Gravitational Wave Signatures from Warm Dark Energy
  Motivated by some of the recent swampland conjectures, we study a model of
dark energy, in which a quintessence axion slowly rolls in a steep potential
due to its interactions with a U(1) or an SU(2) gauge field. The gauge fields
produced by this interaction can generate a stochastic gravitational wave
background with frequencies in the range $f \sim \left(10^{-16} -
10^{-14}\right)\; {\rm Hz}$. Gravitational waves in this range can in principle
be probed by CMB spectral distortions. We show that the amplitude of the signal
produced in this model is above the level for detectability only under very
favourable choices of parameters.
