Fig. 3: Dynamics of the mean population of the load: experimental results. | npj Quantum Information

Fig. 3: Dynamics of the mean population of the load: experimental results.

From: Single-atom energy-conversion device with a quantum load

Fig. 3

ac, Experimentally measured mean phonon occupation number of the load in a non‘thermal-type’ state, 〈nL, versus the number of engine cycles Nc. a compares an engine cycle (red dotted line with ) with a reversed, cooling cycle (blue dot-dashed line with ), with \({p}_{D}^{{\mathcal{A}}}=0.5\) in both cases. b, Performance of engine cycles characterized by different \({p}_{{\rm{D}}}^{{\mathcal{A}}}\), that is, the population in state D on state resetting in stroke (I), with \({p}_{{\rm{D}}}^{{\mathcal{A}}}=0.5\) (red dotted line with ), \({p}_{{\rm{D}}}^{{\mathcal{A}}}=0.32\) (blue dot-dashed line with ) and \({p}_{{\rm{D}}}^{{\mathcal{A}}}=0.15\) (green continuous line with ). For larger \({p}_{{\rm{D}}}^{{\mathcal{A}}}\), the rate of increase of 〈nL per engine cycle is greater. c, Performance of engine cycles for two different engine–load coupling protocols, rapid adiabatic passage (black ) and resonant sideband transfer (blue ), both using \({p}_{{\rm{D}}}^{{\mathcal{A}}}=0.32\). In all panels, the lines connecting the data points are only to guide the eye. The error bars represent one sigma standard deviation and contain both statistical and systematic errors, obtained by parameter estimation using the least-squares method (see the Methods for details). The reduced χ2 value that gives the error bars depends strongly on the number of data points in a given fit, which ranges from 25 to 200. In all cases, the phase error that enters in the χ2 is 0.1, estimated from >150 replicates.

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