3 papers
math.SP2020
Spectral gaps of 1-D Robin Schrödinger operators with single-well potentials
Mark S. Ashbaugh, Derek Kielty
We prove sharp lower bounds on the spectral gap of 1-dimensional Schrödinger operators with Robin boundary conditions for each value of the Robin parameter. In particular, our lowe…
math.SP2020
A moment inequality and positivity for signed graph Laplacians
Ikemefuna Agbanusi, Jared C. Bronski, Derek Kielty
A number of recent papers have considered signed graph Laplacians, a generalization of the classical graph Laplacian, where the edge weights are allowed to take either sign. In the…
math.SP2018
Singular limits of sign-changing weighted eigenproblems
Derek Kielty
Consider the eigenvalue problem generated by a fixed differential operator with a sign-changing weight on the eigenvalue term. We prove that as the negative part of the weight is r…