Universal quantum limits on single channel information, entropy and heat flow

We show that the recently discovered universal upper bound on the thermal conductance of a single channel comprising particles obeying arbitrary fractional statistics is in fact a consequence of a more general universal upper bound, involving the averaged entropy and energy currents of a single channel connecting heat reservoirs with arbitrary temperatures and chemical potentials. The latter upper bound in turn leads, via Holevo’s theorem, to a universal (i.e., statistics independent) upper bound on the optimum capacity for classical information transmission down a single, wideband quantum channel. PACS numbers: 65.50.+m, 89.70.+c, 05.30.-d, 05.30.Pr, 66.70.+f, 73.23.Ad Typeset using REVTEX