Quantum gas mixtures and dual-species atom interferometry in space

• Published in: Nature (London) 2023-11, Vol.623 (7987), p.502-508
• Main Authors: Elliott, Ethan R., Aveline, David C., Bigelow, Nicholas P., Boegel, Patrick, Botsi, Sofia, Charron, Eric, D’Incao, José P., Engels, Peter, Estrampes, Timothé, Gaaloul, Naceur, Kellogg, James R., Kohel, James M., Lay, Norman E., Lundblad, Nathan, Meister, Matthias, Mossman, Maren E., Müller, Gabriel, Müller, Holger, Oudrhiri, Kamal, Phillips, Leah E., Pichery, Annie, Rasel, Ernst M., Sackett, Charles A., Sbroscia, Matteo, Schleich, Wolfgang P., Thompson, Robert J., Williams, Jason R.
• Format: Article
• Language: English
• Subjects: 639/766/36/1125; 639/766/483; Atom interferometry; Bose-Einstein condensates; Cold; Cold atoms; Condensed Matter; Cooling; Free fall; Gas mixtures; Gravitation theory; Gravity; Gravity theories; Humanities and Social Sciences; Interferometry; International Space Station; Isotopes; Lasers; multidisciplinary; Optics; Physics; Potassium; Quantum chemistry; Quantum Gases; Quantum phenomena; Quantum sensors; Science; Science (multidisciplinary); Space stations; Strong interactions (field theory); Superfluidity; Temperature effects; Upgrading
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-023-06645-w

The capability to reach ultracold atomic temperatures in compact instruments has recently been extended into space 1 , 2 . Ultracold temperatures amplify quantum effects, whereas free fall allows further cooling and longer interactions time with gravity—the final force without a quantum description. On Earth, these devices have produced macroscopic quantum phenomena such as Bose–Einstein condensates (BECs), superfluidity, and strongly interacting quantum gases 3 . Terrestrial quantum sensors interfering the superposition of two ultracold atomic isotopes have tested the universality of free fall (UFF), a core tenet of Einstein’s classical gravitational theory, at the 10 −12 level 4 . In space, cooling the elements needed to explore the rich physics of strong interactions or perform quantum tests of the UFF has remained elusive. Here, using upgraded hardware of the multiuser Cold Atom Lab (CAL) instrument aboard the International Space Station (ISS), we report, to our knowledge, the first simultaneous production of a dual-species BEC in space (formed from 87 Rb and 41 K), observation of interspecies interactions, as well as the production of 39 K ultracold gases. Operating a single laser at a ‘magic wavelength’ at which Rabi rates of simultaneously applied Bragg pulses are equal, we have further achieved the first spaceborne demonstration of simultaneous atom interferometry with two atomic species ( 87 Rb and 41 K). These results are an important step towards quantum tests of UFF in space and will allow scientists to investigate aspects of few-body physics, quantum chemistry and fundamental physics in new regimes without the perturbing asymmetry of gravity. Using upgraded hardware of the multiuser Cold Atom Lab (CAL) aboard the International Space Station (ISS), Bose–Einstein condensates (BECs) of two atomic isotopes are simultaneously created and used to demonstrate interspecies interactions and dual species atom interferometry in space.