Measurements in two bases are sufficient for certifying high-dimensional entanglement

By J. Bavaresco, Natalia Herrera Valencia, Claude Klöckl, Matej Pivoluska, P. Erker, Nicolai Friis, Mehul Malik, Marcus Huber. Nature Physics, 2017

209 citations recorded by the source corpus.

High-dimensional encoding of quantum information provides a way of transcending the limitations of current approaches to quantum communication, which are mostly based on the entanglement between qubits—two-dimensional quantum systems. One of the central challenges in the pursuit of high-dimensional alternatives is ascertaining the presence of high-dimensional entanglement within a given high-dimensional quantum state. In particular, it would be desirable to carry out such entanglement certification without resorting to inefficient full state tomography. Here, we show how carefully constructed measurements in two bases (one of which is not orthonormal) can be used to faithfully and efficiently certify bipartite high-dimensional states and their entanglement for any physical platform. To showcase the practicality of this approach under realistic conditions, we put it to the test for photons entangled in their orbital angular momentum. In our experimental set-up, we are able to verify 9-dimensional entanglement for a pair of photons on a 11-dimensional subspace each, at present the highest amount certified without any assumptions on the state.Certification of high-dimensional entanglement is required for improved quantum communication protocols, and is now shown to be achievable in an efficient manner by measuring quantum states twice in two different bases.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/3eb936a454835d3b6723f74558166f39c43c2ecb

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Citations in the corpus

Chip-to-chip quantum teleportation and multi-photon entanglement in silicon (2019, methodology): “The twobasis measurements can also be used to efficiently lower bound the state fidelity [35], and results are provided in Fig.”
High‐Dimensional Quantum Communication: Benefits, Progress, and Future Challenges (2019, background): “[186] a new way to certify the dimensions of entangled qudits with carefully constructed measurements in two bases.”
Entanglement certification from theory to experiment (2018, methodology): “More recently, an assumptionfree entanglement witness was implemented with SLMs certifying dent = 9 OAM-entanglement with only two measurement settings [115].”