Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Chinese Journal of Space Science

Research on Ultracold Atom Physics in Microgravity

Lin LI, Bin Wang, Xiaoji Zhou, Xuzong Chen, Tang Li, Liang Liu

Published Jan 1, 2025• 0 citations
Publisher

Abstract

The China Space Station (CSS) provides an ideal experimental platform for researching and applying ultracold atoms in microgravity. On 31 October 2022, the Cold Atom Physics Research Rack (CAPR) was launched to the CSS together with the Mengtian lab module, designed by the Shanghai Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences (SIOM) and Peking University. The main goal of the CAPR is to build an ultracold atomic physics experiment platform using 87Rb Bose Einstein Condensate (BEC) in the CSS. In microgravity, ultracold atoms can be cooled to picokelvin (pK) via Two-Stage Crossed Beams Cooling (TSCBC), which is three orders of magnitude lower than on earth and can inspire the novel physical phenomena. The preparation of the BEC and the deep cooling are introduced in this paper, as well as a series of advancements in ultracold atoms in microgravity. The CAPR is an experimental platform that relies on evaporative cooling in a crossed optical dipole trap. Furthermore, the CAPR’s design scheme and ground verification experiment are also introduced. So far, the CAPR has continued to conduct research on ultracold atoms in microgravity, with more than two years of uninterrupted operation in orbit. Up to now, preliminary experimental results have been achieved, realizing the primary purpose of the CAPR.

DOI
10.11728/cjss2025.01.2024-0174

Related papers

Deep cooling scheme of quantum degenerate gas and ground experimental verification for chinese space station

Hui Li, Jiachen Yu, Xiaolong Yuan +15 more

The Cold Atom Physics Rack (CAPR) of Chinese space station will be launched at the end of 2022. The important goal of CAPR is to achieve BEC at 100 pk. In order to obtain ultracold atoms in microgravity of space station, we propose a two-stage cooling scheme using all-optical trap with different waist beams. The cold atom cloud obtained by this scheme is composed of condensate and thermal atoms around condensate. The design of our two-stage cooling scheme will effectively reduce the temperature of the thermal atom cloud and the effective temperature generated by the interaction energy of the condensate. The atomic temperature of 5 nk is obtained from the ground test experiment, and the corresponding temperature under the microgravity condition of the space station is theoretically predicted to be less than 100 pk. Taking the advantages of ultracold temperature and long-time detection, many scientific experiments will be arranged. In this paper, the ground test experiments based on ground principle prototype and pre-prototype for CAPR are also introduced.

Frontiers in Physics•Sep 7, 2022•4 citations

The Design, Realization, and Validation of the Scheme for Quantum Degenerate Research in Microgravity

Lin Li, Wei Xiong, Bin Wang +20 more

In microgravity, atoms can be prepared to a lower temperature and manipulated with a longer time. The Cold Atom Physics Research Rack (CAPR) in Chinese Space Station, which aims to prepare quantum degenerate gas for deep cooling and quantum simulation in microgravity, has been designed, realized, and validated. We built an integrated CAPR, consisting of a physical system, an all-fiber 780nm laser system and a low phase noise 1064nm fiber laser system, and an electrical driving and controlling system. With the CAPR, a87Rb quantum degenerate gas with 1.2ⅹ105atoms and a temperature below 30nK was achieved on ground. In this article, we also show the robustness of the rack, based on the experimental results before and after the simulation of the vibration and impact during the launch.

IEEE photonics journal•Apr 10, 2023•8 citations

Momentum filtering scheme of cooling atomic clouds for the Chinese Space Station

Hui Li, Biao Wu, Jiachen Yu +6 more

To obtain cold atom samples with temperatures lower than 100 pK in the cold atom physics rack experiment of the Chinese Space Station, we propose to use the momentum filtering method for deep cooling of atoms.This paper introduces the experimental results of the momentum filtering method verified by our ground testing system.In the experiment, we designed a specific experimental sequence of standing-wave light pulses to control the temperature, atomic number, and size of the atomic cloud.The results show that the momentum filter can effectively and conveniently reduce the temperature of the atomic cloud and the energy of Bose-Einstein condensation, and can be flexibly combined with other cooling methods to enhance the cooling effect.This work provides a method for the atomic cooling scheme of the ultra-cold atomic system on the ground and on the space station, and shows a way of deep cooling atoms.

