  In this paper, we analyse the quantum coherence behaviors of a single qubit
in the relativistic regime beyond the single-mode approximation. Firstly, we
investigate the freezing condition of quantum coherence in fermionic system. We
also study the quantum coherence tradeoff between particle and antiparticle
sector. It is found that there exists quantum coherence transfer between
particle and antiparticle sector, but the coherence lost in particle sector is
not entirely compensated by the coherence generation of antiparticle sector.
Besides, we emphatically discuss the cohering power and decohering power of
Unruh channel with respect to the computational basis. It is shown that
cohering power is vanishing and decohering power is dependent of the choice of
Unruh mode and acceleration. Finally, We compare the behaviors of quantum
coherence with geometric quantum discord and entanglement in relativistic
setup. Our results show that this quantifiers in two region converge at
infinite acceleration limit, which implies that this measures become
independent of Unruh modes beyond the single-mode approximations. It is also
demonstrated that the robustness of quantum coherence and geometric quantum
discord are better than entanglement under the influence of acceleration, since
entanglement undergoes sudden death.
