Talk:Moyal product

Moyal product implies a polarization?

So I don't really know anything about the Moyal product, but I do know this: given a polarization on a symplectic manifold, there is a privileged set of functions (classical observables) which give rise to quantum observables for which the correspondence principle holds, {f,g} = i[F,G] where on the left is denoted the Poisson bracket of functions and on the right is denoted the commutator of operators on Hilbert space, with the correspondence given by $F=-i\nabla _{X_{f}}+f$. These functions are fixed by the polarization condition [f,P]=P, where P is a polarization. Seems to me that the Moyal product for such polarizable observables should vanish after the second order term, and I guess this expectation is born out by some theorem that I only vaguely remember that polarizable observables are locally of the form of functions which are linear in the momentum (using the vertical polarization of the cotangent bundle). Seems the second order derivatives in the higher order terms will kill all the terms for such functions.

Thus the Moyal product ought to determine a set of polarizable functions, and it should be possible to recover the polarization from it. I wonder if I've got it right? My next question would be whether the Moyal product and the polarization are equivalent (that is, whether the polarization determines a Moyal product). I expect not. -lethe ^{talk +} 05:28, 20 April 2006 (UTC)

Twisted convolution

It would be very helpful to add a section on how this is related to the "twisted convolution", which is a symplectic variant of a normal convolution. See MathOverflow question, including the comment by Igor Khavkine. Jess_Riedel (talk) 18:51, 25 August 2018 (UTC)

Explicit definition seems incomplete

From the Definition section: "To provide an explicit formula, consider a constant Poisson bivector Π on R^{2n}" Π is then defined in terms of a set of unspecified real numbers (the real coefficients Π^{ij} in a series), and the C_n coefficients of the Moyal product are defined in terms of powers of Π. But there is never any formula given for the Π^{ij} coefficients.

In the end, we are left with an "explicit formula" in terms of a huge set of unknowns. How is that an explicit formula? I am not familiar with Poisson bivectors, so perhaps I am missing something. But I suspect I won't be the only one confused by this; if there is a known formula for determining the Π^{ij}'s, it should be added here. Otherwise some explanation of why they can be left undetermined would be helpful to clarify. Reductionista (talk) 02:04, 12 January 2026 (UTC)

Inside phase-space integrals

The identity given in this section can be found in Appendix B of Phys. Rev. D73, 025008 (2006). EdeYTem (talk) 06:09, 16 May 2026 (UTC)