别名:Groenewold–van Hove
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Woit · 2025-10-20
已登记出处中的最早位置:§17.2 · zh-CN。
来源短摘录与定位
§17.2 · zh-CN · machine_draft · machine-draft-not-reviewed
定理(Groenewold–van Hove)
不存在映射 ,将 上的多项式映到作用在 上的自伴算符,并满足
以及
对于 上函数所成的任意李子代数,只要次数不超过二的多项式所成子代数是其真子代数,以上条件就不可能同时成立。
证明
§17.2 · en · machine_draft · machine-draft-not-reviewed
Theorem (Groenewold-van Hove)
There is no map from polynomials on to self-adjoint operators on satisfying
and
for any Lie subalgebra of functions on in which the subalgebra of polynomials of degree at most two is a proper subalgebra.
Proof
For a detailed proof, see section 5.4 of [8], section 4.4 of [26], or chapter 16 of [37]. In outline, the proof begins by showing that Poisson brackets of degree-three polynomials produce higher-degree polynomials; moreover, for degree three and above there are no finite-dimensional subalgebras consisting of polynomials of bounded degree. The theorem’s assumptions force certain specific operator-ordering choices in degree three. These yield a contradiction in degree four, because the same degree-four polynomial has two different expressions as a Poisson bracket: