[論文レビュー] Trapped ion qubit and clock operations with a visible wavelength photonic coil resonator stabilized integrated Brillouin laser

Nitesh Chauhan, Christopher Caron+6 more|arXiv (Cornell University)|Feb 26, 2024

Mechanical and Optical Resonators被引用数 11

ひとこと要約

この論文は、可視波長ブリルアンレーザーを統合Si3N4 3メートルコイル共振腔に安定化した Sr+ トラップイオンを用いたチップスケールの光 clock および qubit 操作を示し、99% SPAM、6 kHz の線幅、5×10^-13/√τ の 1 s 安定性で 60 μs Ramsey コヒーレンスを達成している。

ABSTRACT

Integrating precise, stable, ultra-low noise visible light lasers into atomic systems is critical for advancing quantum information sciences and improving scalability and portability. Trapped ions are a leading approach for high-fidelity quantum computing, high-accuracy optical clocks, and precision quantum sensors. However, current ion-based systems rely on bulky, lab-scale precision lasers and optical stabilization cavities for optical clock and qubit operations, constraining the size, weight, scalability, and portability of atomic systems. Chip-scale integration of ultra-low noise lasers and reference cavities operating directly at optical clock transitions and capable of qubit and clock operations will represent a major transformation in atom and trapped ion-based quantum technologies. However, this goal has remained elusive. Here we report the first demonstration of chip-scale optical clock and qubit operations on a trapped ion using a photonic integrated direct-drive visible wavelength Brillouin laser stabilized to an integrated 3-meter coil-resonator reference cavity and the optical clock transition of a $^{88}$Sr$^+$ ion trapped on a surface electrode chip. We also demonstrate for the first time, to the best of our knowledge, trapped-ion spectroscopy and qubit operations such as Rabi oscillations and high fidelity (99%) qubit state preparation and measurement (SPAM) using direct drive integrated photonic technologies without bulk optic stabilization cavities or second harmonic generation. Our chip-scale stabilized Brillouin laser exhibits a 6 kHz linewidth with the 0.4 Hz quadrupole transition of $^{88}$Sr$^+$ and a self-consistent coherence time of 60 $μ$s via Ramsey interferometry on the trapped ion qubit. Furthermore, we demonstrate the stability of the locked Brillouin laser to 5$ imes10^{-13}/ \sqrtτ$ at 1 second using dual optical clocks.

研究の動機と目的

• Motivate integration of ultra-low-noise visible lasers into trapped ion systems for portability and reliability.
• Demonstrate chip-scale stabilization of a 674 nm SBS laser to a 3-meter coil resonator and absolute lock to a Sr+ optical clock transition.
• Show complete trapped-ion spectroscopy, high-fidelity SPAM, Rabi oscillations, and Ramsey coherence using integrated photonic technologies.

提案手法

• Use a direct-drive 674 nm SBS laser integrated on a silicon nitride platform.
• Stabilize the SBS laser to a photonic integrated 3-meter coil resonator reference cavity (high Q, low loss).
• Further stabilize to the 674 nm Sr+ optical clock transition via a clock protocol interleaved with qubit operations.
• Interleave two independent optical clocks to measure absolute stability and drift.
• Characterize laser performance via trapped-ion spectroscopy, Ramsey interferometry, and Rabi oscillations.

実験結果

リサーチクエスチョン

• RQ1 Can a chip-scale Brillouin laser stabilized to an integrated coil cavity support high-fidelity trapped-ion qubit operations?
• RQ2 What are the achievable linewidth, coherence, and stability when stabilizing a visible-wavelength laser to an integrated coil resonator and Sr+ clock transition?
• RQ3 Does interleaving clock stabilization with qubit operations enable robust, portable trapped-ion quantum sensing and timing?
• RQ4 What SPAM fidelity and spectroscopy resolution are possible with fully integrated photonic stabilization on a trapped-ion chip?

主な発見

• Demonstrated 12 Hz free-running linewidth of the SBS laser; 580 Hz ILW when locked to the coil resonator; 6 kHz linewidth when locked to the ion clock transition.
• Achieved 99% SPAM fidelity for qubit state preparation and measurement using coil+ion stabilized laser, with SBS+coil+ion enabling higher coherence.
• Ramsey coherence time extended from 33 μs (coil+ion) to 60.5 μs (SBS+coil+ion).
• Absolute laser stability within 300 Hz when locked to the Sr+ optical clock transition; long-term stability 5×10^-13/√τ at 1 s and ±4 kHz drift over a minute.
• Demonstrated interleaved clock and qubit operations on a cm-scale chip, enabling portable trapped-ion quantum sensing and clocks.