Two Qubit Gate:
IonQ는 MS gate, Quantiuum은 ZZ phase gate를 사용한다.
MS gate와 ZZ phase gate는 서로 컴파일을 통해 상호 변환 가능하다.
ionq: hyperfine qubit quantinuum: optical transition qubit
optical qubit이 gate를 구현하기는 더 쉬우나 hyperfine qubit이 fidelity를 더 좋게 가져갈 수 있다. 왜냐하면 hyperfine이 더 정밀하게 컨트롤 가능하기 때문. hyperfine은 ‘*magnetic-field insensitive transition’*을 선택할 수 있기 때문(called clock transition).
| 구분 | Quantinuum | IonQ(before Oxford) | IonQ(after Oxford) |
|---|---|---|---|
| controll way | Laser/Raman | Laser/Raman | Microwave/EQC |
| 1Q gate | Raman Transition | Raman Transition | Microwave |
| 2Q gate | MS gate(optics mediated) | MZ gate(optics mediated) | EQC base microwave gate |
| key | high fidelity and sophisticated control | software reconfigurability | integration of hardware and scalability |
EQC = Electronic Qubit Control
Cirac Zoller PhysRevLett.74.4091.pdf
Quantum computation with ions in thermal motion by Sorensen and Molmer
Trapped-ion quantum logic gates based on oscillating magnetic fields by Oxford Ionics
Trapped-ion two-qubit gates with > 99.99% fidelity without ground-state cooling by Oxford Ionics