Past colloquia and seminars


Cooling quantum matter by non-linear driving

General public Colloquium / Congress / Forum
22.05.2019 17:15 - 18:15

Generically, driving a many-body system by radiation simply induces heating. However, by using smart driving protocols one can actually achieve the exact opposite: very cold states of quantum matter. Even though being out-of-equilibrium, those may have an extremely low effective temperature. I will review several new insights into techniques that can be used to achieve such cold states and the physical mechanisms at play.
In particular I will discuss the so-called thermal mixing method, by which one generates a cool steady state of electronic spins that then cool and hyperpolarize nuclear spins - a crucial step to enhance the contrast in NMR. Interestingly the cooling effect is optimized by tuning the system to its many-body localization transition. Another promising cooling scheme uses optical doping from a narrow core band into a Hubbard band and thereby generates excited states with so low temperatures that ordering is induced. These ideas are first steps towards the ultrafast induction and control of magnetic or electronic order on demand. The physical principles involved apply to a variety of other condensed matter systems, as well as to cold (fermionic) atoms which have been notoriously difficult to cool.

When? 22.05.2019 17:15 - 18:15
Where? PER 08 0.51
Chemin du Musée 3
1700 Fribourg
speaker Dr. Markus Müller, PSI Villigen
Contact Département de Physique
Akrap Ana
Chemin du Musée 3
1700 Fribourg
026 300 91 08