Physical Society Colloquium
Attosecond Ionization Dynamics and Time Delays
Physics Department ETH Z�rich
The basic motivation is to understand and ultimately control how matter
functions at the electronic, atomic and molecular level. Initially our focus is
on the question how quanta of energy and charge are transported on an atomic
spatial and attosecond time scale. In principle, time dependent-processes
in quantum mechanics are described by the time-dependent Schrödinger
Equation (TDSE). The challenge is that the TDSE in most cases cannot be
solved without approximations and that time is not an operator and therefore
not a direct observable. Semi-classical models, on the other hand, seem to
explain suprisingly well many current attosecond measurements. Attosecond
measurements have advanced rapidly with reproducable and high-quality data,
allowing for very fundamental tests for our current understanding and models
in time-dependent quantum mechanics. This talk will review the recent progress
in attosecond ionization dynamics and time delays in photoemission and tunnel
ionization. Following the peak of an electron wavepacket (i.e. the group delay)
for determining time delays can be tricky and often misleading. We will discuss
why in the multi-photon or tunnel ionization regime the group delay (or the
related Wigner delay) gives the wrong explanation for the measured delay,
whereas in the single-photon ionization regime we can show experimentally
that the Wigner time delay can explain the general trend correctly although
it does not capture all the observed features.
Friday, April 7th 2017, 15:30
Ernest Rutherford Physics Building, Keys Auditorium (room 112)
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