2025/08/03 by Fazilah Nothlawala, Kiki Dekkers, Nothlawala, Fazilah +9 · 1 citation
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Optics (physics.optics) #Orbital Angular Momentum in Optics #Quantum Information and Cryptography #Quantum Physics (quant-ph) #Quantum and Classical Electrodynamics
paper · pdf · doi:10.48550/arxiv.2508.01716
openalex publication_date 2025/08/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Orbital angular momentum (OAM) as both classical and quantum states of light has proven essential in numerous applications, from high-capacity information transfer to enhanced precision and accuracy in metrology. Here, we extend OAM metrology to relativistic scenarios to determine the Lorentz factor of a moving reference frame, exploiting the fact that OAM is not Lorentz invariant. We show that the joint OAM spectrum from entangled states is modified by length contraction when measured by two observers moving relative to the entanglement source. This relative motion rescales the spatial dimensions, thus breaking the orthogonality of the OAM measurement process and resulting in a broadening of the joint OAM spectrum that can precisely determine the Lorentz factor. We experimentally simulate velocities up to 0.99c, confirm the predicted broadening, and use the measurement outcomes to extract the Lorentz factor. Our work provides a pathway for novel measurement techniques suitable for relativistic conditions that leverage OAM structured light as a resource.