Due to mutual interaction atoms can self-organize and form a space
crystal. In 2012 Frank Wilczek asked the question if a similar
phenomenon can occur in the time domain, i.e. if a many-body system can
self-organize in time and spontaneously start a periodic motion.
Original Wilczek idea turned out to be impossible to realize, however,
it became an inspiration to other scientists.
In 2015 the first article on the so-called discrete time crystals was published, Sacha, Phys. Rev. A
where it was shown that periodically driven interacting atoms can
spontaneously self-organize and start moving with a period twice longer
than the driving period. A year later independent ideas on discrete
time crystals were published. In 2017 two groups performed experiments
where discrete time crystals were realized. The results were announced
in Nature magazine, J. Zhang et al.
and S. Choi i et al
, see also News and Views
in Nature and News of Polish Sicience
or a lecture in CFT PAN
. and in Vlinus
, Physics World 2020
In our group we have been carrying the research on time crystals from
the very beginning. It is already known that time crystals, similarly
as space crystals, can be conductors or insulators, Sacha, Sci. Rep. 2015
A book on "Time Crystals"
and lecture series on "TIME CRYSTALS" - YouTube
Cold Quantum Gases
Development in trapping and cooling
of dilute atomic gases allows experimentalists to obtain Bose-Einstein
condensates of bosonic atoms and also to reach transition to a
superfluid state in cold fermionic gases. In our group we do
theoretical research in such degenerate atomic gases. Our interests
concern: collective excitation in atomic gases
(such as solitons and vortices), cold gases in optical lattice
potentials (i.e. realizations of solid state models in atomic gases),
analysis of a measurement problem in the quantum many body systems,
possibilitiesof realization of field theory models.
Ionization in Strong Laser Fields
Recent development in the laser
technology allow experimental studies of high order harmonic
generation, above threshold ionization and multi-electron effects, such
as a non-sequential double ionization. While the single ionization of
atoms or molecules, as well as the high order harmonic generation can
be described within a single active electron model, such an
approximation in the case of multiple ionization and laser intensity
below the saturation value gives ionization rates that are much smaller
than experimentally observed, indicating that interactions between
electrons are important. Having that in mind, in our group we consider
the multiple ionization of atoms and molecules both from a classical and a
quantum point of view.
- NCN MAESTRO 2021/42/A/ST2/00017 (2022-2027).
- NCN OPUS 2018/31/B/ST2/00349 (2019-2022).
- Discovery Project,
Ausralian Research Council, partner of prof. Peter Hannaford, Swinburne
University of Technology, Melbourne, (2019-2023).
- QuantEra 2017/25/Z/ST2/03027 (2018-2020).