内容：

Mediating interactions and generating entanglement between separated quantum elements is of fundamental interest as well as a crucial step for scalable quantum technology. On one hand, the ability to entangle qubits that are remotely located enables a modular approach to scale up the quantum circuits with high connectivity. On the other hand, it raises an intriguing physics question: can we create quantum connections that could lead to entanglement between different quantum degrees of freedom? In this talk, I will discuss our efforts at Pfaff lab to advance the connectivity between different quantum elements, using circuit QED platform. For one, we have realized two-qubit gates with high fidelities through detachable and reconfigurable cable connections [1]; this effort is geared towards developing means to scale quantum processors beyond single wafers. Next, we are developing routing schemes that will enable all-to-all connectivity for 'plug & play' connected networks [2]. This could potentially enable the steady-state remote entanglement with a drive-dissipative protocol [3-4]. Finally, I will shift focus to our exploration of hybrid quantum systems, where we couple superconducting qubits with magnetic materials. This novel platform facilitates the detection of magnons at large occupation numbers and enables parametric coupling between the two quantum systems. Such hybrid systems serve as sensitive, high-dynamic-range quantum probes for studying magnetic excitations and their dynamics, offering an exciting pathway to investigate magnon properties within hybrid quantum circuits.

 [1] Mollenhauer, M., Irfan, A., Cao, X., Mandal, S. & Pfaff, W. arXiv:2407.16743 (2024).

[2] Cao, X., Irfan, A., Mollenhauer, M., Singirikonda, K. & Pfaff, W. arXiv:2405.15086 (2024).

[3] Lingenfelter, A. et al. Phys. Rev. X 14, 021028 (2024).

[4] Irfan, A. et al. Phys. Rev. Research 6, 033212 (2024).

人物介绍：

Xi Cao received his Ph.D. from the University of Pittsburgh, where he worked with Prof. Michael Hatridge on quantum measurements with two-mode squeezed light and parametric bath engineering. After his graduation, he moved to the University of Illinois Urbana Champaign and started his post-doc with Prof. Wolfgang Pfaff. His current research interests include distributed modular quantum computing and hybrid quantum systems.