Intermediate-coupling crossover and transition temperature

Calculate the crossover region between weakly paired electron–hole Fermi liquids and Bose-condensed interlayer excitons, including the transition temperature and the location and height of any maximum along the crossover.

Background

The paper derives controlled asymptotic results on the weak-pairing side and discusses the dilute-exciton Bose regime, but the intermediate regime has neither a small pairing parameter nor a controlled treatment of screening in the paired state.

The authors identify several quantities that remain undetermined, including the crossover profile, the maximum transition temperature, and the possible intervention of competing phases such as biexciton or crystalline states.

References

Neither the position nor the height of the maximum is determined by the calculations of this paper.

— Exciton superfluidity in two-dimensional bilayers at zero and high magnetic fields  (2610.22037 - Sarma et al., 15 Oct 2026) in Appendix A, subsection “The two crossovers between weak pairing and Bose condensation”; Section 7, “Open problems”