  In this talk, based on arXiv:2301.11345, arXiv:2305.16388, arXiv:2311.12694,
we discuss the production of primordial gravitational waves (GW) sourced by
graviton bremsstrahlung during inflationary reheating. For reheating, we
consider inflaton decays and annihilations into pairs of bosons or fermions,
assuming an inflaton $\phi$ that oscillates around a generic monomial potential
$V(\phi) \propto \phi^n$. The GW spectrum exhibits distinct features depending
on the underlying reheating dynamics, which is controlled by the inflaton
potential and the type of coupling between the inflaton and the matter fields.
We show that the produced stochastic GW background could be probed in
next-generation GW detectors, especially at high frequencies. We further
highlight the potential of bremsstrahlung-induced GW to probe the underlying
dynamics of reheating.
