Beweis des Adiabatensatzes [Offprint from] Zeitschrift fur Physik 51 No. 3-4, pp. 1928

Berlin: Julius Springer, 1928. 1st Edition. FIRST EDITION, OFFPRINT ISSUE IN ORIGINAL PAPER WRAPS, OF BORN & FOCK'S 1928 PAPER PROVIDING THE FIRST PROOF OF THE ADIABATIC THEOREM IN QUANTUM MECHANICS. Of "central import in non-relativistic quantum mechanics", the theorem asserts that "a physical system remains in its instantaneous eigenstate if a given perturbation is acting on it slowly enough and if there is a gap between the eigenvalue and the rest of the Hamiltonian's spectrum" (Katanaev, Adiabatic Theorem, Steklov, 2011, 1; Kovchegov, A note on adiabatic theorem, 1).

Max Born and Vladimir Fock's work was motivated by a point of view advocated by [Paul] Ehrenfest, "which identified classical adiabatic invariants as the observables that get quantized. The theorem they proved was geared to show that quantum numbers are preserved by adiabatic deformations. Born and Fock proved an adiabatic theorem for Hamiltonian operators, H(s), with simple discrete spectrum... Their proof covers Hamiltonians like the one dimensional Harmonic oscillator, but not the Hydrogen atom, which has absolutely continuous spectrum at positive energies, and eigenvalues with multiplicities at negative energies. (ibid). CONDITION & DETAILS: Berlin: Julius Springer.Complete offprint. 8vo. (9 x 6.25 inches). Slight, small crease upper right corner. Bright and clean inside and out. Fine condition.