2006/08/31 by B. L. Voronov, D. M. Gitman, Д. М. Гитман +1
Mathematics · Physics and Astronomy · #Atomic and Molecular Physics #Charge (physics) #Cold Atom Physics and Bose-Einstein Condensates #Coulomb #Crystallography and Radiation Phenomena #Eigenfunction #Eigenvalues and eigenvectors #Electric charge #Electron #Hamiltonian (control theory) #Mathematical physics #Mathematics #Physics #Point particle #Quantum #Quantum dynamics #Quantum mechanics #Relativistic quantum mechanics #hep-th #math-ph #math.MP #quant-ph
paper · pdf · doi:10.1007/s11232-007-0004-5
published as Theor.Math.Phys.150:34-72,2007 · 44 pages, LaTex file, to be published in Teor.Mat.Fiz. (Theor.Math.Phys.)
arxiv created 2006/11/21 · openalex publication_date 2007/01/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We consider the quantum-mechanical problem of a relativistic Dirac particle moving in the Coulomb field of a point charge Ze. In the literature, it is often declared that a quantum-mechanical description of such a system does not exist for charge values exceeding the so-called critical charge with % Z=α-1=137 based on the fact that the standard expression for the lower bound state energy yields complex values at overcritical charges. We show that from the mathematical standpoint, there is no problem in defining a self-adjoint Hamiltonian for any value of charge. What is more, the transition through the critical charge does not lead to any qualitative changes in the mathematical description of the system. A specific feature of overcritical charges is a non uniqueness of the self-adjoint Hamiltonian, but this non uniqueness is also characteristic for charge values less than the critical one (and larger than the subcritical charge with Z=(√(3)% /2)α-1=118). We present the spectra and (generalized) eigenfunctions for all self-adjoint Hamiltonians. The methods used are the methods of the theory of self-adjoint extensions of symmetric operators and the Krein method of guiding functionals. The relation of the constructed one-particle quantum mechanics to the real physics of electrons in superstrong Coulomb fields where multiparticle effects may be of crucial importance is an open question.