Müller, David
(2016):
Minimax Principles, HardyDirac Inequalities, and Operator Cores for Two and Three Dimensional CoulombDirac Operators.
In: Documenta Mathematica, Vol. 21: pp. 11511170

Full text not available from 'Open Access LMU'.
Abstract
For n is an element of{2, 3} we prove minimax characterisations of eigenvalues in the gap of the n dimensional Dirac operator with an potential, which may have a Coulomb singularity with a coupling constant up to the critical value 1/(4  n). This result implies a socalled HardyDirac inequality, which can be used to define a distinguished selfadjoint extension of the CoulombDirac operator defined on C0(infinity)(Rn \ {0};C2(n1)) as long as the coupling constant does not exceed 1/(4  n). We also find an explicit description of an operator core of this operator.