Materiewelleninterferenzen im Weltraum

Hochpräzise Atominterferometrie mit Bose-Einstein-Kondensaten hat das Potential Tests fundamentaler Physik mit bisher unerreichter Genauigkeit durchzuführen, sowie die Entwicklung neuartiger Sensoren für die Erdbeobachtung zu initiieren. Insbesondere schaffen Messungen mit Atominterferometern im Weltraum den Rahmen für Tests der allgemeinen Relativitätstheorie, der Suche nach dunkler Energie, satellitengestützter Erdbeobachtung und der Detektion von Gravitationswellen in einem auf der Erde nicht erreichbaren Regime. Die technischen Ansprüche einer Weltraummission unterscheiden sich grundlegend von denen eines Laboraufbaus. Neben einer Optimierung bezüglich der Masse, der Leistungsaufnahme und des Volumens muss die Apparatur autonom und wartungsfrei arbeiten, sowie robust gegen Vibrationen und Beschleunigungen während des Aufstiegs und Wiedereintritts in die Atmosphäre sein. Mit der MAIUS-1 Mission ist es am 23.01.2017 zum ersten Mal gelungen Bose- Einstein-Kondensate im Weltraum zu erzeugen. Erstmals wurde eine solche Apparatur an Bord einer Höhenforschungsrakete betrieben und hat Schlüsselmethoden für präzise Materiewelleninterferometrie demonstriert. In den insgesamt 13 Minuten des Parabelfluges befand sich die Nutzlast sechs Minuten lang über bei einer Höhe von 100km unter Mikrogravitationsbedingungen. Während des Starts und Aufstiegs konnten für eine Minute Experimente zum Kühlen und Fangen kalter atomarer Ensembles in dieser hochdynamischen Umgebung durchgeführt werden. In der Mikrogravitationsphase wurde der Phasenübergang zum Bose-Einstein- Kondensat mit mehr als 105 Rubidiumatomen untersucht. Die Präparation der ultrakalten Ensembles für die Interferometrie wurde charakterisiert und autonom vom System optimiert, wobei sich die Reproduzierbarkeit aller Prozesse zur Kühlung zeigte. Des Weiteren wurden Zwei-Photonen-Prozesse genutzt, um die Materiewelle in die Superposition von Impulszuständen zu überführen und zur Interferenz zu bringen. Somit konnte die Kohärenz über die gesamte Ausdehnung der Kondensate nachgewiesen werden. Mit jeder Licht-Materie-Wechselwirkung wurde eine zusätzliche Phasenmodulation auf die Materiewelle aufgeprägt. Diese Struktur wurde nach einer freien Evolutionszeit in der räumlichen Dichteverteilung sichtbar und konnte für weitere Analysen verschiedener Spinorkomponenten des Ensembles verwendet werden. Die Erkenntnisse zur Präparation der ultrakalten Ensembles und zur Interferometrie im Weltraum wie auch die entwickelten Technologien ermöglichen künftige Missionen.DLR/QUANTUS/50WP1431/E

Microgravity facilities for cold atom experiments

Microgravity platforms enable cold atom research beyond experiments in typical laboratories by removing restrictions due to the gravitational acceleration or compensation techniques. While research in space allows for undisturbed experimentation, technological readiness, availability and accessibility present challenges for experimental operation. In this work we focus on the main capabilities and unique features of ground-based microgravity facilities for cold atom research. A selection of current and future scientific opportunities and their high demands on the microgravity environment are presented, and some relevant ground-based facilities are discussed and compared. Specifically, we point out the applicable free fall times, repetition rates, stability and payload capabilities, as well as programmatic and operational aspects of these facilities. These are contrasted with the requirements of various cold atom experiments. Besides being an accelerator for technology development, ground-based microgravity facilities allow fundamental and applied research with the additional benefit of enabling hands-on access to the experiment for modifications and adjustments

A Dual-Species Atom Interferometer Payload for Operation on Sounding Rockets

We report on the design and the construction of a sounding rocket payload capable of performing atom interferometry with Bose-Einstein condensates of 41 K and 87 Rb. The apparatus is designed to be launched in two consecutive missions with a VSB-30 sounding rocket and is qualified to withstand the expected vibrational loads of 1.8 g root-mean-square in a frequency range between 20–2000 Hz and the expected static loads during ascent and re-entry of 25 g. We present a modular design of the scientific payload comprising a physics package, a laser system, an electronics system and a battery module. A dedicated on-board software provides a largely automated process of predefined experiments. To operate the payload safely in laboratory and flight mode, a thermal control system and ground support equipment has been implemented and will be presented. The payload presented here represents a cornerstone for future applications of matter wave interferometry with ultracold atoms on satellites

