REVIEW 6 cited by
On the gauge dependence of gravitational waves generated at second order from scalar perturbations
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
abstract
We revisit and clarify the gauge dependence of gravitational waves generated at second order from scalar perturbations. In a universe dominated by a perfect fluid with a constant equation-of-state parameter $w$, we compute the energy density of such induced gravitational waves in the Newtonian, comoving, and uniform curvature gauges. Huge differences are found between the Newtonian and comoving gauge results for any $w \,(\ge 0)$. This is always caused by the perturbation of the shift vector. Interestingly, the Newtonian and uniform curvature gauge calculations give the same energy density for $w>0$. In the case of $w=0$, the uniform curvature gauge result differs only by a factor from that of the comoving gauge, but deviates significantly from that of the Newtonian gauge. Our calculation is done analytically for $w=0$ and $w=1/3$, and our result is consistent with the previous numerical one.
Forward citations
Cited by 6 Pith papers
-
Observable Gravitational Wave Strain at Second Order
At second order, the gravitational-wave strain measured by geodesic observers exchanging light pulses is the transverse-traceless metric perturbation in the Newton gauge (h_N^(2)).
-
General SIGW source for reheating dynamics
A gauge-invariant source term for scalar-induced gravitational waves is derived for smooth reheating with an inflaton field transitioning into fluids.
-
Scalar-induced gravitational waves from a box-shaped curvature power spectrum
Analytic SIGW spectra for a log-box curvature power spectrum: narrow-box geometric overlap factor turning IR slope k^{3}ln^{2}k into k^{2}ln^{2}k, plus broad-box product of universal edge functions.
-
Implications for Pulsar Timing Arrays of Sub-solar Black Hole Detections: From LVK to Einstein Telescope and Cosmic Explorer
A Bayesian analysis shows that a future sub-solar PBH detection would make the primordial SIGW interpretation of PTA data favored over the SMBH interpretation, but this preference is driven by the detection prior.
-
On the Gauge Invariance of Secondary Gravitational Waves
The paper argues that discarding non-light-speed modes of the second-order tensor perturbation makes the induced gravitational wave energy density gauge-invariant in both adiabatic and isocurvature scenarios.
-
Tensor induced gravitational waves
Second-order tensor-induced gravitational waves can shift the inferred parameters of small-scale primordial gravitational wave models fitted to NANOGrav 15-year data, with one model favored by Bayes factors.
Discussion (0). Continue with ORCID to comment.