Observation of quantum limit of anyonic Heat Flow

Quantum mechanics sets a bound on information flow, and thus also a bound on heat flow. Indeed, the heat conductance of a ballistic one-dimensional channel was predicted to be a universal quantity (depending only on universal constants), called the `quantum limit of heat conductance'; namely, ($\pi^{\mathrm{2}}$k$_{\mathrm{B}}^{\mathrm{2}}$T)/3h [1]. Note that this constant does not depend on the charge, the statistics, or the interaction strength of the heat-carrying particles. This had been verified experimentally for weakly interacting phonons [2], photons [3] and electronic Fermi-liquids [4]. Here, we report the first observation of quantized heat flow in a strongly interacting system of 2D electrons in the fractional quantum Hall regime. We observed such quantization in the particle-like 1/3 state and in several hole-like states with fillings between 1/2 and 1. Since the heat in these fractional states is carried by fractionally charged and neutral quasiparticles, the observed quantization is relevant for both, independent on their anyonic statistics [5]. [1] J. B. Pendry, J. Phys. A 16, 2161 (1983) [2] K. Schwab et al., Nature 404, 974 (2000). [3] M. Meschke et al., Nature 444, 187 (2006). [4] S. Jezouin et al., Science 342, 601(2013). [5] C. L. Kane et al., Phys. Rev. B 55, 15852 (1997).