aiqbench analysis
This research presents an optimal control strategy for quantum refrigerators by randomizing the measurement phase to eliminate coherence-induced suppression of cooling power. By cycling phases separated by $\pi$, the study achieves a 32% increase in stationary cooling power without altering the energy efficiency ratio, offering a practical method to enhance quantum thermal devices.
Optimal phase control of a measurement-assisted quantum refrigerator
arXiv:2610.04237v1 Announce Type: new Abstract: A tilted nonselective measurement can close the upper transition of a three-level quantum refrigerator, but it also generates coherence that feeds back on the populations and suppresses the cooling current. We formulate randomized open-loop control of the measurement azimuthal phase \(\alpha\), sampled independently at each event from a probability distribution \(P(\alpha)\), while keeping the event rate, polar angle, and single-event population-transfer probability fixed. Direct population transfer is phase independent, whereas the coherence source carries the factor \(e^{-i\alpha}\). Exact elimination of the stationary coherence gives \(0\leq k_{\rm eff}[P]\leq A_m\), where \(k_{\rm eff}[P]\) is the effective population-transfer rate between the upper levels and \(A_m\) is the bare direct mixing rate. When the fixed measurement couples populations and coherence, the upper bound is attained if and only if \(\langle e^{i\alpha}\rangle_P=0\), where \(\langle\cdot\rangle_P\) denotes an average over the phase distribution. The minimal realization uses two equally weighted phases separated by \(\pi\): the population-to-coherence source and its return to the populations then vanish at the generator level, while the full direct mixing remains. Because the cold current increases strictly with \(k_{\rm eff}\) in the refrigeration window, the same condition maximizes the stationary cooling power over the independent random-phase distributions considered here. For one representative parameter set, phase cycling increases the fixed-gap cooling power by about \(32\%\) relative to a fixed-phase measurement, while leaving the ratio of extracted cold heat to supplied measurement energy unchanged.
Abstract:A tilted nonselective measurement can close the upper transition of a three-level quantum refrigerator, but it also generates coherence that feeds back on the populations and suppresses the cooling current. We formulate randomized open-loop control of the measurement azimuthal phase \(\alpha\), sampled independently at each event from a probability distribution \(P(\alpha)\), while keeping the event rate, polar angle, and single-event population-transfer probability fixed. Direct population transfer is phase independent, whereas the coherence source carries the factor \(e^{-i\alpha}\). Exact elimination of the stationary coherence gives \(0\leq k_{\rm eff}[P]\leq A_m\), where \(k_{\rm eff}[P]\) is the effective population-transfer rate between the upper levels and \(A_m\) is the bare direct mixing rate. When the fixed measurement couples populations and coherence, the upper bound is attained if and only if \(\langle e^{i\alpha}\rangle_P=0\), where \(\langle\cdot\rangle_P\) denotes an average over the phase distribution. The minimal realization uses two equally weighted phases separated by \(\pi\): the population-to-coherence source and its return to the populations then vanish at the generator level, while the full direct mixing remains. Because the cold current increases strictly with \(k_{\rm eff}\) in the refrigeration window, the same condition maximizes the stationary cooling power over the independent random-phase distributions considered here. For one representative parameter set, phase cycling increases the fixed-gap cooling power by about \(32\%\) relative to a fixed-phase measurement, while leaving the ratio of extracted cold heat to supplied measurement energy unchanged.
arXiv:2610.04237 [quant-ph]
(or arXiv:2610.04237v1 [quant-ph] for this version)
https://doi.org/10.48550/arXiv.2610.04237 Focus to learn more arXiv-issued DOI via DataCite (pending registration)
arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website.
Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them.
Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs.
Full text under the publisher's open licence · 320 words
