  The quantum coherence of a multipartite system is investigated when some of
the parties are moving with uniform acceleration and the analysis is carried
out using the single mode approximation. Due to acceleration the quantum
coherence is divided into two parts as accessible and inaccessible coherence
and the entire analysis has been carried out in the single-mode approximation.
First we investigate tripartite systems, considering both GHZ and W-states. We
find that the quantum coherence of these states does not vanish in the limit of
infinite acceleration, rather asymptoting to a non-zero value. These results
hold for both single- and two-qubit acceleration. In the GHZ and W-states the
coherence is distributed as correlations between the qubits and is known as
global coherence. But quantum coherence can also exist due to the superposition
within a qubit, the local coherence. To study the properties of local coherence
we investigate separable state. The GHZ state, W-state and separable states
contain only one type of coherence. Next we consider the $W \bar{W}$ and star
states in which both local and global coherences coexist. We find that under
uniform acceleration both local and global coherence show similar qualitative
behaviour. Finally we derive analytic expressions for the quantum coherence of
N-partite GHZ and W-states for n < N accelerating qubits. We find that the
quantum coherence of a multipartite GHZ state falls exponentially with the
number of accelerated qubits, whereas for multipartite W-states the quantum
coherence decreases only polynomially. We conclude that W-states are more
robust to Unruh decoherence and discuss some potential applications in
satellite-based quantum communication and black hole physics.
