Characterizing quantum precision enhancement for multiple currents in open quantum systems
Abstract
The kinetic uncertainty relation (KUR) constrains fluctuations of individual currents in classical nonequilibrium systems in terms of the dynamical activity, which quantifies the average number of transitions per unit of time. Here, we derive a multi-current KUR (MKUR) establishing the precision limit for multiple currents generated in classical stochastic processes in the nonequilibrium steady state. We then apply our theory to identify quantum devices whose correlated current fluctuations surpass this classical limit by comparing the quantum system to a classical emulator with the same average currents in the steady state. In this way, violations of the emulator's MKUR have a clear physical meaning, i.e., that the quantum-coherent evolution reduces joint current fluctuations below what is possible for a classical Markovian system with the same energy-level structure and incoherent resources. Since the MKUR incorporates correlations between currents, its violation pinpoints nonclassical fluctuations in parameter regimes where the single-current KUR is satisfied. We illustrate the essential and complementary role of these bounds for characterizing joint current precision with two examples: a coherently driven two-level system and an experimentally motivated model of a three-level heat engine subject to parasitic environmental couplings.
Related
- Precision Electroweak Physics of Neutral Currents Below the Z-pole
- Singlet-doublet transitions and Josephson currents in a superconducting ring with a quantum dot
- Bias-driven circular currents in a quantum ring: Effects of electron-electron and electron-phonon interactions
- Multiple Current Enhancement Regimes and Interaction Induced Re-entrant Transport in a Quasiperiodic Hubbard Ring with Antiferromagnetic Order
- Generation of pure spin currents via nonadiabatic quantum pumping in an antiferromagnetic chain
BibTeX
@misc{mahadeviya2026characterizing,
title = {{Characterizing quantum precision enhancement for multiple currents in open quantum systems}},
author = {Khalak Mahadeviya and Sheikh Parvez Mandal and Mahasweta Pandit and Javier Prior and Mark T. Mitchison and Saulo V. Moreira},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.35982},
eprint = {2609.35982},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.35982},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Characterizing quantum precision enhancement for multiple currents in open quantum systems
AU - Khalak Mahadeviya
AU - Sheikh Parvez Mandal
AU - Mahasweta Pandit
AU - Javier Prior
AU - Mark T. Mitchison
AU - Saulo V. Moreira
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.35982
UR - https://arxiv.org/abs/2609.35982
AB - The kinetic uncertainty relation (KUR) constrains fluctuations of individual currents in classical nonequilibrium systems in terms of the dynamical activity, which quantifies the average number of transitions per unit of time. Here, we derive a multi-current KUR (MKUR) establishing the precision limit for multiple currents generated in classical stochastic processes in the nonequilibrium steady state. We then apply our theory to identify quantum devices whose correlated current fluctuations surpass this classical limit by comparing the quantum system to a classical emulator with the same average currents in the steady state. In this way, violations of the emulator's MKUR have a clear physical meaning, i.e., that the quantum-coherent evolution reduces joint current fluctuations below what is possible for a classical Markovian system with the same energy-level structure and incoherent resources. Since the MKUR incorporates correlations between currents, its violation pinpoints nonclassical fluctuations in parameter regimes where the single-current KUR is satisfied. We illustrate the essential and complementary role of these bounds for characterizing joint current precision with two examples: a coherently driven two-level system and an experimentally motivated model of a three-level heat engine subject to parasitic environmental couplings.
ER -