Quantum fluctuation theorems provide fundamental constraints on entropy production but rely on a trajectory-based description that becomes problematic in the presence of coherence and incompatible measurements. While deviations from standard fluctuation relations in quantum regimes are often attributed to coherence, the precise nonclassical mechanism underlying such effects remains under active discussion. In this work, we investigate contextual interference effects in nonequilibrium thermodynamics using a minimal analytically solvable two-qubit heat-exchange model with a phase-tunable partial-swap interaction. Employing a coherence-preserving Kirkwood–Dirac (KD) quasiprobability formulation of energy exchange, we identify a single correction term, Ξ ctx , that quantifies deviations from the conventional fluctuation-theorem symmetry. We show that this correction originates from interference between incompatible measurement contexts within the degenerate single-excitation subspace and vanishes both in the incoherent limit and at thermal equilibrium. The resulting expression is fully analytic, depends on experimentally tunable parameters, and explicitly connects entropy-current fluctuations to phase-sensitive coherence effects. Our results provide an operationally accessible signature of KD-interference contributions in quantum thermodynamics and demonstrate that coherence, when combined with measurement incompatibility, induces a well-defined correction to fluctuation relations. This establishes a minimal framework linking contextual interference and thermodynamic irreversibility and suggests experimentally feasible routes for probing such effects on current quantum platforms.
Karim Ghorbani (Wed,) studied this question.