Projekteja vuodessa
Abstrakti
We study the thermodynamic performance of a finitetime nonregenerative quantum Stirlinglike cycle used as a heat engine. We consider specifically the case in which the working substance (WS) is a twolevel system (TLS). The Stirling cycle is made of two isochoric transformations separated by a compression and an expansion stroke during which the WS is in contact with a thermal reservoir. To describe these two strokes we derive a nonMarkovian master equation which allows to study the realtime dynamics of a driven open quantum system with arbitrary fast driving. Following the realtime dynamics of the WS using this master equation, the endpoints of the isotherms can deviate from the equilibrium thermal states. The role of this deviation in the performance of the heat engine is addressed. We found that the finitetime dynamics and thermodynamics of the cycle depend nontrivially on the different time scales at play. In particular, driving the WS at a time scale comparable to the resonance time of the bath enhances the performance of the cycle and allows for an efficiency higher than the efficiency of the quasistatic cycle, but still below the Carnot bound. However, by adding thermalization of the WS with the baths at the end of compression/expansion processes one recovers the conventional scenario in which efficiency decreases by speeding up the processes. In addition, the performance of the cycle is dependent on the compression/expansion speeds asymmetrically, which suggests new freedom in optimizing quantum heat engines. The maximum output power and the maximum efficiency are obtained almost simultaneously when the realtime endpoints of the compression/expansion processes are considered instead of the equilibrium thermal endpoint states. However, the net extractable work always declines by speeding up the drive.
Alkuperäiskieli  Englanti 

Artikkeli  033034 
Sivumäärä  17 
Julkaisu  New Journal of Physics 
Vuosikerta  23 
Numero  3 
DOI  pysyväislinkit  
Tila  Julkaistu  maalisk. 2021 
OKMjulkaisutyyppi  A1 Julkaistu artikkeli, soviteltu 
Sormenjälki
Sukella tutkimusaiheisiin 'Finitetime quantum Stirling heat engine'. Ne muodostavat yhdessä ainutlaatuisen sormenjäljen.Projektit
 2 Päättynyt

QED RADDESS/Paraoanu
Paraoanu, G., Björkman, I., McCord, J. & Sultanov, A.
01/01/2020 → 31/12/2022
Projekti: Academy of Finland: Other research funding

CoE QTF/Paraoanu
Paraoanu, G., Dogra, S., Petrovnin, K., Lan, D., McCord, J. & Cattaneo, M.
01/01/2018 → 31/12/2020
Projekti: Academy of Finland: Other research funding