Bloch spectrum

== English == === Noun === Bloch spectrum (quantum mechanics) A concept relating to energy spectra. Let H be the one-dimensional Schrödinger equation operator H = − d 2 d x 2 + U α , {\displaystyle H=-{\frac {d^{2}}{dx^{2}}}+U_{\alpha },} where Uα is a periodic function of period α. The Bloch spectrum of H is the set of values E for which all the solutions of (H − E)φ = 0 are bounded on the whole real axis.