Category
page 1Theorems in quantum mechanics
Bell's theorem
in quantum physics, the theorem that locally causal hidden-variable theories cannot reproduce correlations predicted by quantum mechanics
charge-parity-time symmetry
physics theorem
Ehrenfest theorem
theorem that the time evolution of the expectation value of a quantum observable is proportional to that of the commutator between the observable and the Hamiltonian (plus that of any explicit time dependence of the operator, if any)
spin-statistics theorem
theorem that, in a Lorenz-invariant local quantum field theory, particles with integer spins are bosons, while particles with half-integer spins are fermions
no-cloning theorem
in quantum information theory, the statement that it is impossible to create an independent and identical copy of an arbitrary unknown quantum state
Bloch theorem
Fundamental theorem in condensed matter physics
Hellmann–Feynman theorem
theorem that relates the derivative of the total energy with respect to a parameter, to the expectation value of the derivative of the Hamiltonian with respect to that same parameter
Mermin–Wagner theorem
theorem about the impossibility of spontaneous symmetry breaking in two-dimensional systems at finite temperature
adiabatic theorem
theorem
Wigner's theorem
theorem in the mathematical formulation of quantum mechanics
Wigner–Eckart theorem
theorem
Kramers theorem
theorem in quantum mechanics that energy levels with half-integer spin are degenerate
Landau–Yang theorem
selection rule that a massive particle with spin 1 cannot decay into two photons
Coleman–Mandula theorem
theorem that spacetime symmetries cannot mix with internal ones in a relativistic quantum field theory
no-communication theorem
no-go theorem in quantum information theory, forbidding some communication during measurement of entangled states
Kochen–Specker theorem
theorem that any hidden-variable theory describing quantum mechanics must be contextual
Furry's theorem
theorem in quantum physics that, in a theory preserving charge conjugation symmetry, a Feynman diagram consisting of a closed fermion loop connected to an odd number of vertices integrates to zero
quantum no-deleting theorem
in quantum information theory, the no-go theorem that, given two copies of a quantum state, one cannot delete only one of the copies
Haag–Lopuszanski–Sohnius theorem
supersymmetric generalization of Coleman–Mandula theorem: the only possible (super-)symmetries of a nontrivial 4d Lorentzian QFT are (super-)Poincaré symmetry and internal symmetries
Weinberg–Witten theorem
constraints on possible particle properties