2020/04/30 by Xiang Xi, Jingwen Ma, Zhong-Hao Zhou +8 · 9 citations
Mathematics · Physics and Astronomy · #Angular momentum #Central force #Classical mechanics #Experimental and Theoretical Physics Studies #Four-force #Helmholtz free energy #Lorentz force #Lorentz transformation #Mathematics #Mechanical and Optical Resonators #Optical force #Optical tweezers #Physics #Quantum and Classical Electrodynamics #Quantum mechanics #Symmetry (geometry) #Test theories of special relativity #Theoretical physics #Theory of relativity #physics.app-ph #physics.class-ph #physics.optics
paper · pdf · open access · doi:10.1364/optica.423877
published in Optica 8(11), 1435 (Optica Publishing Group)
arxiv created 2021/05/24 · openalex publication_date 2021/06/14 · openalex created_date 2021/06/22 · arxiv updated 2021/11/05 · openalex updated_date 2026/07/28
The textbook-accepted formulation of electromagnetic force was proposed by Lorentz in the 19th century, but its validity has been challenged due to incompatibility with the special relativity and momentum conservation. The Einstein–Laub formulation, which can reconcile those conflicts, was suggested as an alternative to the Lorentz formulation. However, intense debates on the exact force are still going on due to lack of experimental evidence. Here, we report the first experimental investigation of angular symmetry of optical force inside a solid dielectric, aiming to distinguish the two formulations. The experiments surprisingly show that the optical force exerted by a Gaussian beam has components with the angular mode numbers of both 2 and 0, which cannot be explained solely by the Lorentz or the Einstein–Laub formulation. Instead, we found that a modified Helmholtz theory by combining the Lorentz force with additional electrostrictive force can explain our experimental results. Our results represent a fundamental leap forward in determining the correct force formulation and will update the working principles of many applications involving electromagnetic forces.