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In a more general sense, the Poisson bracket is used to define a Poisson algebra, of which the algebra of functions on a Poisson manifold is a special case. There are other general examples, as well: it occurs in the theory of Lie algebras , where the tensor algebra of a Lie algebra forms a Poisson algebra; a detailed construction of how this ...
Given that in general for a closed system with generalized coordinates q i and canonical momenta p i, [3] = =, = =, it is immediate (recalling x 0 = ct, x 1 = x, x 2 = y, x 3 = z and x 0 = −x 0, x 1 = x 1, x 2 = x 2, x 3 = x 3 in the present metric convention) that = = (,) is a covariant four-vector with the three-vector part being the ...
The three components L i of the angular momentum vector L have the Poisson brackets [1] {,} = =, where i =1,2,3 and ε ijs is the fully antisymmetric tensor, i.e., the Levi-Civita symbol; the summation index s is used here to avoid confusion with the force parameter k defined above.
Another useful result is Poisson's theorem, which states that if two quantities and are constants of motion, so is their Poisson bracket {,}. A system with n degrees of freedom, and n constants of motion, such that the Poisson bracket of any pair of constants of motion vanishes, is known as a completely integrable system .
The (2n + 1) constrained phase-space variables (x i, p i) obey much simpler Dirac brackets than the 2n unconstrained variables, had one eliminated one of the x s and one of the p s through the two constraints ab initio, which would obey plain Poisson brackets. The Dirac brackets add simplicity and elegance, at the cost of excessive (constrained ...
According to the correspondence principle, in certain limits the quantum equations of states must approach Hamilton's equations of motion.The latter state the following relation between the generalized coordinate q (e.g. position) and the generalized momentum p: {˙ = = {,}; ˙ = = {,}.
Momentum space is the set of all momentum vectors p a physical system can have; the momentum vector of a particle corresponds to its motion, with dimension of mass ⋅ length ⋅ time −1. Mathematically, the duality between position and momentum is an example of Pontryagin duality .
As it turns out, the only pairs of these properties that lead to self-consistent, nontrivial solutions are 2 & 3, and possibly 1 & 3 or 1 & 4. Accepting properties 1 & 2, along with a weaker condition that 3 be true only asymptotically in the limit ħ →0 (see Moyal bracket ), leads to deformation quantization , and some extraneous information ...