The gap between the first two eigenvalues of a one-dimensional Schrödinger operator with symmetric potential

S. Abramovich
1991 Proceedings of the American Mathematical Society  
We prove the inequality l2lv\l ~ *-\lv\\ -^llYdl ~ ^il*ol f°r tne difference of the first two eigenvalues of one-dimensional Schrödinger operators ,2 -~í + V¡{x), ( = 0, 1 , where Vx and V0 are symmetric potentials on (a,b) and on (a, (a + b)/2), and V0 -Vx is decreasing on (a, (3a + b)/4).
doi:10.1090/s0002-9939-1991-1036981-x fatcat:uwwm2rskirhcnj3j2shauhr3fq