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A well-established feature of Fermi liquids is their linear (in T) electronic specific heat c_V at low temperatures T. However, it is less clear what happens beyond this linear regime. Recently, Toschi et al. [arXiv:0712.3723] have found evidence for kinks in c_V towards a second linear regime with different slope, which they explained by similar kinks (as a function of frequency) in the ground state self-energy.
We determine c_V in the correlated metallic phase of the half-filled Hubbard model within dynamical mean-field theory from quantum Monte Carlo calculations at all temperatures. We find a smooth decay of c_v/T in the low-T region without any signs of kinks or other singularities. The decay appears to be linked to the temperature (rather than frequency) dependence of the self-energy; the decay rate follows from an entropy sum rule. |
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