Efficient High-Dimensional Entangled State Analyzer with Linear Optics

Quantum, vol. 9, pp. 1711

Abstract

The use of higher-dimensional photonic encodings (qudits) instead of two-dimensional encodings (qubits) can improve the loss tolerance and reduce the computational resources of photonic-based quantum information processing. To harness this potential, efficient schemes for entangling operations such as the high-dimensional generalization of a linear optics Bell measurement will be required. We show how an efficient high-dimensional entangled state analyzer can be implemented with a linear optics interferometer and auxiliary photonic states. The degree of entanglement of the auxiliary state is much less than in previous protocols as quantified by an exponentially smaller Schmidt rank. In addition, the auxiliary state only occupies a single spatial mode, allowing it to be generated deterministically from a single quantum emitter coupled to a small qubit register. The reduced complexity of the auxiliary states results in a high robustness to imperfections and we show that auxiliary states with fidelities above 0.9 for qudit dimensions 4 can be generated in the presence of qubit error rates on the order of 10%. This paves the way for experimental demonstrations with current hardware.

Authors 3

1. Niv Bharos

   QuTech · Delft University of Technology

   Affiliation as printed

   QuTech, Delft University of Technology, Delft 2628CJ, Zuid-Holland, The Netherlands

2. Liubov A. Markovich Aachen $\langle \text{aQa}^\text{L} \rangle$ Applied Quantum Algorithms Leiden Instituut-Lorentz

   Leiden University

   Affiliation as printed

   $\langle \text{aQa}^\text{L} \rangle$ Applied Quantum Algorithms Leiden, The Netherlands

   Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands

3. Johannes Borregaard

   Harvard University · QuTech · Delft University of Technology

   Affiliation as printed

   Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA

   QuTech, Delft University of Technology, Delft 2628CJ, Zuid-Holland, The Netherlands