Thermodynamics of cosmological horizons in $f(T)$ gravity
  We explore thermodynamics of the apparent horizon in $f(T)$ gravity with both equilibrium and non-equilibrium descriptions. We find the same dual equilibrium/non-equilibrium formulation for $f(T)$ as for $f(R)$ gravity. In particular, we show that the second law of thermodynamics can be satisfied for the universe with the same temperature of the outside and inside the apparent horizon. 
Kazuharu Bamba and Chao-Qiang Geng
gr-qc astro-ph.CO hep-th