Freiburg 2024 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 56: Poster VII

Q 56.10: Poster

Thursday, March 14, 2024, 17:00–19:00, KG I Foyer

Analytical theory of double Bragg atom interferometers — •Rui Li¹, Klemens Hammerer², and Naceur Gaaloul¹ — ¹Leibniz University Hanover, Institute for quantum optics, Hannover, Germany — ²Leibniz University Hanover, Institute for theoretical physics, Hannover, Germany

In this talk, we will provide some new physical insights into a commonly used tool in atom interferometry, namely the double Bragg diffraction (DBD). After reviewing the traditional treatment of DBD with rotating wave approximations and its limitations, we derive an effective two-level-system (TLS) Hamiltonian via Magnus expansion for describing the so-called *quasi-Bragg regime* where most light-pulse atom interferometers are operating. With this effective TLS Hamiltonian, we systematically study the effects of polarization error and AC-Stark shift due to second-order process on the efficiency of double-Bragg beam-splitters. Furthermore, we show that effects of Doppler broadening can be easily included by extending our TLS description to a three-level-system description. Finally, we design an optimal beam-splitter based on our effective theory via a time-dependent detuning and show its robustness against polarization error and asymmetric beam-splitting due to Doppler effect.

Keywords: Atom interferometry; Double bragg diffraction; Doppler broadening; Polarization error effect; Magnus expansion