A Lieb-Thirring inequality bounds a sum of powers of the negative eigenvalues of a Schrödinger operator by an integral of its potential (Lieb and Thirring 1976). In
one dimension, write on
with
. For
, the inequality
has the form
where the negative eigenvalues are counted with multiplicity. The optimal constant is the least that works for every admissible potential. The semiclassical
value is
where
is the gamma function.