May 9, 2024

Breaking Quantum Boundaries: A New Theory for Periodically Driven QD-Cavity Hybrid Systems

Researchers developed a new reaction theory that deals with the cavity as a part of the driven system, as opposed to the existing theory. Utilizing this theory, they successfully simulated and interpreted the signals in the experiment, and further examined the case of a two-DQD-cavity hybrid system under periodic driving..
This research study blazed a trail for understanding occasionally driven QD-cavity hybrid systems. The theoretical technique established is not only applicable to hybrid systems with various coupling strength however also can be extended to multiqubit systems..
Reference: “Probing Two Driven Double Quantum Dots Strongly Coupled to a Cavity” by Si-Si Gu, Sigmund Kohler, Yong-Qiang Xu, Rui Wu, Shun-Li Jiang, Shu-Kun Ye, Ting Lin, Bao-Chuan Wang, Hai-Ou Li, Gang Cao and Guo-Ping Guo, 9 June 2023, Physical Review Letters.DOI: 10.1103/ PhysRevLett.130.233602.

In previous research studies, the team utilized a high-impedance super-conducting resonant cavity to execute the strong coupling of the QD-cavity hybrid system. Based on this strong coupling, the team even more studied the circuit quantum electrodynamics (cQED) of the periodically driven, strongly paired hybrid system.
By probing the microwave response signal of the DQD-cavity hybrid system under routine driving, they found that the existing theory for dispersive cavity readout stops working due to the enhancement of the coupling strength.

Scientists have actually established a new action theory for strongly combined, multiqubit systems. This advancement addresses the difficulties dealt with in understanding regularly driven QD-cavity hybrid systems.
A team led by Prof. Guo Guoping and Prof. Cao Gang from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS), collaborated with Sigmund Kohler from the Materials Science Institute of Madrid to create a reaction theory appropriate for highly coupled and multiqubit systems. Their research has just recently been released in the journal Physical Review Letters.
Semiconductor quantum dot (QD) strongly combined to microwave photons is the essential to examine light-matter interactions. In previous studies, the group utilized a high-impedance super-conducting resonant cavity to implement the strong coupling of the QD-cavity hybrid system. Based on this strong coupling, the team even more studied the circuit quantum electrodynamics (cQED) of the periodically driven, strongly coupled hybrid system.
In this research study, the scientists initially prepared a composite device of a high-impedance resonant cavity incorporated with 2 double quantum dots (DQD). By penetrating the microwave response signal of the DQD-cavity hybrid system under regular driving, they discovered that the existing theory for dispersive cavity readout fails due to the improvement of the coupling strength.