Implementation of Single-Qubit Quantum Gates Based on a Microwave Transition in a Single Rubidium Atom in an Optical Dipole Trap

• Published in: Journal of experimental and theoretical physics 2021-03, Vol.132 (3), p.341-353
• Main Authors: Beterov, I. I., Yakshina, E. A., Tretyakov, D. B., Entin, V. M., Al’yanova, N. V., Mityanin, K. Yu, Ryabtsev, I. I.
• Format: Article
• Language: English
• Subjects: Atoms; Classical and Quantum Gravitation; Dipoles; Elementary Particles; Fluorescence; Laser pumping; Molecules; Optical pumping; Optics; Oscillations; Particle and Nuclear Physics; Physics; Physics and Astronomy; Quantum Field Theory; Qubits (quantum computing); Radiation; Relativity Theory; Resonance fluorescence; Rubidium; Solid State Physics; Vacuum chambers
• ISSN: 1063-7761; 1090-6509
• DOI: 10.1134/S1063776121030134

The results of experiments on the implementation of single-qubit quantum gates with a single 87 Rb atom in an optical dipole trap with a wavelength of 850 nm are presented. The trap is formed by a long focal-length objective lens located outside the vacuum chamber of a magneto-optical trap. An atom is detected using a resonance fluorescence signal with an sCMOS video camera. The experiments involved the trapping and confinement of a single atom at times up to 50 s, optical pumping by polarized laser radiation, microwave transitions between two hyperfine sublevels of the ground state, and the measurement of the quantum state of the atom by pushing it from the trap. Rabi oscillations are observed during the “clock” microwave transition 5 S 1/2 ( F = 2, M F = 0) → 5 S 1/2 ( F = 1, M F = 0) between two operating qubit levels at a frequency of up to 4.2 kHz, a contrast of up to 95%, and a coherence time of up to 3 ms. These oscillations correspond to the implementation of two basic single-qubit quantum operations (Hadamard gate, NOT gate) from various initial qubit states with an average fidelity of 95.2 ± 3%.