共轭物理量(Conjugate variables)指在量子力学中其算符不对易的物理量。它的概念来自于哈密顿力学，其中共轭动量表述为拉格朗日函数对广义速度的偏微分：

在量子力学中，物理量A和B共轭的定义为，其算符不满足对易关系：

它们的一个重要特性是存在不确定关系：

最经典的共轭物理量包括位置/动量、时间/能量等。

Conjugate variables are pairs of variables mathematically defined in such a way that they become Fourier transform duals of one another, or more generally are related through Pontryagin duality. The duality relations lead naturally to an uncertainty in physics called the Heisenberg uncertainty principle relation between them. In mathematical terms, conjugate variables are part of a symplectic basis, and the uncertainty principle corresponds to the symplectic form.