6 research outputs found
Testing the universality of free fall with rubidium and ytterbium in a very large baseline atom interferometer
We propose a very long baseline atom interferometer test of Einstein's
equivalence principle (EEP) with ytterbium and rubidium extending over 10m of
free fall. In view of existing parametrizations of EEP violations, this choice
of test masses significantly broadens the scope of atom interferometric EEP
tests with respect to other performed or proposed tests by comparing two
elements with high atomic numbers. In a first step, our experimental scheme
will allow reaching an accuracy in the E\"otv\"os ratio of .
This achievement will constrain violation scenarios beyond our present
knowledge and will represent an important milestone for exploring a variety of
schemes for further improvements of the tests as outlined in the paper. We will
discuss the technical realisation in the new infrastructure of the Hanover
Institute of Technology (HITec) and give a short overview of the requirements
to reach this accuracy. The experiment will demonstrate a variety of techniques
which will be employed in future tests of EEP, high accuracy gravimetry and
gravity-gradiometry. It includes operation of a force sensitive atom
interferometer with an alkaline earth like element in free fall, beam splitting
over macroscopic distances and novel source concepts
Interacting quantum mixtures for precision atom interferometry
We present a source engineering concept for a binary quantum mixture suitable as input for differential, precision atom interferometry with drift times of several seconds. To solve the non-linear dynamics of the mixture, we develop a set of scaling approach equations and verify their validity contrasting it to the one of a system of coupled Gross-Pitaevskii equations. This scaling approach is a generalization of the standard approach commonly used for single species. Its validity range is discussed with respect to intra- and inter-species interaction regimes. We propose a multi-stage, non-linear atomic lens sequence to simultaneously create dual ensembles with ultra-slow kinetic expansion energies, below 15 pK. Our scheme has the advantage of mitigating wave front aberrations, a leading systematic effect in precision atom interferometry
Design of a dual species atom interferometer for space
Atom interferometers have a multitude of proposed applications in space
including precise measurements of the Earth's gravitational field, in
navigation & ranging, and in fundamental physics such as tests of the weak
equivalence principle (WEP) and gravitational wave detection. While atom
interferometers are realized routinely in ground-based laboratories, current
efforts aim at the development of a space compatible design optimized with
respect to dimensions, weight, power consumption, mechanical robustness and
radiation hardness. In this paper, we present a design of a high-sensitivity
differential dual species Rb/Rb atom interferometer for space,
including physics package, laser system, electronics and software. The physics
package comprises the atom source consisting of dispensers and a 2D
magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap
based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein
condensate (BEC) creation and interferometry, the detection unit, the vacuum
system for mbar ultra-high vacuum generation, and the
high-suppression factor magnetic shielding as well as the thermal control
system. The laser system is based on a hybrid approach using fiber-based
telecom components and high-power laser diode technology and includes all laser
sources for 2D-MOT, 3D-MOT, ODT, interferometry and detection. Manipulation and
switching of the laser beams is carried out on an optical bench using Zerodur
bonding technology. The instrument consists of 9 units with an overall mass of
221 kg, an average power consumption of 608 W (819 W peak), and a volume of 470
liters which would well fit on a satellite to be launched with a Soyuz rocket,
as system studies have shown.Comment: 30 pages, 23 figures, accepted for publication in Experimental
Astronom
STE-QUEST - Test of the Universality of Free Fall Using Cold Atom Interferometry
In this paper, we report about the results of the phase A mission study of the atom
interferometer instrument covering the description of the main payload elements, the
atomic source concept, and the systematic error sources
Theoretical study of the preparation of quantum degenerate mixtures for precision atom interferometry
In dieser Arbeit werden quantenentartete Gemische auf ihre Eigenschaften als Quellen für Präzisionsatominterferometer zum Test des Einsteinschen Äquivalenzprinzips untersucht. Um die notwendige Auflösung zu erreichen, sollen die Interferometriezyklen auf mehrere Sekunden ausgedehnt werden. Die bekannten Hauptbeiträge an systematischen Effekten, die bei realistischen Aufbauten auftreten, sind hierbei berücksichtigt, und für einige werden Strategien zur Unterdrückung präsentiert. Die Gemische die hier betrachtet werden, sind Bose-Einstein-Kondensate aus 87Rb/85Rb und 87Rb/41K. Eine simultane Absenkung der Expansionsraten beider Komponenten in den Temperaturbereich von weniger als 100 pK ist notwendig, um einerseits freie Entwicklungszeiten der Kondensate von 10 s zu ermöglichen, und andererseits systematische Fehler zum Beispiel verursacht durch die atomare Bewegung in den Wellenfronten der Lichtfelder zu unterdrücken. Um diese Anforderungen erfüllen zu könnnen, wurde die Rolle der Wechselwirkung der Teilchen untereinander betrachtet, die von ihrer einfachen Durchstimmbarkeit mit Hilfe von Feshbach-Resonanzen profitiert. Neben der Manipulierbarkeit der Wechselwirkung wurden Delta-Kicks zur Kollimation untersucht, durch die der Einfluss der führenden systematischen Fehler unterdrückt wird. Neben dem oben genannten Gemisch wurden auch die Gemische 87Rb/39K und 87Rb/170Yb untersucht. Das 87Rb/87K-Gemisch wurde als Kandidat für Hochpräzisionsatominterferomtrie in Mikrogravitation identifiziert. Das Yb-basierte Gemisch hat den vorteil, dass die Wechselwirklung ohne zusätzliche Feshbachfelder durchgeführt werden kann. Für die Delta-Kicks wurde eine Vielzahl an Fallengeometrien untersucht, wie etwa die Dipolfalle, chip-basierte Potentiale, sowie das TOP-Fallenpotential (engl.: Time-Orbiting-Potential), um Majorana-Verluste zu verhindern. Die Berechnungen wurden mit Hilfe der Gross Pitaevskii Gleichung und Skalierungstheorie vorgenommen