Calibration of Trapped-Ion Systems

This project was conducted at the Institute for Quantum Computing, Baidu Inc., in collaboration with Dr. Jingbo Wang. The work has culminated in the development of three patents:

  • C. Huang and J. Wang, "Ion trap chip parameter correction method and device, electronic equipment and medium," Chinese Patent CN117454997, Granted 2025.
  • J. Wang and C. Huang, "Ion trap chip parameter determining method and device, electronic equipment and medium," Chinese Patent CN117371547, Granted 2024.
  • J. Wang and C. Huang, "Ion trap chip parameter calibration method and device, electronic equipment and medium," Chinese Patent CN117494829, Granted 2024.

Introduction

Trapped-ion quantum computing, as one of the earliest platforms to demonstrate quantum computation, has been under development for over 30 years. From the initial demonstration of Schrödinger's cat states to the creation of fully connected qubit chips, the trapped-ion platform has consistently shown great potential as a quantum computing hardware solution. The fundamental principles of trapped-ion quantum computing are as follows:

  1. Qubit encoding: Individual ions are used as qubits by leveraging different energy levels within the ion. These levels often result from orbital splitting, forming fine or hyperfine structures. The ion's internal energy levels are typically rich and non-equidistant, making them suitable for qubit encoding.
  2. Qubit manipulation: By carefully selecting specific laser frequencies and applying precise laser techniques, the trapped-ion system enables the preparation of initial quantum states, the manipulation of qubit states, and the measurement of quantum states.
  3. Qubit coupling: Since ions are charged particles, they interact with one another through Coulomb forces, which include long-range interaction terms. This natural property allows ions in a quantum chip to form a fully connected network. Specially tailored laser or microwave techniques can be used to mediate interactions between any pair of qubits, granting the trapped-ion platform its inherent full-connectivity feature.

Physical process

Vibration modes

Two-level approximation and Raman process

single-qubit gates

Two-qubit gates


Calibration

Motivation

Calibration of phonon frequency

Calibration of Lamb-Dicke parameters


Links