Chinese Optics Letters•Jan 1, 2023•4 citations

All-fiber laser system for all-optical 87Rb Bose Einstein condensate to space application

Lin Li, Cuiyun Zhou, Wei Xiong +16 more

In the development of the Cold Atom Physics Research Rack (CAPR) on board the Chinese Space Station, the laser system plays a critical role in preparing the all-optical 87Rb Bose–Einstein condensates (BECs). An all-fiber laser system has been developed for CAPR to provide the required optical fields for atom interaction and to maintain the beam pointing in long-term operation. The laser system integrates a 780 nm fiber laser system and an all-fiber optical control module for sub-Doppler cooling, as well as an all-fiber 1064 nm laser system for evaporative cooling. The high-power, single-frequency 780 nm lasers are achieved through rare-Earth doped fiber amplification, fiber frequency-doubling, and frequency stabilization technology. The all-fiber optical control module divides the output of the 780 nm laser system into 15 channels and regulates them for cooling, trapping, and probing atoms. Moreover, the power consistency of each pair of cooling beams is ensured by three power tracking modules, which is a prerequisite for maintaining stable MOT and molasses. A high-power, compact, controlled-flexible, and highly stable l064 nm all-fiber laser system employing two-stage ytterbium-doped fiber amplifier (YDFA) technology has been designed for evaporative cooling in the optical dipole trap (ODT). Finally, an all-optical 87Rb BEC is realized with this all-fiber laser system, which provides an alternative solution for trapping and manipulating ultra-cold atoms in challenging environmental conditions.

Applied Optics•Sep 25, 2023•7 citations

The Bose-Einstein Condensate and Cold Atom Laboratory

Kai Frye, Sven Abend, Wolfgang Bartosch +51 more

Abstract Microgravity eases several constraints limiting experiments with ultracold and condensed atoms on ground. It enables extended times of flight without suspension and eliminates the gravitational sag for trapped atoms. These advantages motivated numerous initiatives to adapt and operate experimental setups on microgravity platforms. We describe the design of the payload, motivations for design choices, and capabilities of the Bose-Einstein Condensate and Cold Atom Laboratory (BECCAL), a NASA-DLR collaboration. BECCAL builds on the heritage of previous devices operated in microgravity, features rubidium and potassium, multiple options for magnetic and optical trapping, different methods for coherent manipulation, and will offer new perspectives for experiments on quantum optics, atom optics, and atom interferometry in the unique microgravity environment on board the International Space Station.

arXiv:1912.04849•EPJ Quantum Technology•Jan 4, 2021•148 citations

NASA’s Cold Atom Lab (CAL): system development and ground test status

Ethan Elliott, Markus Krutzik, Jason Williams +2 more

Abstract We report the status of the Cold Atom Lab (CAL) instrument to be operated aboard the International Space Station (ISS). Utilizing a compact atom chip-based system to create ultracold mixtures and degenerate samples of 87 Rb, 39 K, and 41 K, CAL is a multi-user facility developed by NASA’s Jet Propulsion Laboratory to provide the first persistent quantum gas platform in the microgravity conditions of space. Within this unique environment, atom traps can be decompressed to arbitrarily weak confining potentials, producing a new regime of picokelvin temperatures and ultra-low densities. Further, the complete removal of these confining potential allows the free fall evolution of ultracold clouds to be observed on unprecedented timescales compared to earthbound instruments. This unique facility will enable novel ultracold atom research to be remotely performed by an international group of principle investigators with broad applications in fundamental physics and inertial sensing. Here, we describe the development and validation of critical CAL technologies, including demonstration of the first on-chip Bose–Einstein condensation (BEC) of 87 Rb with microwave-based evaporation and the generation of ultracold dual-species quantum gas mixtures of 39 K/ 87 Rb and 41 K/ 87 Rb in an atom chip trap via sympathetic cooling.

