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Banach spaces, function spaces, real functions, integral transforms, theory of distributions, measure theory.

15 votes
2 answers
1k views

Is zero a hydrogen eigenvalue?

This question has been bugging me for some time. Take the hamiltonian for the hydrogen atom: $$\hat{H}=-\frac{1}{2}\nabla^2-\frac{1}{r},$$ acting on (a domain contained in) $L^2(\mathbb{R}^3)$. It is …
Emilio Pisanty's user avatar
6 votes

Is zero a hydrogen eigenvalue?

I looked in Anatoly's references, and Quantum mechanics for mathematicians by Leon A. Takhtajan does have the calculation of the continuum wavefunctions, though it does not do the $k=0$ case. The eige …
Emilio Pisanty's user avatar
3 votes
1 answer
223 views

Analytic continuation of instantaneous eigenstates of a time-dependent hamiltonian

We are considering the instantaneous eigenstates of an analytically time-dependent hamiltonian and I would like to know how legitimate it is to extend them to the complex plane. Specifically, our ham …
Emilio Pisanty's user avatar
2 votes
0 answers
146 views

Subspace where an operator is positive

Given a self-adjoint operator $\hat{T}$ on a Hilbert space $\mathcal{H}$, and assuming it has a basis of eigenvectors $\{\phi_n\}$ such that $\hat{T}\phi_n=\lambda_n\phi_n$, one can consider the subsp …
Emilio Pisanty's user avatar