Suppression of electronic specific heat in the low-temperature normal state of cuprates: a possible scenario from coupling to superconducting fluctuations

Recent measurements on the model cuprate YBCO revealed that the electronic specific heat in the high-field normal state is significantly smaller than the value anticipated from the full band Fermi surface, despite the fact that the state displays properties expected from a conventional Fermi liquid. To explore theoretically the possible mechanism of this entropy depletion, we study how the superconducting fluctuations (a residual of the superconducting order in zero field) may play a key role in the process. We propose a low-energy effective field theory consisting of electrons coupled to bosonic superconducting fluctuations, and investigate the temperature dependence of the specific heat by using a controlled large-N approach. We also discuss some alternative explanations to the puzzle of missing specific heat in the low-temperature normal state of YBCO.