Quantum computer networks with the orbital angular momentum of light

Abstract

Inside computer networks, different information processing tasks are necessary to deliver the user data efficiently. This processing can also be done in the quantum domain. We present simple optical quantum networks where the orbital angular momentum of a single photon is used as an ancillary degree of freedom which controls decisions at the network level. Linear optical elements are enough to provide important network primitives like multiplexing and routing. First we show how to build a simple multiplexer and demultiplexer which combine photonic qubits and separate them again at the receiver. We also give two different self-routing networks where the OAM of an input photon is enough to make it find its desired destination.Comment: 7 pages, 3 figures, comments welcom

Deterministic CNOT gate and entanglement swapping for photonic qubits using a quantum-dot spin in a double-sided optical microcavity

“…As reported in Refs. [64,67] network primitives such as multiplexing and routing [68,69]. These imply the feasibility of our scheme using QDs in the microcavity system.…”

High efficiency frequency upconversion of photons carrying orbital angular momentum for a quantum information interface

“…In recent years, following the pioneering work of entanglement in OAM states of light at single-photon level [6], great progress has been made in OAM encoded quantum cryptography [7] and high-dimensional entanglement [8,9]. Besides these ground-breaking experiments on the fundamental research, using the OAM of light as photonic qubits shows great potential in applications of optical communication [10][11][12], optimal quantum cloning [13], quantum computer networks [14], quantum key distribution [15], and quantum memory [16,17]. However, OAM qubits at optical fiber [18] telecommunication wavelengths around 1550 nm could not match the quantum information storage and processing devices based on atoms, ions or NV color centers that absorb and emit photons at visible wavelengths around 600~700 nm.…”

Transfer of orbital angular momentum superposition from asymmetric Laguerre–Gaussian beam to Bose–Einstein Condensate

“…After the pioneering work of Allen et al [13] on optical vortex carrying orbital angular momentum (OAM), associated with its spatial mode structure, there have been remarkable advancement in creation [14][15][16], manipulation [17] and detection [18][19][20] of the OAM states of light along with its utilization to generate the vortex states in BEC [21]. In this regard, the utilization of optical vortex carrying OAM is already established as an attractive opportunity in high-density data transmission [22], manipulating the motion of microparticles in optical tweezers [23], optical trapping of atoms [24][25][26][27][28] and quantum information processing [18,[29][30][31][32]. However, the interaction of an atom with optical vortex, in the dipole approximation, inevitably transfers OAM to the center-of-mass (c.m.)…”