I-11

Direct observation of ultrafast quantum many-body dynamics in a strongly-correlated ultracold Rydberg gas

N. Takei^1,2,3,9, C. Sommer^1,2,3,9, C. Genes^3,4, G. Pupillo^3,5, H. Goto¹, K. Koyasu^1,2,3, H. Chiba^1,3,6, M. Weidemüller^3,7,8, K. Ohmori^1,2,3,9*

¹Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki 444-8585, Japan

²SOKENDAI (The Graduate University for Advanced Studies), Okazaki 444-8585, Japan

³CREST, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan

⁴Institut für Theoretische Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria

⁵IPCMS (UMR 7504) and ISIS (UMR 7006), University of Strasbourg and CNRS, 67000 Strasbourg, France

⁶Faculty of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551, Japan

⁷Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg, Germany

⁸Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, and CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China

⁹These authors contributed equally to this work.

Many-body correlations govern a variety of important quantum phenomena such as the emergence of magnetism and superconductivity in condensed matter. Understanding quantum many-body systems is thus one of the holy grails of modern sciences. Here we demonstrate a new pathway to it; a strongly-correlated ultracold Rydberg gas is created with a broadband picosecond laser pulse, and its ultrafast many-body electron dynamics is directly observed by time-domain Ramsey interferometry with attosecond precision. Our new approach will offer a versatile platform to observe and manipulate nonequilibrium dynamics of strongly-correlated quantum many-body systems on the ultrafast timescale.