Resonance condensation in the high-T_c cuprates

he cold atomic Fermi gas has become the essential paradigm for understanding the crossover between the weak coupling Bardeen-Schrieffer-Cooper (BCS) and strong coupling Bose-Einstein Condensation (BEC) regimes of paired fermion condensates. On tuning the pairing interactions through the crossover, the superfluid condensate becomes maximally robust between the BCS and BEC regimes at what is referred to as the unitary point, giving rise to a maximally peaked phase transition anomaly in the specific heat. We find here, by tracing the jump Δγ in the electronic specific heat coefficient γ at the transition temperature T_c as a function of the gap ratio 2Δ/k_BT_c, that this same thermodynamic signature occurs in the high-T_c superconducting cuprates.  On taking Δ as the pairing gap in a cold atomic Fermi gas and as the antinodal pseudogap energy in the cuprates, we find Δγ to be asymmetrically peaked at the same value of 2Δ/k_BT_c ≅ 6.5. We show that the observation of this peak in the cuprates, and its coincidence with a normal state maximum in γ, provides a previously overlooked  thermodynamic signature of condensation at a unitary point.