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arXiv:2604.24751

Semiclassical phases of charged spin-$1/2$ matter-wave interferometers in gravitational wave backgrounds

Nontapat Wanwieng, Apimook Watcharangkool

gr-qcquant-phSubmitted Apr 27, 2026• Announced Apr 28, 2026
v1 · Apr 27, 2026v2 · Aug 24, 2026
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Abstract

A matter wave propagating through curved spacetime accumulates phase that encodes both geometry and gauge structure. We develop a semiclassical framework for charged spin-$1/2$ matter-wave interferometers based on a WKB expansion of the covariant Dirac equation, in which the phase decomposes into dynamical, spin, and electromagnetic Aharonov-Bohm (AB) contributions. In a freely falling detector frame, all three channels are governed by local tidal fields. In a weak gravitational-wave (GW) background, the dynamical and spin phases probe the gravitoelectric and gravitomagnetic sectors of curvature, while the AB phase arises from curvature-induced electromagnetic fields obtained from Maxwell's equations in curved spacetime. For a Mach-Zehnder interferometer (MZI), all three responses are determined by the same tidal scale, $\ddot{h}_A \sim Ω^2_{gw}h_0$, and filtered by a common geometric kernel, while entering through distinct physical couplings. In particular, the AB contribution depends not only on the enclosed flux but also on spatial variations of the induced fields and exhibits an intrinsic frequency dependence set by the traversal time. These results provide a unified description of matter-wave interferometric phases in time-dependent GW backgrounds and identify complementary dynamical, spin, and electromagnetic pathways through which spacetime curvature imprints itself on quantum interference.

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15 pages

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Semiclassical phases of charged spin-1/21/21/2 matter-wave interferometers in gravitational wave backgrounds
A matter wave propagating through curved spacetime accumulates phase that encodes both geometry and gauge structure. We develop a semiclassical framework for charged spin-1/21/21/2 matter-wave interferometers based on a WKB expansion of the covariant Dirac equation, in which the phase decomposes into dynamical, spin, and electromagnetic Aharonov-Bohm (AB) contributions. In a freely falling detector frame, all three channels are governed by local tidal fields. In a weak gravitational-wave (GW) background, the dynamical and spin phases probe the gravitoelectric and gravitomagnetic sectors of curvature, while the AB phase arises from curvature-induced electromagnetic fields obtained from Maxwell's equations in curved spacetime. For a Mach-Zehnder interferometer (MZI), all three responses are determined by the same tidal scale, h¨A∼Ωgw2h0\ddot{h}_A \sim Ω^2_{gw}h_0h¨A​∼Ωgw2​h0​, and filtered by a common geometric kernel, while entering through distinct physical couplings. In particular, the AB contribution depends not only on the enclosed flux but also on spatial variations of the induced fields and exhibits an intrinsic frequency dependence set by the traversal time. These results provide a unified description of matter-wave interferometric phases in time-dependent GW backgrounds and identify complementary dynamical, spin, and electromagnetic pathways through which spacetime curvature imprints itself on quantum interference.
This paper explores a possible bridge between quantum matter-wave phase and spacetime curvature. The conservative starting point is the established relation between relativistic action, proper time, and quantum phase: for massive matter, the accumulated phase is determined by the proper-time integral along a worldline. In curved spacetime, this makes matter-wave phase sensitive to the metric geometry. Building on this relation, the paper asks whether matter-wave phase may acquire additional curvature-dependent contributions beyond the standard proper-time action phase. Such a contribution would not replace quantum mechanics or general relativity. Instead, it would represent a controlled covariant correction that becomes physically meaningful only if it produces calculable and falsifiable deviations in matter-wave interferometry, precision clock comparisons, gravitational redshift tests, or related high-precision experiments. The central proposal is that quantum phase, proper time, and spacetime curvature may be linked through a deeper action-geometric structure. In this view, phase is not treated merely as a formal parameter on a fixed background, but as a possible probe of how matter samples spacetime geometry. The paper does not claim a completed theory of everything. It identifies a concrete research direction: new physics may appear as measurable curvature-dependent corrections to phase accumulation. This work is Part III of the series The Geometry of Phase. Parts I and II reconstructed quantum interference and de Broglie matter waves from a phase-first perspective within standard physics. The present paper extends that line of thought toward curvature-coupled matter-wave phase and possible experimentally testable deviations. This manuscript is intended as a conceptual and exploratory foundations paper. It separates established reconstruction from speculative extension and provides a mathematical starting point for future tests of curvature-coupled quantum phase.
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This work explores the quantum propagator K(x,t)K(x,t)K(x,t) as a solution of the system's dynamical equation. We develop a generalized propagator framework in which the propagator is written in the form K=exp⁡ ⁣(R+iℏS)K=\exp\!\left(R+\frac{i}{\hbar}S\right)K=exp(R+ℏi​S), where SSS governs the semiclassical phase structure and RRR governs the amplitude transport and weighting of configurations. Starting from nonrelativistic quantum mechanics, the classical Hamilton--Jacobi equation emerges in the semiclassical limit, while RRR reduces to the logarithm of the Van Vleck determinant. The formalism is then extended to relativistic field theory and minisuperspace quantum cosmology using functional methods and generalized Hamiltonian constraints. Then the resulting semiclassical equations recover the corresponding classical dynamics along characteristic flows. In minisuperspace models, the formalism yields coupled equations for geometric and matter sectors analogous to semiclassical Wheeler--DeWitt systems. In semiclassical gravitational settings, the gravitational contribution may admit an entropy-like interpretation, consistent with thermodynamic weighting factors appearing in Euclidean gravitational path integrals. The resulting framework suggests a unified semiclassical description in which propagator phases encode dynamical evolution while amplitude functionals encode transport and configuration weighting. This perspective motivates viewing mechanics as a relation between the differential structure of spacetime and the differential structure of the space of dynamical configurations.
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