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

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 87Rb, 39K, and 41K, 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 87Rb with microwave-based evaporation and the generation of ultracold dual-species quantum gas mixtures of 39K/87Rb and 41K/87Rb in an atom chip trap via sympathetic cooling.

Atomic source selection in space-borne gravitational wave detection

“…While further experimental development is necessary to meet the atomic flux requirements of 4×10 7 atoms s −1 , recent robust BEC production in microgravity [81] and space [82] demonstrate important steps towards meeting this goal. In general, the exploration of cold atom technologies in microgravity [23,83,84] and in space [85,86] is a promising and rapidly progressing field of research.…”

The space atom laser: an isotropic source for ultra-cold atoms in microgravity

“…The setup of our model sequence is based on realistic values that are in accordance with the planned capabilities of the CAL apparatus [37]. Table 1 contains the values of the relevant physical quantities, which correspond to only one of the many different scenarios that we have been testing for our study.…”

“…This behavior is not surprising since the chemical potential of the initial BEC measured in magnetic-field strength is given by 2 0 . 4 5m G 1 B m m = -according to equations (15) and (37). Thus, deviations of the magnetic field of this order shift the resonance position of the rf transition faraway enough from where the atoms actually are to suppress any outcoupling.…”

Topological spinor vortex matter on spherical surface induced by non-Abelian spin-orbital-angular-momentum coupling

“…However, in traditional schemes, the creation of hollow spherical surface magnetic trap is challenging on Earth due to the presence of gravitational sag. To overcome this, micro-gravity conditions are usually expected which can only be satisfied in the space-based Cold Atomic Laboratory [64,65]. This greatly increases the costs and difficulties for experimentally exploring many novel physics in such curved geometry.…”