Photonic orbital angular momentum in turbulence: vortex splitting and adaptive optics

Mon, 21 Sep 2020 00:00:00 +0000

Recent works revealed that transmission of light beams carrying orbital-angular-momentum (OAM) through turbulence causes the optical vortex defining these beams to split into multiple vortices with unit topological charge. Here, we consider the numerical propagation of orbital-angular-momentum (OAM) modes through a horizontal atmospheric channel. By analysing the beam’s phase front after transmission through turbulence, we confirm the occurence of vortex splitting, but we also witness the emergence of vortex-antivortex pairs. Moreover, by performing performing a decomposition of the transmitted wave into OAM modes, we show that while adaptive optics cannot cancel vortex splitting, it still is pretty efficient in diminishing the turbulence-induced crosstalk between different OAM modes.

Entanglement of truncated quantum states

Wed, 01 Jan 2020 00:00:00 +0000

We investigate the impact of Hilbert-space truncation upon the entanglement of an initially maximally entangled m × m bipartite quantum state, after propagation under an entanglement-preserving n × n (n ≥ m) unitary. Truncation-physically enforced, e.g., by a detector’s finite cross section-projects the state onto an s × s-dimensional subspace (3 ≤ s ≤ n). For a random local unitary evolution, we obtain a simple analytical formula that expresses the truncation-induced entanglement loss as a function of n, m and s.

Andreas Buchleitner | LIP6 - Équipe QI

Photonic orbital angular momentum in turbulence: vortex splitting and adaptive optics

Entanglement of truncated quantum states