We consider the stability problem for a unitary N+1 fermionic model, i.e., a system of $N$ identical fermions interacting via zero-range interactions with a different particle, in the case of infinite two-body scattering length. We present a slightly more direct and simplified proof of a recent result obtained in \cite{ CDFMT}, where a sufficient stability condition is proved under a suitable assumption on the mass ratio.
Categories: cond-mat.quant-gas math-ph math.MP