17 research outputs found
The uncertainty principle in resonant gravitational wave antennae and quantum non-demolition measurement schemes
A review on the current efforts to approach and to surpass the fundamental limit in the sensitivity of the Weber type gravitational wave antennae is reported. Applications of quantum non-demolition techniques to the concrete example of an antenna resonant with the transducer are discussed in detail. Analogies and differences from the framework of the squeezed states in quantum optics are discussed
Stochastic gravitational background from inflationary phase transitions
We consider true vacuum bubbles generated in a first order phase transition
occurring during the slow rolling era of a two field inflation: it is known
that gravitational waves are produced by the collision of such bubbles. We find
that the epoch of the phase transition strongly affects the characteristic peak
frequency of the gravitational waves, causing an observationally interesting
redshift in addition to the post-inflationary expansion. In particular it is
found that a phase transition occurring typically 1020 foldings
before the reheating at GeV may be detected by the next Ligo
gravity waves interferometers. Moreover, for recently proposed models capable
of generating the observed large scale voids as remnants of the primordial
bubbles (for which the characteristic wave lengths are several tens of Mpc), it
is found that the level of anisotropy of the cosmic microwave background
provides a deep insight upon the physical parameters of the effective
Lagrangian.Comment: 12 pages, 3 figures. Phys.Rev.D in pres
Quadrupole effects on the motion of extended bodies in Schwarzschild spacetime
The motion of an extended body up to the quadrupolar structure is studied in
the Schwarzschild background following Dixon's model and within certain
restrictions (constant frame components for the spin and the quadrupole tensor,
center of mass moving along a circular orbit, etc.). We find a number of
interesting situations in which deviations from the geodesic motion, due to the
internal structure of the particle, can originate measurable effects. However,
the standard clock-effect for a pair co/counter-rotating bodies spinning
up/down is not modified by the quadrupolar structure of the particle.Comment: 9 pages, latex iopart class document, no figures. Note that the
second term in the rhs of Eq. (1.2) was misprinted in the published version
of the paper [Classical and Quantum Gravity, Vol. 25, 035005 (2008)]. The
results are but correc
Light scattering by radiation fields: the optical medium analogy
The optical medium analogy of a radiation field generated by either an exact
gravitational plane wave or an exact electromagnetic wave in the framework of
general relativity is developed. The equivalent medium of the associated
background field is inhomogeneous and anisotropic in the former case, whereas
it is inhomogeneous but isotropic in the latter. The features of light
scattering are investigated by assuming the interaction region to be sandwiched
between two flat spacetime regions, where light rays propagate along straight
lines. Standard tools of ordinary wave optics are used to study the deflection
of photon paths due to the interaction with the radiation fields, allowing for
a comparison between the optical properties of the equivalent media associated
with the different background fields.Comment: 6 pages, 4 figures; published versio
The uncertainty principle in resonant gravitational wave antennae and quantum non-demolition measurement schemes
A review of current efforts to approach and to surpass the fundamental limit in the sensitivity of the Weber type gravitational wave antennae is reported. Applications of quantum non-demolition techniques to the concrete example of an antenna resonant with the transducer are discussed in detail. Analogies and differences from the framework of the squeezed states in quantum optics are discussed
Correlation between gamma ray bursts and gravitational wave bursts: the AURIGA complete data analysis
Aw idely accepted paradigm for astrophysical models of gamma ray bursts (GRB) prescribes a compact 'central engine' dominated by gravitational interactions, and therefore a concurrent emission of GRBs and gravitational wave bursts is likely to occur. Consequently, we have tested a novel and reliable method for searching for time correlation in the AURIGA and BATSE complete dataset. The analysis covers the period 1997–1999. The obtained upper limit on the averaged gravitational wave energy released in a neighbourhood of 300 s around the GRB triggers is hRMS = 1.8 × 10 −18 at 95% confidence level. We also estimate the minimum statistical coverage of confidence levels for a frequentist interpretation of our upper limit
Gravitational Radiation from Triple Star Systems
We have studied the main features of the gravitational radiation generated by
an astrophysical system constituted of three compact objects attracting one
another (only via gravitational interaction) in such a manner that stable
orbits do exist. We have limited our analysis to systems that can be treated
with perturbative methods. We show the profile of the gravitational waves
emitted by such systems. These results can be useful within the framework of
the new gravitational astronomy which will be made feasible by means of the new
generation of gravitational detectors such as LISA in a no longer far future.Comment: 10 pages plus 9 postscript figures; revtex; accepted for publication
in Int. J. Mod. Phys.