Ultracold atom interferometry in space

Bose-Einstein condensates (BECs) in free fall constitute a promising source for space-borne interferometry. Indeed, BECs enjoy a slowly expanding wave function, display a large spatial coherence and can be engineered and probed by optical techniques. Here we explore matter-wave fringes of multiple spinor components of a BEC released in free fall employing light-pulses to drive Bragg processes and induce phase imprinting on a sounding rocket. The prevailing microgravity played a crucial role in the observation of these interferences which not only reveal the spatial coherence of the condensates but also allow us to measure differential forces. Our work marks the beginning of matter-wave interferometry in space with future applications in fundamental physics, navigation and earth observation

Technology roadmap for cold-atoms based quantum inertial sensor in space

Recent developments in quantum technology have resulted in a new generation of sensors for measuring inertial quantities, such as acceleration and rotation. These sensors can exhibit unprecedented sensitivity and accuracy when operated in space, where the free-fall interrogation time can be extended at will and where the environment noise is minimal. European laboratories have played a leading role in this field by developing concepts and tools to operate these quantum sensors in relevant environment, such as parabolic flights, free-fall towers, or sounding rockets. With the recent achievement of Bose-Einstein condensation on the International Space Station, the challenge is now to reach a technology readiness level sufficiently high at both component and system levels to provide "off the shelf"payload for future generations of space missions in geodesy or fundamental physics. In this roadmap, we provide an extensive review on the status of all common parts, needs, and subsystems for the application of atom-based interferometers in space, in order to push for the development of generic technology components

Space-borne Bose-Einstein condensation for precision interferometry

Space offers virtually unlimited free-fall in gravity. Bose-Einstein condensation (BEC) enables ineffable low kinetic energies corresponding to pico- or even femtokelvins. The combination of both features makes atom interferometers with unprecedented sensitivity for inertial forces possible and opens a new era for quantum gas experiments. On January 23, 2017, we created Bose-Einstein condensates in space on the sounding rocket mission MAIUS-1 and conducted 110 experiments central to matter-wave interferometry. In particular, we have explored laser cooling and trapping in the presence of large accelerations as experienced during launch, and have studied the evolution, manipulation and interferometry employing Bragg scattering of BECs during the six-minute space flight. In this letter, we focus on the phase transition and the collective dynamics of BECs, whose impact is magnified by the extended free-fall time. Our experiments demonstrate a high reproducibility of the manipulation of BECs on the atom chip reflecting the exquisite control features and the robustness of our experiment. These properties are crucial to novel protocols for creating quantum matter with designed collective excitations at the lowest kinetic energy scales close to femtokelvins.Comment: 6 pages, 4 figure

Technology roadmap for cold-atoms based quantum inertial sensor in space

Recent developments in quantum technology have resulted in a new generation of sensors for measuring inertial quantities, such as acceleration and rotation. These sensors can exhibit unprecedented sensitivity and accuracy when operated in space, where the free-fall interrogation time can be extended at will and where the environment noise is minimal. European laboratories have played a leading role in this field by developing concepts and tools to operate these quantum sensors in relevant environment, such as parabolic flights, free-fall towers, or sounding rockets. With the recent achievement of Bose–Einstein condensation on the International Space Station, the challenge is now to reach a technology readiness level sufficiently high at both component and system levels to provide “off the shelf” payload for future generations of space missions in geodesy or fundamental physics. In this roadmap, we provide an extensive review on the status of all common parts, needs, and subsystems for the application of atom-based interferometers in space, in order to push for the development of generic technology components

Technologies and Concepts of the UHV System for the MAIUS-2/3 Sounding Rocket Missions

During the two sounding rocket missions MAIUS-2 and MAIUS-3, it is planned to perform sequential and simultaneous dualspecies atom interferometry with Bose-Einstein condensates of Potassium-41 and Rubidium-87. The scientific payload of the MAIUS missions will be launched on-board a VSB-30 sounding rocket launched from Esrange in Sweden. The flights of these rockets allows for approximately 360 s of microgravity conditions. The microgravity environment offers experiments on timescales that are not possible on ground based experiments. To perform long lifetimes of the BEC, a pressure <= 5·10^(-10) mbar needs to be reached and maintained in the vacuum chamber. During ascent of the rocket, vibrational loads of 1.8 g RMS in the frequency range of 20-2000 Hz and accelerations of up to 13 g are applied to the vacuum system and the payload. During re-entry and landing static loads can reach a level of up to 50 g. The ultra-high vacuum system presented in this talk is designed to withstand these loads while maintaining the vacuum quality. Therefore, the sealing technologies and pumping concepts which are used under this challenging requirements, needed to be tested and qualified. This talk presents the ultra-high vacuum system of the MAIUS-2/3 payload in detail, as well as its vibration and qualification tests at the shaker test facility at the Center of Applied Space Technology and Microgravity (ZARM) in Bremen