Operational measurement of relativistic equilibrium from stochastic fields alone (opens in new tab)

arXiv:2602.16765v1 Announce Type: cross Abstract: Relativistic equilibrium is described by the inverse-temperature four-vector $\beta^\mu = u^\mu/(k_B T_0)$ rather than by a frame-dependent scalar temperature. We show that $\beta^\mu$ can be reconstructed directly from electromagnetic fluctuations emitted by a drifting medium, without external probes, spectral lines, or absolute intensity calibration. A Lorentz boost converts isotropic rest-frame noise into correlated electric and magnetic f...