Experiments with ultracold quantum gases are a rapidly advancing research field with many applications in fundamental physics and quantum technology. Here, we report on a high-flux generation of Bose-Einstein condensate mixtures of 41K and 87Rb, using a fully integrated sounding rocket setup. We compare the release and the free expansion of the quantum mixtures obtained with the apparatus placed on ground or in free fall in an Einstein-Elevator. The release dynamics are governed by the intra- and interspecies interactions as well as the decaying magnetic field during the release. The latter can be minimized by a dedicated switch-off protocol of the trap generating currents where an exact model enabled us to characterize the interaction effects. Our results establish a new benchmark for generating ultracold mixtures on mobile platforms, with direct relevance for future experiments on interacting quantum gases and tests of the equivalence principle in space.

The DESIRE project aims to test chameleon field theories as potential candidates for dark energy. The chameleon field is a light scalar field that is subject to screening mechanisms in dense environments making them hardly detectable. The project is designed to overcome this challenge. To this end, a specially designed source mass generates periodic gravitational and chameleon potentials. The design of the source mass allows for adjustment of the amplitude and periodicity of the gravitational potential while keeping the chameleon potential unchanged. The periodicity of the potentials makes them distinguishable from the environment and allows for resonant detection using multiloop atom interferometry under microgravity conditions.

This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more km-scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions.

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.

We report on the design and the construction of a sounding rocket payload capable of performing atom interferometry with Bose-Einstein condensates of 41K and 87Rb. 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.

A strong potential gain for space applications is expected from the anticipated performances of inertial sensors based on cold atom interferometry (CAI) that measure the acceleration of freely falling independent atoms by manipulating them with laser light.In this context, CNES and its partners initiated a phase 0 study, called CARIOQA, in order to develop a Quantum Pathfinder Mission unlocking key features of atom interferometry for space and paving the way for future ambitious space missions utilizing this technology.As a cornerstone for the implementation of quantum sensors in space, the CARIOQA phase 0 aimed at defining the Quantum Pathfinder Mission's scenario and associated performance objectives.To comply with these objectives, the payload architecture has been designed to achieve long interrogation time and active rotation compensation on a BEC-based atom interferometer.A study of the satellite architecture, including all the subsystems, has been conducted.Several technical solutions for propulsion and attitude control have been investigated in order to guarantee optimal operating conditions (limitation of micro-vibrations, maximization of measurement time).A preliminary design of the satellite platform was performed.

Dark energy constitutes ~70% of the universe, which explains the observed accelerated expansion of the universe. While little is known about the nature of dark energy, it is conjectured that it is a new scalar field that interacts normal matter at the cosmological scale. Recently, cold atom experiments in laboratory have contributed significantly on the constraints of chameleon and symmetron parameters. These experiments are currently limited by the knowledge of the Newtonian gravity of the test masses, and eventually by the uncertainty of the gravitational constant G. In this talk, we will present a joint project between JPL and Leibniz University Hannover, in which atom interferometers will be implemented in the 4-second microgravity environment in the Einstein-Elevator facility at Hannover, Germany. We will illustrate the measurement concept for constraining dark energy models, and report the progress of the joint effort.

Development of space proven technologies, fundamental research in microgravity and preparation of future space missions all benefit from next generation drop tower facilities like the Einstein-Elevator. The facility is being made available within a DFG core facility center in Hannover.

We present a highly efficient method for the numerical solution of coupled Gross–Pitaevskii equations describing the evolution dynamics of a multi-species mixture of Bose–Einstein condensates in time-dependent potentials. This method, based on a moving and expanding reference frame, compares favorably to a more standard but much more computationally expensive solution based on a frozen frame. It allows an accurate description of the long-time behavior of interacting, multi-species quantum mixtures including the challenging problem of long free expansions relevant to microgravity and space experiments. We demonstrate a successful comparison to experimental measurements of a binary Rb–K mixture recently performed with the payload of a sounding rocket experiment.

The 53rd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics will take place from May 30 – June 3, 2022 in Orlando, Fl, USA. Virtual Presenter Help Desk

We exploit red- and blue-detuned magneto-optical trapping (MOT) of 87Rb benefitting from a simplified setup and a novel approach based on liquid crystal variable retarders (LCVR). To maintain the trapping forces when switching from a red- to a blue-detuned MOT, the handedness of the circular polarization of the cooling beams needs to be reversed. LCVRs allow fast polarization control and represent compact, simple, and cost-efficient components, which can easily be implemented in existing laser systems. This way, we achieve a blue-detuned type-II MOT for 8.7 × 108 atoms of 87Rb with sub-Doppler temperatures of 44 μK well below the temperatures reached in a conventional 87Rb type-I MOT. The phase space density is increased by more than two orders of magnitude compared to the standard red-detuned type-I MOT. The setup can readily be transferred to any other systems working with 87Rb.

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.

In January 2017 a first sounding rocket mission housing experiments on matter-wave interferometry, MAIUS-1 (Materiewellen-Interferometrie unter Schwerelosigkeit Matter-Wave Interferometry under Microgravity), has been launched. Following this campaign, two sounding rocket missions, MAIUS-2 and MAIUS-3, are planned to perform sequential and simultaneous dual-species atom interferometry with Bose-Einstein condensates (BEC) 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 ights of these rockets allows for approximately 360 s of microgravity conditions. It therefore overs a microgravity environment for experiments on timescales not accessible in ground based experiments, such as in the drop tower. During ascent of the rocket, vibrational loads of up to 1.8 g RMS in the frequency range of 20- 2000 Hz and accelerations of up to 13 g can occur. Furthermore, static loads, caused by the re-entry and the landing, can be as high as 50 g. Both missions MAIUS-2 and MAIUS-3 y the same payload, called MAIUS-B. Consequently, the payload needs to be designed to withstand the aforementioned loads

The new design and optimization became necessary as the MAIUS-2/3 experiment requires more components in the laser system and (laser-) electronics to realize cooling and interferometry for both species and mixtures. Without a design improvement, the additional components would result in a mass and length of the payload exceeding the weight and length limits for a stable re-entry. Moreover an increase in mass results in a reduction of the available microgravity time for experiments. Therefore, the laser system, laser electronics, electronics, and physics package had to be optimized and redesigned.