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Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)

Quantum state fusion in photons

Nicolò Spagnolo, Chiara Vitelli, Lorenzo Aparo, Fabio Sciarrino, Enrico Santamato, Lorenzo Marrucci

Published May 1, 2013• 1 citation
Publisher

Abstract

Quantum information technology is based on our ability to manipulate and transmit the internal quantum states of physical systems, such as photons, ions, atoms, superconducting circuits, etc [1,2]. In photonic systems, a strong research effort has been recently devoted to expanding the useful quantum space by two alternative approaches, which have proceeded in parallel. One of them relies on increasing the number of involved photons, while the other one relies on exploiting different degrees of freedom of the same photon, such as polarization, time-bin, wavelength, propagation paths, and orbital angular momentum. We introduce and prove experimentally a novel quantum-state manipulation processes, namely fusion, that can be used to bridge these two approaches, allowing for their full integration.

DOI
10.1109/cleoe-iqec.2013.6801725

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Quantum information technology is based on our ability to manipulate and transmit the internal quantum states of physical systems, such as photons, ions, atoms, superconducting circuits, etc [1,2]. In photonic systems, a strong research effort has been recently devoted to expanding the useful quantum space by two alternative approaches, which have proceeded in parallel. One of them relies on increasing the number of involved photons, while the other one relies on exploiting different degrees of freedom of the same photon, such as polarization, time-bin, wavelength, propagation paths, and orbital angular momentum. We introduce and prove experimentally a novel quantum-state manipulation processes, namely fusion, that can be used to bridge these two approaches, allowing for their full integration.
The field of high-dimensional quantum photonics involves the use of multimode photonic degrees-of-freedom such as the spatial, temporal, or spectral structure of light to encode multi-level quantum states. Recent years have seen rapid progress in the development of methods to generate, manipulate, and distribute such quantum states of light and their use in a range of quantum technology applications that offer practical advantages over conventional qubit-based approaches. High-dimensional quantum states of light encoded in photonic time-bins, frequency-bins, transverse-spatial modes, waveguide paths, and temporal modes have enabled noise-robust fundamental tests of quantum mechanics, error-resilient and high-capacity quantum communication protocols, andas well as efficient approaches for quantum information processing, to name just a few examples. However, research in this field has progressed fairly independently, with little exchange across different photonic degrees-of-freedom or between experiment and theory and no comprehensive comparison between degrees-of-freedom. This roadmap aims to bridge this gap by surveying progress in each area and identifying shared challenges and opportunities that cut across two or more photonic degrees-of-freedoms. We review early work and state-of-the-art experimental techniques under development for high-dimensional quantum states encoded in single and entangled photons, as well as theoretical tools for their measurement and certification. We outline the main outstanding challenges for theory and each experimental degree-of-freedom, identifying promising future directions of research that may enable these to be overcome. We end by discussing interconnections and shared challenges centered around their distribution, measurement, and manipulation, with a view towards their integration into next-generation quantum technology platforms and applications.
Quantum teleportation is a useful quantum information technology to transmit quantum states between different degrees of freedom. Here we report a quantum state transfer experiment in the linear optical system, transferring a single-photon state in the polarization degree of freedom (DoF) to another photon in the orbital angular momentum (OAM) quantum state via a biphoton OAM entangled channel. Our experimental method is based on quantum teleportation technology. The differences between ours and the original teleportation scheme is that the transfer state is known in ours, and our method is for different particles with different DoFs, while the original one is for different particles with the same DoF. In addition, our present experiment is implemented with a high Bell efficiency since each of the four hybrid-entangled Bell states can be discriminated. We use six states of poles of the Bloch sphere to test our experiment, and the fidelity of the quantum state transfer is $91.8\ifmmode\pm\else\textpm\fi{}1.3%$.
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Photons provide low-noise quantum systems which are ideal for the fundamental studies of the quantum world and for developing new quantum technologies which promise to transform the way we process, transmit and acquire information. The development of the eld of quantum information processing, broadly dened, represents one of the most important scientic and technical challenges of the 21st Century. Photons have been used in demonstrations of basic quantum logic, secure communication tasks, precision measurements and the fundamental studies of quantum mechanics. In order to apply these systems and technologies in an ever increasing scale, it is necessary to develop new methods for eciently manipulating the quantum state of light. This is one of the main goals of this study which experimentally demonstrates new techniques for realising multi-qubit logic gates as well as a new method for amplifying quantum states of light noiselessly.