-Abelian SO(4) gauge theory is able to describe gravity provided the gauge field possesses a specific polarized vacuum state. In this vacuum the instantons and antiinstantons have a preferred direction of orientation. Their orientation plays the role of the order parameter for the polarized phase of the gauge field. The interaction of a weak and smooth gauge field with the polar...

2009
Bernard F. Schutz

Gravitational wave detection can be done by precision timing of millisecond pulsars, and (with less likelihood) by precision astrometry on distant objects whose light or radio waves pass through gravitational waves on their way to our observatories. Underlying both of these is the relatively simple theory of light propagation in spacetimes with gravitational waves, which is also the basis of in...

Journal: :Physical review letters 2009
Tomohiro Takahashi Jiro Soda

We study primordial gravitational waves produced during inflation in quantum gravity at a Lifshitz point proposed by Horava. Assuming power-counting renormalizability, foliation-preserving diffeomorphism invariance, and the condition of detailed balance, we show that primordial gravitational waves are circularly polarized due to parity violation. The chirality of primordial gravitational waves ...

Journal: :Europhysics News 2001

2017
Jiro Soda Daiske Yoshida

We explore the string axion dark matter with gravitational waves in Chern–Simons gravity. We show that the parametric resonance of gravitational waves occurs due to the axion coherent oscillation. Remarkably, the circular polarization of gravitational waves is induced by the parity violating Chern–Simons coupling. In fact, the gravitational waves should be enhanced ten times every 10−8 pc propa...

2003
Chris L. Fryer Kimberly C. B. New

Gravitational wave emission from stellar collapse has been studied for more than three decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that g...

2008
G. S. Bisnovatyi-Kogan

Gravitational lensing by gravitational wave is considered. We notice that although final and initial direction of photons coincide, displacement between final and initial trajectories occurs. This displacement is calculated analytically for the plane gravitational wave pulse. Estimations for observations are discussed.

1975
Kip S. Thorne

This article reviews current efforts and plans for gravitational-wave detection, the gravitationalwave sources that might be detected, and the information that the detectors might extract from the observed waves. Special attention is paid to (i) the LIGO/VIRGO network of earth-based, kilometer-scale laser interferometers, which is now under construction and will operate in the highfrequency ban...

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