Accessible and inaccessible quantum coherence in relativistic quantum systems

Abstract

The quantum coherence of a multipartite system is investigated when some of the parties are moving with constant acceleration. Due to relativistic motion the quantum coherence is divided into two parts as accessible and inaccessible coherence. 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 relativistic motion. 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 W and star states in which both local and global coherences coexist. We find that under relativistic motion 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 where n < N qubits are subject to relativistic motion. 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.

Quantum entanglement and coherence of tripartite W state for Dirac fields under noisy channels in non-inertial frames

“…and C = 2 are consistent with the results of [10] and [27], respectively. When only one of the three parties moves with a uniform acceleration, the π -tangle (P = 0) is shown to be 0.176 in the infinite acceleration limit by [10], whereas for two of them in the infinite acceleration the our work provides p = » P 0 0.053 94…”

“…On the other hand, the quantum coherence of tripartite states in non-inertial frames has also been investigated intensively [24][25][26][27]. Wu and Zheng [24] studied the quantum coherence of GHZ-like states of multimode Dirac fields in the background of a Schwarzschild black hole.…”

“…Wu et al [26] studied the quantum coherence and its distribution of N-partite GHZ and W states of bosonic fields in non-inertial frames. In reference [27], the authors investigated the quantum coherence of the GHZ and W states when some of the parties are moving with constant acceleration. They found that the quantum coherence of these tripartite systems does not vanish in the infinite acceleration limit and derived analytic expressions for the quantum coherence of N-partite GHZ and W states in non-inertial frames.…”