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DY: Fachverband Dynamik und Statistische Physik
DY 48: Statistical Physics far from Thermal Equilibrium
DY 48.8: Vortrag
Donnerstag, 19. März 2020, 11:30–11:45, ZEU 147
A quantum heat engine based on dynamical material design — •Gerhard Tulzer1, Levan Chotorlishvili2, Martin Hoffmann1, Robert Zillich1, Jamal Berakdar2, and Arthur Ernst1 — 1Institute for Theoretical Physics, Johannes Kepler University, Linz, Austria — 2Institute of Physics, Marthin Luther University Halle-Wittenberg, Halle (Saale), Germany
We investigate the practical usability of a magneto-electric working substance (Cr2O3) for a quantum Otto cycle. The new approach here is the exploitation of a new type of driving during the adiabatic work strokes, where non-linear phonon processes controlled by high-intensity terahertz optical pulses are employed to induce structural changes in the magnetic ordering of the system, being described as a spin chain with spin-3/2. The isochoric heating and cooling strokes are based on the coupling to a phonon thermostat. This type of system appears to be very promising due to its swiftness, but still needs a thorough investigation due to the nonlinearity in its dynamics and the much richer energy spectrum compared to toy models.
After confirming that we actually obtain a thermodynamic cycle we investigate the practical feasibility using the Lindblad master equation. Two quantities of interest in this regard are the efficiency as well as the output power and their relation to the experimental control parameters. We then consider the effects of different thermostat settings, and also investigate relaxation times and work stroke duration in order to find the optimal timing for high efficiency and output power.