A–B 效应，全名阿哈罗诺夫－玻姆效应，是个物理学实验。它证明了矢势的重要性，是量子力学和电动力学发展史上的重要实验。

「A–B」这个名称取自设计这个实验的两位理论物理家亚基尔·阿哈罗诺夫（יקיר אהרונוב）和大卫·玻姆（יקיר אהרונוב）姓名的首字，前者因这个实验而得到1998年沃尔夫物理学奖。巧合的是，物理学家也用A表示矢势，B表示磁场，赋予A–B 效应这个名字更加深刻的涵义（见下文）。

The Aharonov–Bohm effect, sometimes called the Ehrenberg–Siday–Aharonov–Bohm effect, is a quantum mechanical phenomenon in which an electrically charged particle is affected by an electromagnetic potentials (V, A), despite being confined to a region in which both the magnetic field B and electric field E are zero. The underlying mechanism is the coupling of the electromagnetic potential with the complex phase of a charged particle's wave function, and the Aharonov–Bohm effect is accordingly illustrated by interference experiments.