Response of Hellinger-distance based coherence to weak decoherence in two-flavor neutrino oscillations
Abstract
We evaluate the Hellinger-distance coherence of the two-flavor neutrino state subject to Lindblad damping of the mass-eigenstate interference term, and obtain a closed expression in terms of the flavor-basis density-matrix elements. In the two-flavor vacuum treatment with negligible wave-packet separation, the undamped state is pure, and the smallest eigenvalue of the damped state grows linearly with ε=1−κ, where κ=e−ΓL. An expansion about the pure state then yields a nonanalytic √ε correction to the Hellinger coherence, with coefficient K=2√2 usin2θ/√(1−2u), whereas the flavor-transition probability, the l1 coherence, the concurrence, the entanglement of formation and the local quantum Fisher information all respond linearly in ε. Using representative Daya Bay, KamLAND and MINOS working points together with a current 90% C.L. bound on energy-independent damping, we find fractional changes in the Hellinger coherence of 0.18%, 9.40% and 21.51%, against 0.0009%, 0.43% and 1.81% for the concurrence. The comparison concerns the response of the quantifiers to the damping parameter and carries no implication about experimental resolution. The same mechanism operates, with a different coefficient, for a correlated dephasing channel acting on the flavor coherence, where the non-Markovian regime produces damped revivals.
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BibTeX
@misc{rai2026response,
title = {{Response of Hellinger-distance based coherence to weak decoherence in two-flavor neutrino oscillations}},
author = {Saurabh Rai and Nilakshi Das and Tejhas Kapoor},
howpublished = {HAL},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.27697},
eprint = {2609.27697},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05780403v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Response of Hellinger-distance based coherence to weak decoherence in two-flavor neutrino oscillations
AU - Saurabh Rai
AU - Nilakshi Das
AU - Tejhas Kapoor
PY - 2026
DA - 2026/09/23
PB - HAL
DO - 10.48550/arxiv.2609.27697
UR - https://hal.science/hal-05780403v1
AB - We evaluate the Hellinger-distance coherence of the two-flavor neutrino state subject to Lindblad damping of the mass-eigenstate interference term, and obtain a closed expression in terms of the flavor-basis density-matrix elements. In the two-flavor vacuum treatment with negligible wave-packet separation, the undamped state is pure, and the smallest eigenvalue of the damped state grows linearly with ε=1−κ, where κ=e^−ΓL. An expansion about the pure state then yields a nonanalytic √ε correction to the Hellinger coherence, with coefficient K=2√2 usin2θ/√(1−2u), whereas the flavor-transition probability, the l_1 coherence, the concurrence, the entanglement of formation and the local quantum Fisher information all respond linearly in ε. Using representative Daya Bay, KamLAND and MINOS working points together with a current 90% C.L. bound on energy-independent damping, we find fractional changes in the Hellinger coherence of 0.18%, 9.40% and 21.51%, against 0.0009%, 0.43% and 1.81% for the concurrence. The comparison concerns the response of the quantifiers to the damping parameter and carries no implication about experimental resolution. The same mechanism operates, with a different coefficient, for a correlated dephasing channel acting on the flavor coherence, where the non-Markovian regime produces damped revivals.
ER -