  The perturbative Lee-Huang-Yang (LHY) interaction proportional to $n^{3/2}$,
where $n$ is the density, creates an infinitely repulsive potential at the
center of a Bose-Einstein condensate (BEC) with net attraction, which stops the
collapse to form a self-bound state in a dipolar BEC and in a binary BEC.
However, recent microscopic calculations of the non-perturbative
beyond-mean-field (BMF) interaction indicate that the LHY interaction %with the
$n^{3/2}$ term is valid only for very small values of gas parameter $x$. We
show that a realistic non-perturbative BMF interaction can stop collapse and
form a self-bound state only in a weakly attractive binary BEC with small $x$
values ($x\lessapprox 0.01$), whereas the perturbative LHY interaction stops
collapse for all attractions. We demonstrate these aspects using an analytic
BMF interaction with appropriate weak-coupling LHY and strong coupling limits.
