Li, SiqiDriver, TaranRosenberger, PhilippChampenois, Elio G.Duris, JosephAl-Haddad, AndreAverbukh, VitaliBarnard, Jonathan C. T.Berrah, NoraBostedt, ChristophBucksbaum, Philip H.Coffee, Ryan N.DiMauro, Louis F.Fang, LiGarratt, DouglasGatton, AverellGuo, ZhaohengHartmann, GregorHaxton, DanielHelml, WolframHuang, ZhirongLaForge, Aaron C.Kamalov, AndreiKnurr, JonasLin, Ming-FuLutman, Alberto A.MacArthur, James P.Marangos, Jon P.Nantel, MeganNatan, AdiObaid, RazibO'Neal, Jordan T.Shivaram, Niranjan H.Schori, AviadWalter, PeterLi Wang, AnnaWolf, Thomas J. A.Zhang, ZhenKling, Matthias F.Marinelli, AgostinoCryan, James P.2022-02-282022-02-282022-02-282022-01-2110.1126/science.abj2096https://infoscience.epfl.ch/handle/20.500.14299/185896WOS:000745036100027In quantum systems, coherent superpositions of electronic states evolve on ultrafast time scales (few femtoseconds to attoseconds; 1 attosecond = 0.001 femtoseconds = 10(-18) seconds), leading to a time-dependent charge density. Here we performed time-resolved measurements using attosecond soft x-ray pulses produced by a free-electron laser, to track the evolution of a coherent core-hole excitation in nitric oxide. Using an additional circularly polarized infrared laser pulse, we created a clock to time-resolve the electron dynamics and demonstrated control of the coherent electron motion by tuning the photon energy of the x-ray pulse. Core-excited states offer a fundamental test bed for studying coherent electron dynamics in highly excited and strongly correlated matter.Multidisciplinary SciencesScience & Technology - Other Topicsreal-time observationcharge migrationo 1sexcitationdynamicsspectratext::journal::journal article::research article