# The 27th International Conference on Atomic Physics

17-22 July 2022
Royal Conservatory of Music, Toronto
America/Toronto timezone

## Shear interferometry in microgravity with atomic ensembles in the picokelvin regime

20 Jul 2022, 17:00
1h 30m
Hart House (Hart House)

### Hart House

#### Hart House

7 Hart House Cir, Toronto, ON M5S 3H3
Poster presentation Precision measurement and tests of fundamental physics

### Description

Atom interferometry as a tool for precision measurements opens up a broad field of application: from testing fundamental physics to geodesy or navigation. Since the sensitivity of an atom interferometer scales quadratically with the interrogation time, operating on a microgravity platform is highly beneficial. Extended times of flight of several seconds require low expansion rates of the atomic ensemble, which can be achieved with magnetic lensing, also known as delta-kick collimation. To pave the way for space-borne atom interferometry, the QUANTUS-2 experiment was developed. This high-flux rubidium BEC machine, based on the atom chip technology, is designed to operate at the 110m high ZARM drop tower in Bremen, Germany, where microgravity times of 9.7$\,$s can be reached.
In this contribution, a quadrupole-mode enhanced magnetic lens is presented to achieve a three-dimensional collimated BEC. The resulting atomic ensemble features an ultra-low internal 3D kinetic energy of $\frac{3}{2} k_B \cdot$ 38$\,$pK and a high signal to noise ratio even after 2$\,$s time of flight [1]. The novel application of a Ramsey sequence as a shear interferometer consisting of two successive double Bragg beam splitter pulses enables us to investigate the divergence of the BEC and possible magnetic lens imperfections. Additionally, the spatially resolved velocity spread can be deduced based on the recorded spatial interferometry pattern. The demonstrated atom interferometry with picokelvin ensembles provides the basis for future interferometry measurements on long time scales with the aim of unprecedented precision.
This project is supported by the German Space Agency DLR with funds provided by the Federal Ministry for Economic Affairs and Energy under grant number DLR 50WM1952-1957.

[1] C. Deppner, W. Herr, M. Cornelius, et al. "Collective-mode enhanced matter-wave optics." Physical Review Letters 127.10, 100401 (2021)

Presenter name Merle Cornelius

### Primary authors

Merle Cornelius (ZARM, University of Bremen) Julia Pahl (Humboldt University of Berlin) Peter Stromberger (Johannes Gutenberg University Mainz) Laura Pätzold (University of Bremen) Dorthe Leopoldt (Leibniz University Hannover) Waldemar Herr (Leibniz University Hannover) Sven Herrmann (University of Bremen) Patrick Windpassinger (Johannes Gutenberg University Mainz) Christian Schubert (Leibniz University Hannover) Markus Krutzik (Humboldt University of Berlin) Ernst M. Rasel (Leibniz University Hannover) Claus Lämmerzahl (University of Bremen)

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