# Using/ Extracting data from Interpolating Functions returned from NDEigensystem I am relatively new to Mathematica and have been trying to use the NDEigensystem command to work with some quantum systems. I am able to get the accurate energy eigenvalues but am having problems with eigenfunctions; more specifically, I am having trouble actually calling values using the interpolating functions.

``m2 = 0.5; \[HBar] = 1; w = 0.5; \[ScriptCapitalO]2 = -\[HBar]^2/(2 m2) Laplacian[u[x, y], {x, y}] +    1/2 m2 w^2 (x^2 + y^2) u[x, y]; ``
``{vals, funs} =    NDEigensystem[{\[ScriptCapitalO]2,      DirichletCondition[u[x, y] == 0, True]},     u[x, y], {x, -10, 10}, {y, -10, 10}, 28,    Method -> {"PDEDiscretization" -> {"FiniteElement", {"MeshOptions" \ -> {"MaxCellMeasure" -> 0.5}}}}]; ``

As we can see above, I am using a simple 2d harmonic oscillator as my Hamiltonian, and then using the NDEigensystem command I am generating eigenvalues and eigenfunctions. I am able to get the right eigenvalues for my system as we can see below However; the eigenfunctions aren’t usable, I am trying to extract the data from the interpolating functions to no avail. From what I understand the syntax is:

``\[Psi] = funs[] \[Psi][2,3] ``

The above code should print the values of the first eigenfunction as {2,3} but it doesn’t seem to be working. I’m hoping to eventually integrate these functions to calculate expectation values, I would be very grateful for any help or advice. Posted on Categories cheapest proxies