Abstract:
Quantum Otto refrigerator in adiabatic driving, for both high-temperature regime and low temperature regime, can be mapped to Feynman's ratchet and pawl model. Finite time cycle
period for a quantum Otto machine implies that either an adiabatic stroke or an isochoric process
precedes in finite time duration. The quantum Otto refrigerators under consideration consist of
two adiabatic strokes where the system (isolated from the heat reservoir) undergoes finite time
unitary transformation and two isochoric steps where the system may not reach thermal
equilibrium even at the respective ends of the two stages due to finite time interaction intervals.
The harmonic Otto refrigeration cycles of a modeled harmonic oscillator operating under the
conditions of maximum Ω-function was investigated. This trade-off objective function represents
a compromise between energy benefits and losses for a specific job, in adiabatic frequency
modulations. The study examines analytical expressions for the optimal performance both in the
high-temperature (classical) regime and in the low-temperature (quantum) limit. The analytical
expressions for coefficient of performance of the Otto cycle were derived. The variation of
quasistatic process and process at maximum power disturbs the usage of a refrigerator. This
means that in quasistatic process coefficient of performance is greater whereas power become
vanishes. As well as at maximum power, coefficient of performance minimized. Due to this gap
it should be optimized to analyze the performance of quantum Otto refrigerator. So, the study
introduces the optimized quantity for the two temperatures. In addition, it tries to scale optimum
value and maximum value. Finally, the coefficient of performance and power explained by
figure of merit for adiabatic driving.
