Related Experiment Video
Updated: Sep 11, 2025
05:39
Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform
Published on: August 2, 2019
9.7K
Direct Implementation of High-Fidelity Three-Qubit Gates for Superconducting Processor with Tunable Couplers
Hao-Tian Liu1,2, Bing-Jie Chen1,2, Jia-Chi Zhang1,2
1Institute of Physics, Chinese Academy of Sciences, Beijing National Laboratory for Condensed Matter Physics, Beijing 100190, China.
Physical Review Letters
|August 18, 2025
Summary
Researchers developed a direct three-qubit controlled-controlled-z (ccz) gate for quantum computing. This high-fidelity gate enhances quantum circuit performance and reduces errors compared to traditional methods.
Area of Science:
- Quantum Computing
- Superconducting Circuits
- Quantum Information Science
Background:
- Three-qubit gates are essential for complex quantum computations.
- Direct implementation offers advantages over gate decomposition but faces fidelity challenges.
Purpose of the Study:
- To propose and experimentally demonstrate a high-fidelity direct three-qubit controlled-controlled-z (ccz) gate.
- To showcase its application in quantum algorithms and compare it with decomposed approaches.
Main Methods:
- Utilized a flip-chip superconducting quantum processor with tunable couplers.
- Implemented the direct ccz gate by simultaneously engaging two tunable couplers for three-qubit interactions.
Main Results:
- Achieved an average final state fidelity of 97.94% and a process fidelity of 93.54%.
- Demonstrated lower leakage in direct implementation compared to decomposed gates.
- Successfully applied the ccz gate in a three-qubit Grover search algorithm, enhancing target probability amplitude.
Conclusions:
- The direct ccz gate offers superior performance and fidelity compared to decomposed gates on similar hardware.
- This method facilitates efficient quantum programming and optimization for complex quantum circuits.
Related Concept Videos
01:24Superconductor
1.2K
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a superconductor. In 1911, Heike Kamerlingh Onnes of Leiden University, a Dutch physicist, observed a relation between the temperature and the resistance of the element mercury. The mercury sample was then cooled in liquid helium to study the linear dependence of resistance on temperature. It was observed that, as the temperature decreased, the...
1.2K
01:28Types Of Superconductors
1.1K
A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the only interesting phenomenon as materials reach their transition temperatures. A second effect is the exclusion of magnetic fields. This is known as the Meissner effect. A light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor. High-speed trains that levitate on strong...
1.1K
01:27Biasing of Metal-Semiconductor Junctions
331
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
331
01:08Spin–Spin Coupling Constant: Overview
1.0K
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
1.0K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.1K
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
1.1K
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
1.1K
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
1.1K