Resistance to Collapse: The Tensor Interaction
We consider negative-parity excitations in $^4\mbox{He}$, $J^{\pi}$=$0^-$ and $1^-$ with isospin $T$=$0$ and $T$=$1$. We show tha t, in contrast to one-particle one-hole results, in a shell model diagonalization none of the above collapses to zero energy as the strength of the tensor interaction is increased.