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Logo: Institut für Quantenoptik/Leibniz Universität Hannover
Logo Leibniz Universität Hannover
Logo: Institut für Quantenoptik/Leibniz Universität Hannover
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One of the underlying principles of general relativity is the Einstein equivalence principle. It can directly be probed by measuring the free fall acceleration of any two test objects with different internal composition and masses. Precise quantum measurements can be achieved
by simultaneous atom interferometry of a mixed species Bose-Einstein condensate (BEC). To increase the precision of such an experiment the enclosed space-time path of the interferometry sequence has to be maximized which demands a weightless environment.

This possibility is given on a sounding rocket which stays several minutes in microgravity. Therefore the MAIUS project/collaboration develops miniaturized technologies qualified for the use on rocket missions.

On 23.01.2017 MAIUS-1 successfully launched and created the first BEC in space (see MAIUS-1). Thus the feasibility of atom-optical experiments in space has been shown and the next step towards probing the equivalence principle can be taken.


The project MAIUS-2 adds a second atom species for sequential creation of BECs consisting of Rb-87 and K-41 in space and plans to realize a Raman based atom interferometer.  In the last step the experiment will be extended to simultaneous creation of dual species BECs on MAIUS-3.

The new system has been commissioned and qualified on ground and first results on ground-based cooling of alkaline atoms have been achieved. The next steps towards the second launch are the creation and observation of BECs of Rb-87 and K-41.

Experimental Setup

The experimental setup contains the physics package, a laser system, electronics and a battery module

Physics Package

The Physics Package consists of a double MOT-design. The 2D+-MOT guarantees a high atom flux while also having a high repetition rate. The 3D-MOT contains an atom chip which generates various magnetic field configurations. The vacuum system has a pressure of <10-10 mbar generated by two titanium sublimation
pumps and one ion getter pump. Two ovens are mounted to the vacuum chamber which act as sources for potassium and rubidium atoms.

Electronics module

The electronics module contains several pcb boards that are self deigned to fulfill the requirements of the operation on a sounding rocked and offer the accuracy and reliability to control a precision experiment.

All parts of the electronics module are connected with a special bus-system that was develop especially for miniaturized high performance diode laser systems and their support equipment to enable atom optical experiments in microgravity environments like drop towers (ZARM) and sounding rockets. (See also Lasus)

Laser system

There are two laser systems, a flight laser system and a groundbased laser system. The flight laser system is used for final measurements and the rocket launch. It is zerodur-based with narrow-banded external cavity diode lasers (ECDL) and it is designed for cooling, repumping, detection and Raman double diffraction interferometry for potassium and rubidium. Additionally there is a 1064 nm dipole trap to get access to interspecies Feshbach resonances. The groundbased laser system is a transportable, modular and robust ECDL setup for groundbased experiments and commissioning of physics package.


Bachelor- und Masterarbeiten

Wir bieten Bachelor- und Masterarbeiten zu vielfältigen Themen an. Interessierte und motivierte Studierende können sich dazu bei uns melden! Kontakt: Baptist Piest (piestiqo.uni-hannover.de)

  • Aufbau eines Rubidium-Lasersystems:

    • Für das Rubidium-Bodenlasersystem sollen zwei weitere Module aufgebaut werden. Die Module unterscheiden sich hinsichtlich ihrer Verwendung im Experiment. Eines dient als Quelle des Laserlichts für die 2D+-MOT  und die Raman-Interferometrie. Das andere wird für den Betrieb der 3D-MOT und Detektion benötigt.

  • Tests neuer Strahlaufweitungsoptiken für die 2D-MOT

    • Es sollen neue Ansätze simuliert und getestet werden, die bisher verwendete Strahlaufweitungsoptik der 2D-MOT zu verbessern. Die neuen Konzepte sollen simuliert, aufgebaut und direkt an den Atomen getestet werden.

  • Charakterisierung und Optimierung der Zwei-Spezies 2D+- und 3D-MOT

    • Um mit einer möglichst großen Anzahl von Atomen die weiteren Kühlschritte hin zur Bose-Einstein-Kondensation zu beginnen, müssen sowohl die 2D+- als auch 3D-MOTs jeweils für Kalium- und Rubidiumatome optimiert und charakterisiert werden. Besonderes Augenmerk soll dabei auf den simultanen Betrieb als Zwei-Spezies-MOT gelegt werden.