Finite quantum pumps for phase-locked parametric amplification: requirements for quantum-battery work sources
- 1University of Gdańsk
Abstract
Quantum batteries have been proposed as locally precharged work sources for superconducting quantum technologies, suggesting a route to reduce continuously supplied microwave drives. Here we ask what a finite bosonic pump must provide to replace the pump tone of a nondegenerate parametric amplifier during a readout window. Quantizing the pump exposes a resource distinction hidden in the classical description: stored energy and the ordinary marginal signal response can survive pump phase twirling, whereas a reproducible phase-locked signal-idler field requires pump coherences in the number sectors coupled by the mixing process. In a closed trilinear model, a coherent pump and its number-matched phase-twirled counterpart generate the same number-like marginal observables, but only the coherent pump produces anomalous two-mode coherence and an EPR-squeezed interference dip. Including leakage, we collect the emitted fields into cascaded temporal modes. At matched collector bandwidth, the coherent pump gives the interference certifier I min ( f ) = 0.553 , whereas the phase-randomized control gives I min ( f ) ≃ 1.94 . A weak seeded-signal analysis shows more sharply that an exact pump phase twirl leaves the collected signal marginal invariant by phase covariance while eliminating the anomalous signal-idler coherence. A finite-cutoff scan also indicates that weak amplitude squeezing can modestly deepen the phase-sensitive dip by reducing pump-number fluctuations while preserving most of the coherent displacement. Thus, for the three-wave-mixing pump families studied here, adjacent-number pump coherence is the resource that establishes a phase-locked joint amplifier field, rather than a prerequisite for energy transfer or ordinary marginal signal response.
Versions
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BibTeX
@article{ahmadi2026finite,
title = {{Finite quantum pumps for phase-locked parametric amplification: requirements for quantum-battery work sources}},
author = {Borhan Ahmadi},
journal = {New Journal of Physics},
year = {2026},
month = oct,
doi = {10.1088/1367-2630/aeb4e6},
url = {https://iopscience.iop.org/article/10.1088/1367-2630/aeb4e6},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Finite quantum pumps for phase-locked parametric amplification: requirements for quantum-battery work sources
AU - Borhan Ahmadi
PY - 2026
DA - 2026/10/27
JO - New Journal of Physics
DO - 10.1088/1367-2630/aeb4e6
UR - https://iopscience.iop.org/article/10.1088/1367-2630/aeb4e6
AB - Quantum batteries have been proposed as locally precharged work sources for superconducting quantum technologies, suggesting a route to reduce continuously supplied microwave drives. Here we ask what a finite bosonic pump must provide to replace the pump tone of a nondegenerate parametric amplifier during a readout window. Quantizing the pump exposes a resource distinction hidden in the classical description: stored energy and the ordinary marginal signal response can survive pump phase twirling, whereas a reproducible phase-locked signal-idler field requires pump coherences in the number sectors coupled by the mixing process. In a closed trilinear model, a coherent pump and its number-matched phase-twirled counterpart generate the same number-like marginal observables, but only the coherent pump produces anomalous two-mode coherence and an EPR-squeezed interference dip. Including leakage, we collect the emitted fields into cascaded temporal modes. At matched collector bandwidth, the coherent pump gives the interference certifier I min ( f ) = 0.553 , whereas the phase-randomized control gives I min ( f ) ≃ 1.94 . A weak seeded-signal analysis shows more sharply that an exact pump phase twirl leaves the collected signal marginal invariant by phase covariance while eliminating the anomalous signal-idler coherence. A finite-cutoff scan also indicates that weak amplitude squeezing can modestly deepen the phase-sensitive dip by reducing pump-number fluctuations while preserving most of the coherent displacement. Thus, for the three-wave-mixing pump families studied here, adjacent-number pump coherence is the resource that establishes a phase-locked joint amplifier field, rather than a prerequisite for energy transfer or ordinary marginal signal response.
SN - 1367-2630
ER -