npj Microgravity•Jul 20, 2018•165 citations
The China Space Station (CSS) provides an ideal experimental platform for researching and applying ultracold atoms in microgravity. On 31 October 2022, the Cold Atom Physics Research Rack (CAPR) was launched to the CSS together with the Mengtian lab module, designed by the Shanghai Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences (SIOM) and Peking University. The main goal of the CAPR is to build an ultracold atomic physics experiment platform using 87Rb Bose Einstein Condensate (BEC) in the CSS. In microgravity, ultracold atoms can be cooled to picokelvin (pK) via Two-Stage Crossed Beams Cooling (TSCBC), which is three orders of magnitude lower than on earth and can inspire the novel physical phenomena. The preparation of the BEC and the deep cooling are introduced in this paper, as well as a series of advancements in ultracold atoms in microgravity. The CAPR is an experimental platform that relies on evaporative cooling in a crossed optical dipole trap. Furthermore, the CAPR’s design scheme and ground verification experiment are also introduced. So far, the CAPR has continued to conduct research on ultracold atoms in microgravity, with more than two years of uninterrupted operation in orbit. Up to now, preliminary experimental results have been achieved, realizing the primary purpose of the CAPR.
The Cold Atom Physics Rack (CAPR) of Chinese space station will be launched at the end of 2022. The important goal of CAPR is to achieve BEC at 100 pk. In order to obtain ultracold atoms in microgravity of space station, we propose a two-stage cooling scheme using all-optical trap with different waist beams. The cold atom cloud obtained by this scheme is composed of condensate and thermal atoms around condensate. The design of our two-stage cooling scheme will effectively reduce the temperature of the thermal atom cloud and the effective temperature generated by the interaction energy of the condensate. The atomic temperature of 5 nk is obtained from the ground test experiment, and the corresponding temperature under the microgravity condition of the space station is theoretically predicted to be less than 100 pk. Taking the advantages of ultracold temperature and long-time detection, many scientific experiments will be arranged. In this paper, the ground test experiments based on ground principle prototype and pre-prototype for CAPR are also introduced.
In microgravity, atoms can be prepared to a lower temperature and manipulated with a longer time. The Cold Atom Physics Research Rack (CAPR) in Chinese Space Station, which aims to prepare quantum degenerate gas for deep cooling and quantum simulation in microgravity, has been designed, realized, and validated. We built an integrated CAPR, consisting of a physical system, an all-fiber 780nm laser system and a low phase noise 1064nm fiber laser system, and an electrical driving and controlling system. With the CAPR, a87Rb quantum degenerate gas with 1.2ⅹ105atoms and a temperature below 30nK was achieved on ground. In this article, we also show the robustness of the rack, based on the experimental results before and after the simulation of the vibration and impact during the launch.
To obtain cold atom samples with temperatures lower than 100 pK in the cold atom physics rack experiment of the Chinese Space Station, we propose to use the momentum filtering method for deep cooling of atoms.This paper introduces the experimental results of the momentum filtering method verified by our ground testing system.In the experiment, we designed a specific experimental sequence of standing-wave light pulses to control the temperature, atomic number, and size of the atomic cloud.The results show that the momentum filter can effectively and conveniently reduce the temperature of the atomic cloud and the energy of Bose-Einstein condensation, and can be flexibly combined with other cooling methods to enhance the cooling effect.This work provides a method for the atomic cooling scheme of the ultra-cold atomic system on the ground and on the space station, and shows a way of deep cooling atoms.
In the development of the Cold Atom Physics Research Rack (CAPR) on board the Chinese Space Station, the laser system plays a critical role in preparing the all-optical 87Rb Bose–Einstein condensates (BECs). An all-fiber laser system has been developed for CAPR to provide the required optical fields for atom interaction and to maintain the beam pointing in long-term operation. The laser system integrates a 780 nm fiber laser system and an all-fiber optical control module for sub-Doppler cooling, as well as an all-fiber 1064 nm laser system for evaporative cooling. The high-power, single-frequency 780 nm lasers are achieved through rare-Earth doped fiber amplification, fiber frequency-doubling, and frequency stabilization technology. The all-fiber optical control module divides the output of the 780 nm laser system into 15 channels and regulates them for cooling, trapping, and probing atoms. Moreover, the power consistency of each pair of cooling beams is ensured by three power tracking modules, which is a prerequisite for maintaining stable MOT and molasses. A high-power, compact, controlled-flexible, and highly stable l064 nm all-fiber laser system employing two-stage ytterbium-doped fiber amplifier (YDFA) technology has been designed for evaporative cooling in the optical dipole trap (ODT). Finally, an all-optical 87Rb BEC is realized with this all-fiber laser system, which provides an alternative solution for trapping and manipulating ultra-cold atoms in challenging environmental conditions.
Abstract Microgravity eases several constraints limiting experiments with ultracold and condensed atoms on ground. It enables extended times of flight without suspension and eliminates the gravitational sag for trapped atoms. These advantages motivated numerous initiatives to adapt and operate experimental setups on microgravity platforms. We describe the design of the payload, motivations for design choices, and capabilities of the Bose-Einstein Condensate and Cold Atom Laboratory (BECCAL), a NASA-DLR collaboration. BECCAL builds on the heritage of previous devices operated in microgravity, features rubidium and potassium, multiple options for magnetic and optical trapping, different methods for coherent manipulation, and will offer new perspectives for experiments on quantum optics, atom optics, and atom interferometry in the unique microgravity environment on board the International Space Station.
Abstract We report the status of the Cold Atom Lab (CAL) instrument to be operated aboard the International Space Station (ISS). Utilizing a compact atom chip-based system to create ultracold mixtures and degenerate samples of 87 Rb, 39 K, and 41 K, CAL is a multi-user facility developed by NASA’s Jet Propulsion Laboratory to provide the first persistent quantum gas platform in the microgravity conditions of space. Within this unique environment, atom traps can be decompressed to arbitrarily weak confining potentials, producing a new regime of picokelvin temperatures and ultra-low densities. Further, the complete removal of these confining potential allows the free fall evolution of ultracold clouds to be observed on unprecedented timescales compared to earthbound instruments. This unique facility will enable novel ultracold atom research to be remotely performed by an international group of principle investigators with broad applications in fundamental physics and inertial sensing. Here, we describe the development and validation of critical CAL technologies, including demonstration of the first on-chip Bose–Einstein condensation (BEC) of 87 Rb with microwave-based evaporation and the generation of ultracold dual-species quantum gas mixtures of 39 K/ 87 Rb and 41 K/ 87 Rb in an atom chip trap via sympathetic cooling.