Christian Corda INFN-VIRGO Scalar gravitational waves from Scalar-Tensor Gravity: production and response of interferometers Miniworkshop "Supersymmetry, Supergravity, Superstrings" March 19-21 2007 Aula 131 - Dipartimento di Fisica - Largo B.Pontecorvo,3 - Pisa
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Christian Corda INFN-VIRGO Scalar gravitational waves · PDF fileChristian Corda INFN-VIRGO Scalar gravitational waves from Scalar-Tensor Gravity: production and response of interferometers
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Christian Corda INFN-VIRGO
Scalar gravitational wavesfrom Scalar-Tensor Gravity:production and response of
Aula 131 - Dipartimento di Fisica - Largo B.Pontecorvo,3 - Pisa
Introduction1) Mechanism of production of SGW from Scalar-
Tensor Gravity2) Massless case: invariance of the signal in three
different gauges3) Massless case: the frequency-dependent angular
pattern4) The small massive caseGeneralized previous results analyzed in the low-
frequencies approximation
Mechanism of production of SGWfrom Scalar-Tensor Gravity
Most general action for STG in literature
Considering the transformation
previous action reads
BD-like theory
Field equations
Klein-Gordon
Linearized theory in vacuum
Minkowski background + minimum for W
We assume
obteining
with
Effective BD
The massless case
Most simple case:
Gauge transforms (Lorenz condition)
Solutions are plan waves
Purely scalar wave: line element
TT gauge extended to scalar waves
The response of aninterferometer
Literature: low-frequencies approximation
Method of “bouncing photon” : the variationof space-time due to the scalar field iscomputed in all the travel of the photon
Computation of the variation of proper timein presence of the SGW
In the Fourier domain
The “Shibata, Nakao and Nakamura” gaugefor SGW
Purely scalar wave: line element
Reanalyzed
Same results of the TT gauge
In the Fourier domain
Used a time transform
The local Lorentz gauge for SGW:three different effects
The motion of test masses
The travel of photons in curved spacetime
The shifting of time
Gauge invariance recovered
In the Fourier domain
Angular pattern for SGW
Line element in u direction
variation of proper timein presence of the SGW inu direction
Response function in u direction
Same analysis: responsefunction in v direction
Total frequency-dependent responsefunction
Agrees with
Low frequencies
The small massive case
Treating scalars like classical waves
Frequencies have to fall in
Interval for the mass
Known for string-dilaton gravity
Parameterization of the field with the phase-velocityPresence of the mass: third component ofRiemann
Previous analysis in the local Lorentz gaugegeneralized with the aid of Fourier theorems,two effects
The motion of test masses
The travel of photons in curved spacetime
Total frequency-dependent longitudinalresponse function
ConclusionsRealistic possibility to detect SGW indifferent gauges
Realistic possibility to detect a longitudinalcomponentThe investigation of scalar components ofGW could be a tool to discriminateamong several theories of gravity
Next papersCorda C. The “Shibata, Nakao and Nakamuragauge for SGW” submitted to GRG gr-qc0610157Corda C. “The importance of the magneticcomponents of gravitational waves in theresponse function of interferometersgr-qc 0702080 accepted for IJMPD
Capozziello S.,Corda C. and de Laurentis MF“On the correct frame for theories: Jordan frameversus Einstein frame”