arXiv subjects

Moslem Mahdavifar

Publications and source records attributed to Moslem Mahdavifar.

4 recordsLinked to original sources

arXiv2025

Entanglement dynamics of light's orbital angular momentum under a Lorentz boost

In this study, we report on the evolution of photonic orbital angular momentum (OAM) entanglement in inertial reference frames under a Lorentz boost, covering the general cases of zero and non-zero relative motion between observers of the entangled state. We find that entanglement undergoes significant changes that are observer dependent, asymptotically approaching a minimum at very large velocities close to the light cone from the viewpoint of the stationary observers in the rest frame, and degrading completely from the viewpoint of the moving observer. Our results, as demonstrated through entanglement metrics such as entanglement entropy and purity, show that OAM and OAM entanglement are observer dependent, raising pertinent questions on the invariance of such entangled states to spacetime transformations.

quant-ph↗

arXiv2025

Orbital angular momentum of entangled photons as a probe for relativistic effects

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.

quant-ph↗

arXiv2023

Quantum Nature of Quasi-Classical States and Highest Possible Single-Photon Rate

Observation of the purely quantum mechanical effects of quasi-classical states is of utmost importance since these states are realistic sources of radiation and do not have any shortage in photon numbers. Therefore, they do not face the scalability problem as much as other single-photon sources do, which makes them much more robust against photon loss. Moreover, these states define the standard quantum limit. Hence, finding their quantum signature hints to the highest possible single-photon rate. In this manuscript, we attempt to demonstrate this idea theoretically using known dynamics and then present supporting experimental results. Through our experiment, we realize two-photon bunching from the transfer of quantum information using such states with the projection of orbital angular momentum from a continuous wave source. Our work is a step forward towards a more diverse and practical use of quasi-classical states in the domain of quantum optics and quantum information.

quant-ph↗

arXiv2023

Violating Bell inequality using weak coherent states

We present an experimental investigation of two-photon interference using a continuous-wave laser. We demonstrate the violation of the CHSH inequality using the phase randomized weak coherent states from a continuous wave laser. Our implementation serves as an approach to reveal the quantum nature of a source that is considered to be a classical source.

quant-ph↗