Quantum gates with Rydberg atoms

Abstract

In the context of quantum computing based on neutral atoms we study the implementation of quantum gates, the fundamental logic operations of quantum circuits. In particular, we focus on the strong, long-range interactions provided by Rydberg states. First, single-qubit operations are modelled using Rabi oscillations and Maxwell-Bloch equations, characterizing decoherence and error sources. Next, we introduce the Rydberg blockade mechanism to simulate conditional quantum dynamics, specifically implementing a two-qubit controlled-NOT (CNOT) gate. By introducing an error model accounting for spontaneous emission and pulse fluctuations, we achieve a simulated gate fidelity of 95.46%, which is then optimized to 96.15% by tuning the parameters. Finally, these operations are integrated into a superdense coding circuit to demonstrate a practical quantum communication protocol.