연사: Michał Lipka from University of Basel

일시: 2026년 09월 21일, 3:00 – 4:00pm

장소: 연구협력관 B1 Jupiter 세미나룸

세미나 명: “Spatially Split Spin-Squeezed Bose-Einstein Condensates for Multiparameter Metrology and Clock Interferometry”

초록: 

We present a versatile atom-chip platform for multiparameter quantum sensing based on a two-component 87Rb Bose–Einstein condensate. 

Our setup enables the generation of collective spin-squeezed states via one-axis twisting dynamics, followed by the coherent spatial splitting of the condensate into multiple individually addressable clouds. 

This splitting process successfully preserves both the internal (intra-cloud) and distributed (inter-cloud) many-body entanglement. 

Recently, we utilized this capability to create an array of up to three entangled atomic sensors, each constituting several hundreds of atoms. 

By optimizing the measurement protocol to fully exploit the inter-sensor entanglement, we demonstrated the simultaneous estimation of multiple local parameters, achieving quantum gains of up to 3.6 dB beyond the standard quantum limit [1]. 

These results establish mesoscopic condensates on atom chips as a powerful experimental testbed for multiparameter quantum metrology and fundamental studies of steering and non-locality [2,3]. 

Furthermore, our architecture holds great promise for proof of principle studies in quantum clock interferometry. 

The internal degree of freedom of each split cloud acts as a local clock measuring the phase evolution between the 2 hyperfine levels. 

Together with the ability to split, independently manipulate, and coherently recombine the entangled ensembles, it provides the essential tools for future studies exploring entanglement-enhanced clock interferometry, which has been proposed as a tool for measuring General Relativity effects in a laboratory setting [4,5]. 

In this contribution, we will detail our recent multiparameter sensing results and outline the roadmap for future experiments in clock interferometry with our platform.  

References

[1] Y. Li, L. Joosten, Y. Baamara, P. Colciaghi, A. Sinatra, P. Treutlein, and T. Zibold, Multiparameter estimation with an array of entangled atomic sensors, Science 391, 6783 (2026).

[2] L. Pezzè, A. Smerzi, M. K. Oberthaler, R. Schmied, and P. Treutlein, Quantum metrology with nonclassical states of atomic ensembles, Rev. Mod. Phys. 90, 035005 (2018).

[3] P. Colciaghi, Y. Li, P. Treutlein, and T. Zibold, Einstein-Podolsky-Rosen Experiment with Two Bose-Einstein Condensates, Phys. Rev. X 13, 021031 (2023).

[4] A. Roura, Gravitational redshift in quantum-clock interferometry, Phys. Rev. X 10, 021014 (2020).

[5] M. Zych, F. Costa, I. Pikovski, and Č. Brukner, Quantum interferometric visibility as a witness of general relativistic proper time, Nat. Commun. 2, 505 (2011).