The fractional quantum Hall effect (FQHE) at filling 5/2, which is usually understood as a p-wave paired state of underlying quasiparticles - composite fermions, transforms into a nematic phase under pressure \cite{csathy0, csathy}. A pair density wave (PDW) may be a precursor, underlying state for this behaviour, and such state(s) were proposed that maintain the weak-pairing feature of the uniform paired state \cite{frad}. Based on considerations in the weak-coupling regime of a microscopic description of the pairing phase (to mimic the phase as it gives way to a nematic phase in the experiments), we argue that the ensuing and relevant PDW state has a strong-pairing character. Furthermore, due to the existence of a single collective mode associated with the order parameter in the uniform paired phase, in the weak-coupling regime, the p-wave paired state, in general (for example, in the superconducting state of electrons), may be prone to a PDW instability.
@article{arxiv.2511.19567,
title = {Pair density wave in the fractional quantum Hall effect at even denominator},
author = {M. V. Milovanović},
journal= {arXiv preprint arXiv:2511.19567},
year = {2025}
}