Theory Department
Max Planck Institute of Microstructure Physics
1997    
1998    
1999    
2000    
2001    
2002    
2003    
2004    
2005    
2006    
2007    
2008    
2009    
2010    
2011    
2012    
2013    
2014    
2015    
2016    
2017    
2018    
2019    
2020    
2021    
Azimi, M., Chotorlishvili, L., Mishra, S. K., Vekua, T., Hübner, W., Berakdar, J.

Quantum Otto heat engine based on a multiferroic chain working substance
New Journal of Physics 16, (6),pp 063018/1-22 (2014)
We study a quantum Otto engine operating on the basis of a helical spin-1/2 multiferroic chain with strongly coupled magnetic and ferroelectric order parameters. The presence of a finite spin chirality in the working substance enables steering of the cycle by an external electric field that couples to the electric polarization. We observe a direct connection between the chirality, the entanglement and the efficiency of the engine. An electric-field dependent threshold temperature is identified, above which the pair correlations in the system, as quantified by the thermal entanglement, diminish. In contrast to the pair correlations, the collective many-body thermal entanglement is less sensitive to the electric field, and in the high temperature limit converges to a constant value. We also discuss the correlations between the threshold temperature of the pair entanglement, the spin chirality and the minimum of the fidelities in relation to the electric and magnetic fields. The efficiency of the quantum Otto cycle shows a saturation plateau with increasing electric field amplitude.

TH-2014-30