Work and energy gain of heat-pumped quantized amplifiers

We investigate heat-pumped single-mode amplifiers of quantized fields in high-Q cavities based on non-inverted two-level systems. Their power generation is shown to crucially depend on the capacity of the quantum state of the field to accumulate useful work. By contrast, the energy gain of the field is shown to be insensitive to its quantum state. Analogies and differences with masers are explored

Event-sequence analysis of appraisals and coping during trapshooting performance

This study describes appraisal and coping patterns of trapshooters during competition, via post-performance retrospective verbal reports. Probabilities that an event (e.g., missed target) is followed by another event (e.g., negative appraisal) were calculated and state transitional diagrams were drawn. Event-sequences during critical and non-critical performance periods were compared. Negative appraisals were most likely before and after missed targets and hits with the second shot. Positive appraisals were most likely before problem-focused coping and after emotion-focused coping. These findings support the process view of coping by illustrating that athletes cope with a variety of situations via a complex set of appraisals

Power enhancement of heat engines via correlated thermalization in multilevel systems

We analyze a heat machine based on a periodically-driven quantum system permanently coupled to hot and cold baths. It is shown that the maximal power output of a degenerate $V$-type three-level heat engine is that generated by two independent two-level systems. For $N$ levels, this maximal enhancement is $(N-1)$-fold. Hence, level degeneracy is a thermodynamic resource that may effectively boost the power output. The efficiency, however, is not affected. We find that coherence is not an essential asset in multilevel-based heat machines. The existence of multiple thermalization pathways sharing a common ground state suffices for power enhancement