On the number of nodal domains of the 2D isotropic quantum harmonic   oscillator -- an extension of results of A. Stern --
  In the case of the sphere and the square, Antonie Stern (1925) claimed in her PhD thesis the existence of an infinite sequence of eigenvalues whose corresponding eigenspaces contain an eigenfunction with two nodal domains. These two statements were given complete proofs respectively by Hans Lewy in 1977, and the authors in 2014 (see also Gauthier-Shalom--Przybytkowski (2006)). The aim of this paper is to obtain a similar result in the case of the isotropic quantum harmonic oscillator in the two dimensional case. 
Pierre B\'erard (IF), Bernard Helffer (LM-Orsay, LMJL)
math.SP math-ph math.AP math.MP