https://doi.org/10.1140/epjc/s10052-025-14832-4
Regular Article - Theoretical Physics
Entangled Unruh–DeWitt detectors amplify quantum coherence
1
Department of Physics, Liaoning Normal University, 116029, Dalian, China
2
Lanzhou Center for Theoretical Physics, Key Laboratory of Theoretical Physics of Gansu Province, Key Laboratory of Quantum Theory and Applications of MoE, Gansu Provincial Research Center for Basic Disciplines of Quantum Physics, Lanzhou University, 730000, Lanzhou, China
3
Institute of Theoretical Physics and Research Center of Gravitation, School of Physical Science and Technology, Lanzhou University, 730000, Lanzhou, China
a
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Received:
15
July
2025
Accepted:
18
September
2025
Published online:
3
October
2025
Abstract
We explore the quantum coherence between a pair of entangled Unruh–DeWitt detectors, interacting with a quantum field, using a nonperturbative approach in a (3+1)-dimensional Minkowski spacetime with instantaneous switching (
-switching). It is intriguing to observe that for a maximally entangled state, increasing the coupling strength enhances the detectors’ initial quantum coherence while simultaneously causing a monotonic decrease in their initial entanglement. This reveals a remarkable phenomenon: through nonperturbative interactions, entangled Unruh–DeWitt detectors can exhibit a dual effect-amplifying quantum coherence while degrading quantum entanglement. This finding stands in stark contrast to previous studies based on perturbative methods or Gaussian switching functions, which generally concluded that interactions between detectors and the field lead to a simultaneous degradation of quantum coherence and entanglement due to environmental decoherence. Notably, while initially separable detectors successfully harvest quantum coherence from the vacuum, entanglement extraction remains fundamentally prohibited. These contrasting behaviors underscore the fundamental distinction between coherence and entanglement as quantum resources, and highlight their complementary roles in field-detector interactions.
© The Author(s) 2025
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