Energy current and its statistics in the nonequilibrium spin-boson model: Majorana fermion representation

摘要: We study the statistics of thermal energy transfer in nonequilibrium (two-bath) spin-boson model. This quantum many-body impurity system serves as a canonical model for transport. Our method makes use Majorana fermion representation spin operators, combination with Keldysh Green's function approach. derive an analytical expression cumulant generating steady state limit, and show that it satisfies Gallavotti-Cohen fluctuation symmetry. obtain expressions heat current its noise, valid beyond sequential co-tunnelling regimes. results satisfy mechanical bound interacting nanojunctions. Results are compared other approximate theories, well non-interacting model, fully harmonic junction.