Experimental Realization of Multi-ion Sympathetic Cooling on a Trapped Ion Crystal

Area of Science:

• Quantum Information Science
• Atomic Physics
• Quantum Computing

Background:

• Trapped ions are a leading platform for quantum information science.
• Efficient cooling of large ion crystals is essential for quantum computing and simulation.
• Runtime cooling must preserve internal qubit states, necessitating sympathetic cooling.

Purpose of the Study:

• To demonstrate multi-ion sympathetic cooling on long ion chains.
• To optimize cooling ion selection based on collective oscillation modes.
• To achieve near-global Doppler cooling limits by cooling a small ion fraction.

Main Methods:

• Utilizing a narrow cooling beam focused on two adjacent ions within a long ion chain.
• Optimizing the selection of cooling ions by analyzing collective oscillation modes.
• Measuring the cooling efficiency and its proximity to the Doppler cooling limit.

Main Results:

• Successful multi-ion sympathetic cooling of a long ion chain was achieved.
• Cooling effects approached the global Doppler cooling limit.
• Cooling a small fraction of ions proved highly effective.

Conclusions:

• Sympathetic cooling of a small ion fraction is an efficient method for large ion crystals.
• This technique is a critical enabling step for advanced quantum information processing.
• The results pave the way for scalable quantum computing and simulation.