Rydberg-blockade controlled-not gate and entanglement in a two-dimensional array of neutral-atom qubits

By K. Maller, M. Lichtman, T. Xia, Yuan Sun, M. Piotrowicz, A. Carr, L. Isenhower, Mark Saffman. 2015

209 citations recorded by the source corpus.

We present experimental results on two-qubit Rydberg blockade quantum gates and entanglement in a two-dimensional qubit array. Without post selection against atom loss we achieve a Bell state fidelity of $0.73\pm 0.05$, the highest value reported to date. The experiments are performed in an array of single Cs atom qubits with a site to site spacing of $3.8 ~ \mu\rm m$. Using the standard protocol for a Rydberg blockade C$_Z$ gate together with single qubit operations we create Bell states and measure their fidelity using parity oscillations. We analyze the role of AC Stark shifts that occur when using two-photon Rydberg excitation and show how to tune experimental conditions for optimal gate fidelity.

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

View Paper: https://www.semanticscholar.org/paper/13bfe874397e32cb32237fe6c260accd6949bacf

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Citations in the corpus

Quantum simulation and computing with Rydberg-interacting qubits (2020, background): “For the maximally entangled state | Ψ + the parity should oscillate between ± 1 as a function of θ with a period of π , while in practice the amplitude of these oscillations will be | C | 1 83,169,242,243 .”
Quantum computing with atomic qubits and Rydberg interactions: progress and challenges (2016, background): “a) Eye diagram of CNOT gate with and without blockade as a function of the relative phase φ between π/2 pulses on the target qubit from [10].”
Analysis of imperfections in the coherent optical excitation of single atoms to Rydberg states (2018, methodology): “Recent experimental efforts have shown an improvement in the fidelities of two-qubit gates [25,26], but they still remain below their theoretically predicted intrinsic fidelities [27,28] as compared to other experimental platforms, such as trapped ions [29,30] or superconducting qubits [31– 33].”
Experimental investigations of dipole–dipole interactions between a few Rydberg atoms (2016, methodology): “Detailed theoretical investigations of the measured fidelities [76, 94] seem to indicate that the limitations are mainly technical, and therefore could be overcome.”