Universal entanglement decay in atmospheric turbulence

TL;DR

This paper demonstrates that entanglement of orbital angular momentum photons universally decays exponentially when propagating through atmospheric turbulence, using the phase correlation length as a key parameter.

Contribution

It introduces the phase correlation length of an OAM beam and shows its role in universal exponential entanglement decay in turbulence.

Findings

Entanglement decays exponentially with turbulence strength.

The phase correlation length governs the decay rate.

Universal behavior independent of specific OAM states.

Abstract

We consider the propagation of two photonic qubits, initially maximally entangled in their orbital angular momenta (OAM), across a turbulent atmosphere. By introducing the {\it phase correlation length} of an OAM beam, we show that the entanglement of OAM photons exhibits a universal exponential decay under turbulence.