Optimal Probabilistic Work Extraction beyond the Free Energy Difference with a Single-Electron Device

Abstract

We experimentally realize protocols that allow to extract work beyond the free energy difference from a single electron transistor at the single thermodynamic trajectory level. With two carefully designed out-of-equilibrium driving cycles featuring kicks of the control parameter, we demonstrate work extraction up to large fractions of kBT or with probabilities substantially greater than 1/2, despite zero free energy difference over the cycle. Our results are explained in the framework of nonequilibrium fluctuation relations. We thus show that irreversibility can be used as a resource for optimal work extraction even in the absence of feedback from an external operator. arXiv:1810.06274v2 [cond-mat.stat-mech]

Maximum power and corresponding efficiency for two-level heat engines and refrigerators: optimality of fast cycles

“…Yet this hypothesis is not as crucial as it may appear. Indeed the feasibility of an infinitesimal Otto cycle relies on the ability of performing a very fast driving with respect to the typical time scales of the dynamics, a regime that can be achieved in several experimental setups [58,59]. Furthermore by taking the square-wave protocol shown in figure 1(b) characterized by finite time intervals τ H and τ C still fulfilling the ratio…”

“…In view of experimental implementations, we assess the impact of finite-time effects on our optimal protocol, finding that the maximum power does not decrease much if the external driving is not much slower than the typical dissipation rate induced by the baths [58,59]. Furthermore, we apply our optimal protocol to two experimentally accessible models, namely photonic baths coupled to a qubit [22, 60-63] and electronic leads coupled to a quantum dot [21,23,58,59,64,65].C , and Γ in (c) denotes *  G( ) H . 4 In principle, one can consider a broader family of controls including the possibility of rotating the Hamiltonian eigenvectors; however there is evidence that such an additional freedom does not help in two-level systems [45, 46].…”

Work exchange, geometric magnetization, and fluctuation-dissipation relations in a quantum dot under adiabatic magnetoelectric driving

“…By introducing a time-dependent component in this magnetic field, along with the variation of the gate voltage would lead to a scenario like the one studied in the present work. At finite T , the effects we have studied could be relevant in the implementation of driving protocols for thermal machines, [50][51][52][53][54][55][56] as well as in the discussion of shortcuts to adiabaticity. [57][58][59]…”

Thermodynamics and Steady State of Quantum Motors and Pumps Far from Equilibrium

“…In recent years, there has been a sustained growth in the interest in different forms of nanomachines. This was boosted by seminal experiments [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ], the blooming of new theoretical proposals [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], and the latest developments towards the understanding of the fundamental physics underlying such systems [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. Quantum mechanics has proven to be crucial in the description of a broad family of nanomachines, which can be put together under the generic name of “quantum motors” and “quantum pumps” [ 13 , 46 , 47 , 48 , 49 , 50 , ...…”