Kramers' Theorem, also called Kramers' Degeneracy Theorem, is a result of quantum mechanics stating that every energy eigenstate of a time-reversal-symmetric system with half-integer total spin has at least one other eigenstate of the same energy related to it by time reversal. Consequently, every energy level of such a system is degenerate with even multiplicity. The theorem is named for the Dutch physicist H. A. Kramers.
Facts
StatementFor every energy eigenstate of a time reversal symmetric system with half integer total spin, there is another eigenstate with the same energy related by time reversal. 1 Classification
Statement FormCharacterization Theorem 1 Connections
Has Statement Form
Entity-backed identity for the statement-form enum value this theorem already carries, resolved to a mathematics concept by an explicit value-to-entity map (phase 3 bucket conversion, docs\design_entity_backed_browse_buckets_20260928.md). The statement-form fact itself stays on the theorem unchanged.
Sources
1. Kramers' theorem, Wikipedia
Introduction
Kramers' theorem or Kramers' degeneracy theorem states that for every energy eigenstate of a time-reversal symmetric system with half-integer total spin, there is another eigenstate with the same energy related by time-reversal.
Consequences
It was first discovered in 1930 by H. A. Kramers as a consequence of the Breit equation.
View the SourceReader Challenges (0)
No disputes yet. Spotted an error or a better source? Open the first one.
Sign in to dispute this or suggest a correction.