Important Breakthrough in Quantum Precision Measurement with Superconducting Quantum Circuit Systems
TapTechNews August 21, recently, the research group of Yu Dapeng and Xu Yuan from Hefei National Laboratory/Shenzhen International Quantum Research Institute, in conjunction with research teams such as Professor Zou Changling from Hefei National Laboratory/University of Science and Technology of China, has made important breakthrough experimental progress in the field of quantum precision measurement based on superconducting quantum circuit systems.
The joint research team successfully prepared a Fock state with up to 100 photons in a superconducting microwave resonator with a high quality factor, and on this basis, achieved a quantum-enhanced precision measurement technology close to the Heisenberg limit, demonstrating the advantages of large photon Fock states (Fockstates) in high-precision quantum detection, opening up a new path for the development of high-precision quantum measurement technologies.
The relevant research results were published online in the international academic journal Nature Physics (NaturePhysics) on August 20, 2024, under the title Quantum-enhanced metrology with large Fock states.
According to the official introduction of Hefei National Laboratory:
Classic measurement methods are often limited by the constraint of the standard quantum limit, and it is difficult to further improve the measurement accuracy. However, quantum mechanics provides the potential to go beyond this limit, and its measurement accuracy can in principle reach the highest accuracy limit within the framework of quantum mechanics, that is, the Heisenberg limit.
Compared to the standard quantum limit, the measurement accuracy gain is proportional to the square root of the number of system particles. However, in practical applications, to reach the Heisenberg limit, how to effectively manipulate and measure large-scale non-classical quantum states remains an important experimental challenge.
To overcome these difficulties, the joint research team cleverly utilized the large photon number Fock state in a single simple harmonic oscillator or Bose mode to successfully achieve hardware-efficient, high-precision detection beyond the standard quantum limit.
In this research work, the researchers developed a quantum control method for a photon number filter of the Bose mode with the assistance of superconducting qubits, and efficiently prepared a Fock state with up to 100 photons in a superconducting microwave resonator with a high quality factor, far exceeding the previous photon number of the Fock state, refreshing the world record in this field.
On this basis, the researchers fully utilized the quantum characteristics of these non-classical Fock states to achieve high-sensitivity detection of small displacements or phase shift changes of microwave electromagnetic fields. The measurement accuracy gain exceeded the standard quantum limit by up to 14.8 dB, approaching the Heisenberg limit and reaching an international advanced level.
This research work was supported by the Guangdong Provincial Department of Science and Technology, the Shenzhen Municipal Science and Technology Innovation Commission, the National Natural Science Foundation of China, Hefei National Laboratory, etc.
TapTechNews attached paper link:
https://www.nature.com/articles/s41567-024-02619-5