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  • Open Access

Scalar-induced gravitational waves as a probe of primordial parity-violation

H. V. Ragavendra1,2,* and Nicola Bartolo1,2,3,†

  • *Contact author: ragavendra.hv@pd.infn.it
  • †Contact author: nicola.bartolo@pd.infn.it
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Phys. Rev. D 114, 063535 – Published 21 September, 2026

DOI: https://doi.org/10.1103/fptz-nm8k

Abstract

Parity violation leaves telltale trails in many cosmological observables. We illustrate parity-odd primordial scalar trispectra, that despite being of modest strength, impart detectable chirality to scalar-induced gravitational waves (SIGWs). This allows us to impose strong bounds on the parity-odd part of trispectrum. Over certain scales, we find SIGWs directly quantify parity violation in primordial non-Gaussianity, unobscured by the Gaussian contribution. Our results call for treatment of SIGWs and parity-odd trispectrum as complementary predictions of parity-violating theories.

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Phys. Rev. D 114, 063535– Published 21 September, 2026
  • Received 10 July 2025
  • Revised 16 December 2025
  • Accepted 25 August 2026
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