expectation value
41Multipole moment — In mathematics, especially as applied to physics, multipole moments are the coefficients of a series expansion of a potential due to continuous or discrete sources (e.g., an electric charge distribution). A multipole moment usually involves… …
42Wave function — Not to be confused with the related concept of the Wave equation Some trajectories of a harmonic oscillator (a ball attached to a spring) in classical mechanics (A B) and quantum mechanics (C H). In quantum mechanics (C H), the ball has a wave… …
43Zero-point energy — is the lowest possible energy that a quantum mechanical physical system may have; it is the energy of its ground state. All quantum mechanical systems undergo fluctuations even in their ground state and have an associated zero point energy, a… …
44Propagator — This article is about Quantum field theory. For plant propagation, see Plant propagation. Quantum field theory …
45Ehrenfest theorem — The Ehrenfest theorem, named after Paul Ehrenfest, relates the time derivative of the expectation value for a quantum mechanical operator to the commutator of that operator with the Hamiltonian of the system. It is:frac{d}{dt}langle A angle =… …
46Corner transfer matrix — In statistical mechanics, the corner transfer matrix describes the effect of adding a quadrant to a lattice. Introduced by Rodney Baxter in 1968 as an extension of the Kramers Wannier row to row transfer matrix, it provides a powerful method of… …
47Density matrix — Mixed state redirects here. For the psychiatric condition, see Mixed state (psychiatry). In quantum mechanics, a density matrix is a self adjoint (or Hermitian) positive semidefinite matrix (possibly infinite dimensional) of trace one, that… …
48Interpretation of quantum mechanics — An interpretation of quantum mechanics is a statement which attempts to explain how quantum mechanics informs our understanding of nature. Although quantum mechanics has received thorough experimental testing, many of these experiments are open… …
49Quantum state — In quantum physics, a quantum state is a mathematical object that fully describes a quantum system. One typically imagines some experimental apparatus and procedure which prepares this quantum state; the mathematical object then reflects the… …
50Universal extra dimension — In particle physics, the ADD model, also known as the model with large extra dimensions, is an alternative scenario to explain the weakness of gravity relative to the other forces. This theory requires that the fields of the Standard Model are… …
