Title: How to perfect a matterwave "gate", and why

Speaker: Saijun Wu Fudan University

Time: 10:00 am, Mar.25th，2024

Venue: C109, New Science Building

Abstract: In real-world applications, quantum systems are controlled by inherently imperfect classical resources. Nevertheless, for discrete "qubits" or "spins," nearly perfect controls can be achieved by harnessing the geometric phases of the few-level evolution. The same technique can be applied to matterwaves, provided there exists a timescale that allows for the simplification of continuous motion into few-level dynamics. The key, of course, is to perform the error-resilient control within that timescale. In this talk, I will discuss our efforts toward perfecting the control of matterwaves in two inter-related research fronts. First, we use shaped picosecond pulses to control the dipolar motion of the valence electron in atoms, thereby steering the collective spontaneous emission, through which microscopic optical dynamics are unveiled in the far field. Second, we use shaped nanosecond pulses to precisely control the spinor matterwaves in atom interferometry with a focused laser. In addition to implications in precision measurements, I will discuss how the laser-technology-driven optimal quantum control techniques may help to shift the research paradigm in atomic physics and quantum optics in the future.

[1] Ji Lingjing et al, Phys. Rev. Lett. 131, 253602 (2023).

[2] Ma Yudi et al, Phys. Rev. Applied, 20, 024041 (2023).

[3] Qiu Liyang et al, PRX Quantum, 3, 040301 (2022).