Attosecond chronoscopy of electron wave-packets probing entanglement and time-ordering of quantum processes

Knut and Alice Wallenberg project from the University of Gothenburg :

If an atom, molecule or surface absorbs a photon of sufficiently high energy, an electron may be ejected. This ‘photoelectric’ effect marked the foundation of quantum mechanics and has been tacitly regarded as instantaneous until very recently, when newly available attosecond light pulses enabled measuring real delays in the physical process. The development of such attosecond-precise time measurements offers the opportunity for a revolution in atomic physics as interpreted by quantum mechanics, where the issue of time as an observable is a longstanding problem. The overall aim of this project is testing the quantum mechanical description of time-dependent phenomena. This will be done by characterizing both in phase and amplitude electron wave-packets primarily ejected from negative ions to answer fundamental questions such as:
•Where, how and when do photoelectrons leave a system upon photoabsorption?
•Do real decay processes depart from the widely assumed exponential law?
•If several electrons are emitted, how are the individual ejections time-ordered?
•How does the property of entanglement evolve in time?
To answer these specific questions, we have gathered a team of internationally recognized experts in the key areas of multi-particle correlation spectroscopy, attosecond pulse creation and control, time-dependent many-body theory and the production of negative ions. The project is possible only because we uniquely combine these areas of expertise and can capitalize on the latest technological developments, for several of which we have ourselves been major pioneers. The results are envisioned as world leading contributions, both to the specific field of atomic and molecular physics, and to natural science in general. There is tremendous interest in such studies for their relevance to intense radiation environments like the Earth’s atmosphere and interstellar space, to plasmas and chemical reactions as well as to the development of e.g. quantum computers.