3,584 research outputs found
Oscillation in power spectrum of primordial gravitational wave as a signature of higher-order stringy corrections
In low-energy effective string theory, corrections involve the
coupling of the dilaton field to Gauss-Bonnet term. We assume that the dilaton
potential is fine tuned so that the dilaton field may oscillate rapidly for a
while around the minimum of its potential but the inflation background is not
affected. By numerical method, we find that if the dilaton starts to oscillate
at the time of about e-folds before the end of inflation,
correction may bring unusual oscillations to the inflationary
gravitational wave spectrum, which might be measurably imprinted in the CMB
B-mode polarization.Comment: 19 pages, 7 figures; published version in JHEP, many details
supplemented, including 3 appendixes and 1 figure; references and comments
added, presentation improve
Chirality oscillation of primordial gravitational waves during inflation
We show that if the gravitational Chern-Simons term couples to a massive
scalar field (), the primordial gravitational waves (GWs) will show itself
the chirality oscillation, i.e., the amplitudes of the left- and right-handed
GWs modes will convert into each other and oscillate in their propagations.
This oscillation will eventually develop a permanent difference of the
amplitudes of both modes, which leads to nearly opposite oscillating shapes in
the power spectra of the left- and right-handed primordial GWs. We discuss its
implication to the CMB B-mode polarization.Comment: 14 pages, 11 figures; published version in JHEP; one figure added;
references and comments adde
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Phase-transition sound of inflation at gravitational waves detectors
It is well-known that the first-order phase transition (PT) will yield a
stochastic gravitational waves (GWs) background with a logo-like spectrum.
However, we show that when such a PT happened during the primordial inflation,
the GWs spectrum brought by the PT will be reddened, which thus records the
unique voiceprint of inflation. We assess the abilities of the GW detectors to
detect the corresponding signal.Comment: 12 pages, 6 figure
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