Primordial gravitational waves in the nano-Hertz regime and PTA data — towards solving the GW inverse problem

Jun 26, 2023
26 pages
Published in:
  • JHEP 10 (2023) 171
  • Published: Oct 27, 2023
e-Print:
Report number:
  • MITP-23-029

Citations per year

20232024202579323
Abstract: (Springer)
In recent years, several pulsar timing array collaborations have reported first hints for a stochastic gravitational wave background at nano-Hertz frequencies. Here we elaborate on the possibility that this signal comes from new physics that leads to the generation of a primordial stochastic gravitational wave background. We propose a set of simple but concrete models that can serve as benchmarks for gravitational waves sourced by cosmological phase transitions, domain wall networks, cosmic strings, axion dynamics, or large scalar fluctuations. These models are then confronted with pulsar timing data and with cosmological constraints. With only a limited number of free parameters per model, we are able to identify viable regions of parameter space and also make predictions for future astrophysical and laboratory tests that can help with model identification and discrimination.
Note:
  • 26 pages + appendix, 17 figures; v3: references added; v4: minor changes, published version
  • Cosmology of Theories BSM
  • Early Universe Particle Physics
  • Axions and ALPs
  • Phase Transitions in the Early Universe
  • new physics
  • critical phenomena
  • gravitational radiation: stochastic
  • gravitational radiation: background
  • gravitational radiation: primordial
  • gravitational radiation: frequency