Gauge-Invariant Tensor Perturbations Induced from Baryon-CDM Relative Velocity and the B-mode Polarization of the CMB
arXiv:2104.03330 · doi:10.1103/PhysRevD.104.083534
Abstract
At second-order, scalar perturbations can source traceless and transverse perturbations to the metric, called induced gravitational waves (IGW). The apparent gauge-dependence of the IGW obscures the interpretation of the stochastic gravitational-wave signal. To elucidate the gauge dependence, we study the IGW from manifestly gauge-invariant scalar perturbations, namely, the relative velocity between the baryon and cold dark matter. From this relative velocity perturbation, we compute the dimensionless gravitational wave power spectrum and the corresponding expected angular power spectrum of the B-mode polarization of the cosmic microwave background. Although the effect turns out to be unobservably small, the calculation demonstrates both the importance of using observable quantities to remove the gauge ambiguity and the observable consequences of tensor perturbations which are not propagating gravitational waves.
arXiv comment12 pages, 3 figures; Published version: appendix expanded and typos corrected
References in corpus (31)
- Planck 2015 results. XIII. Cosmological parameters
- Efficient Computation of CMB anisotropies in closed FRW models
- The Simons Observatory: Science goals and forecasts
- Cuba - a library for multidimensional numerical integration
- The NANOGrav 12.5-year Data Set: Search For An Isotropic Stochastic Gravitational-Wave Background
- Gravitational Wave Spectrum Induced by Primordial Scalar Perturbations
- The linear power spectrum of observed source number counts
- Relative velocity of dark matter and baryonic fluids and the formation of the first structures
- New Perspective on Galaxy Clustering as a Cosmological Probe: General Relativistic Effects
- Upper Limits on the Stochastic Gravitational-Wave Background from Advanced LIGO's First Observing Run
- Stochastic Gravitational Wave Backgrounds
- CMB polarization from secondary vector and tensor modes
- Large-scale clustering of galaxies in general relativity
- Second-order Perturbations of the Friedmann World Model
- Pulsar Timing Array Constraints on Primordial Black Holes with NANOGrav 11-Year Data Set
- Cosmic Microwave Background Fluctuations from Gravitational Waves: An Analytic Approach
- Second-order Gauge Invariant Cosmological Perturbation Theory: -- Einstein equations in terms of gauge invariant variables --
- Cosmological Magnetic Field: a fossil of density perturbations in the early universe
- Induced gravitational wave background and primordial black holes
- LiteBIRD: JAXA's new strategic L-class mission for all-sky surveys of cosmic microwave background polarization
- Gauge Independence of Induced Gravitational Waves
- Scalar Induced Gravitational Waves in Different Gauges
- Gravitational wave constraints on the primordial black hole dominated early universe
- The NANOGrav 12.5-year Data Set: Wideband Timing of 47 Millisecond Pulsars
- On the Gauge Invariance of Cosmological Gravitational Waves
- Gauge dependence of gravitational waves generated from scalar perturbations
- The radiative transfer at second order: a full treatment of the Boltzmann equation with polarization
- On the gauge dependence of gravitational waves generated at second order from scalar perturbations
- Approximate gauge independence of the induced gravitational wave spectrum
- Total Angular Momentum Waves for Scalar, Vector, and Tensor Fields
- Gauge transformation of scalar induced gravitational waves