Freiburg 2024 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 37: Poster III

Q 37.42: Poster

Wednesday, March 13, 2024, 17:00–19:00, Tent B

Graph states generation from one and two atoms in an optical cavity — Philip Thomas, •Leonardo Ruscio, Olivier Morin, and Gerhard Rempe — Max-Planck-Institut of Quantum Optics, Hans-Kopfermann-Straße 1, 85748 Garching

Given the importance of multiphoton graph states in quantum computation and communication, their experimental demonstration is an important step towards the realization of e.g measurement based quantum computation. In our work we used single rubidium atoms trapped in the center of a Fabry-Perot cavity to grow photonic graph states. With a single atom we implemented a deterministic protocol to efficiently generate Greenberger-Horne-Zeilinger (GHZ) states and linear cluster states up to 14 and 12 photons respectively, with fidelity greater than of 76(6)% and 56(4)% [1]. Thanks to an overall single photon efficiency of 43% we collected these large states at a rate of about one coincidence per minute. Using two atoms we demonstrated the generation of more complex graphs, such as tree and ring states, exploiting an entangling mechanism based on the simultaneous emission and subsequent interference of two photons in the cavity mode [2]. Starting with two independent GHZ states we produced a tree composed of eight qubits with a lower bound fidelity of 69%. Furthermore, fusing a linear cluster states with two entangling operations we also obtained rings of six and eight qubits.

[1] P. Thomas et al., Nature 608, 677*681 (2022).

[2] P. Thomas et al., Under review (2024)

Keywords: CQED; Graph States; Cluster States; GHZ states; Single Atoms