Photonic quantum walk in a single beam with twisted light

Abstract

Inspired by the classical phenomenon of random walk, the concept of quantum walk has emerged recently as a powerful platform for the dynamical simulation of complex quantum systems, entanglement production and universal quantum computation. Such a wide perspective motivates a renewing search for efficient, scalable and stable implementations of this quantum process. Photonic approaches have hitherto mainly focused on multi-path schemes, requiring interferometric stability and a number of optical elements that scales quadratically with the number of steps. Here we report the experimental realization of a quantum walk taking place in the orbital angular momentum space of light, both for a single photon and for two simultaneous indistinguishable photons. The whole process develops in a single light beam, with no need of interferometers, and requires optical resources scaling linearly with the number of steps. Our demonstration introduces a novel versatile photonic platform for implementing quantum simulations, based on exploiting the transverse modes of a single light beam as quantum degrees of freedom.

Main article (7 pages, 4 figures) and Supplementary Information (7 pages, 3 figures)

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Cited by in corpus (6)

• Topological Photonics
• Orbital angular momentum of photons and the entanglement of Laguerre-Gaussian modes
• Dove prism in single-path Sagnac interferometer for orbital-angular-momentum photon states
• Classical simulation of high-dimensional entanglement by non-separable angular--radial modes
• Squeezing of X waves with orbital angular momentum
• Quantum Coherence in Noisy Cellular Automata