Universal non-equilibrium states at the fractional quantum Hall edge

Integrability of electron dynamics in one dimension is manifested by the non-equilibrium stationary states. They emerge near a point contact coupling two quantum Hall edges with different chemical potentials. I use the non-equilibrium bosonization technique to show that the effective temperature of such states at the fractional quantum Hall edges has a universal linear dependence on the current through the contact. In contrast, the temperature at eventual equilibrium scales as the square root of the power dissipating at the point contact. I propose to use this distinction to detect these intriguing non-equilibrium states.