• Yang-Mills thermodynamics;
  • low-temperature black-body anomaly;
  • spectral gap;
  • bolometry and radiometry.


In contrast to earlier reports, where the spectrum of the energy density of photonic black-body radiation modified by SU(2) effects was discussed, we discuss the low-frequency spectrum of the radiance at temperatures ranging between 5 and 20 Kelvin. We conclude that compared to the conventional theory the only observable effect is associated with the spectral gap (total screening) which for T≥ 4.3 K scales with temperature T as ν*(T)}/GHz = 42.70 (T/K)-0.53 + 0.21. We also discuss how a low-temperature black body cavity under the influence of a sufficiently strong static electric field is forced to emit according to Planck's radiation law (pure U(1) theory) even at low frequencies and how this effect can be utilized to measure SU(2) induced deviations.