Abstract This paper systematically investigates the coherence dynamics of a two-qubit system under correlated channels. Through density matrix transformation and operator algebra derivation, we analyze the regulatory effects of memory properties of correlated amplitude damping, phase damping, and depolarization channels on three kinds of coherence, namely l 2 -norm coherence, Tsallis 2-relative entropy coherence, and Rényi 2-relative entropy coherence. The results show that phase damping and depolarization channels induce coherence freezing under perfect memory conditions, where coherence values remain invariant with channel damping rate variations. In partial memory environments, l 2 -norm coherence exhibits superior stability and retains coherence more efficiently than the other two coherence measures. In addition, we quantitatively evaluate the cohering and decohering power of these coherences under the correlated amplitude damping channel. This work provides theoretical support for anti-noise design of quantum technologies in open quantum systems.
Abstract This paper systematically investigates the coherence dynamics of a two-qubit system under correlated channels. Through density matrix transformation and operator algebra derivation, we analyze the regulatory effects of memory properties of correlated amplitude damping, phase damping, and depolarization channels on three kinds of coherence, namely l 2 -norm coherence, Tsallis 2-relative entropy coherence, and Rényi 2-relative entropy coherence. The results show that phase damping and depolarization channels induce coherence freezing under perfect memory conditions, where coherence values remain invariant with channel damping rate variations. In partial memory environments, l 2 -norm coherence exhibits superior stability and retains coherence more efficiently than the other two coherence measures. In addition, we quantitatively evaluate the cohering and decohering power of these coherences under the correlated amplitude damping channel. This work provides theoretical support for anti-noise design of quantum technologies in open quantum systems.
We study the dynamics of coherence-induced state ordering under incoherent channels, particularly four specific Markovian channels: amplitude damping channel, phase damping channel, depolarizing channel and bit flit channel for single-qubit states. We show that the amplitude damping channel, phase damping channel, and depolarizing channel do not change the coherence-induced state ordering by l 1 norm of coherence, relative entropy of coherence, geometric measure of coherence, and Tsallis relative α -entropies, while the bit flit channel does change for some special cases.
We study the dynamics of coherence-induced state ordering under incoherent channels, particularly four specific Markovian channels: amplitude damping channel, phase damping channel, depolarizing channel and bit flit channel for single-qubit states. We show that the amplitude damping channel, phase damping channel, and depolarizing channel do not change the coherence-induced state ordering by l1 norm of coherence, relative entropy of coherence, geometric measure of coherence, and Tsallis relative α-entropies, while the bit flit channel does change for some special cases.
Abstract In this paper, we investigate the cohering and decohering power of the one-qubit Markovian channels with respect to coherence measures based on the l 1 - norm, the Rényi α - relative entropy and the Tsallis α - relative entropy of coherence, respectively. The amplitude damping channel, phase damping channel, depolarizing channel, and flip channels are analytically calculated. It shows that the decohering power of the amplitude damping channel on the x , y , and z basis is equal to each other. The same phenomenon can be seen for the phase damping channel and the flip channels. The cohering power for the phase damping channel and the flip channels on the x , y basis also equals to that on the z basis. However, the cohering and decohering power of the depolarizing channel is independent to the reference basises. And the cohering power of the amplitude damping channel on the x , y basis is different to that on the z basis.
Quantum Coherence (QC) has a fundamental role in Quantum Mechanics (QM). It has been studied since the emergence of QM. However, this quantum feature is easily destroyed when a physical system interacts with the environment. Also, recently the quantum coherence has been highlighted because of the possibility of using its as a resource in the Quantum Information Science (QIS). In this work we study the QC flow of a qubit (two-level system) interacting with the environment modeled by quantum channels of noise that are very common in QIS. These channels represent some physical systems and are widely used for error correction studies. We calculate the QC by the l1-norm, doing this for the different channels seeking to relate it to the entanglement, which is also another key topic in QM. We note that in the amplitude damping channel the total QC is equal to the sum of the local and non-local parts and that the non-local part is equivalent to entanglement. For the phase damping channel, entanglement does not cover all non-local QC. Here there is a gap between them that may depend on the time and on the initial state. Besides, for the bit, phase, and bit phase flip channels the possibility and the conditions for invariance of QC are considered. Also, we notice that for the depolarizing channel we can use the qubit as a catalyst for the creation of non-local QC and entanglement. We, as well, observed that even initial states incoherent can lead to transient quantum coherence between system and environment. We also showed that the emergence of entanglement does not necessarily imply the destruction of QC. Furthermore, we investigated whether QC is lost or changed into other types of correlations and besides which initial conditions allow making quantum coherence robust to decoherence.
We make a thorough study of the spreading of quantum coherence (QC), as quantified by the l1-norm QC, when a qubit (a two-level quantum system) is subjected to noise quantum channels commonly appearing in quantum information science. We notice that QC is generally not conserved and that even incoherent initial states can lead to transitory system-environment QC. We show that for the amplitude damping channel the evolved total QC can be written as the sum of local and non-local parts, with the last one being equal to entanglement. On the other hand, for the phase damping channel (PDC) entanglement does not account for all non-local QC, with the gap between them depending on time and also on the qubit's initial state. Besides these issues, the possibility and conditions for time invariance of QC are regarded in the case of bit, phase, and bit-phase flip channels. Here we reveal the qualitative dynamical inequivalence between these channels and the PDC and show that the creation of system-environment entanglement does not necessarily imply in the destruction of the qubit's QC. We also investigate the resources needed for non-local QC creation, showing that while the PDC requires initial coherence of the qubit, for some other channels non-zero population of the excited state (i.e., energy) is sufficient. Related to that, considering the depolarizing channel we notice the qubit's ability to act as a catalyst for the creation of joint QC and entanglement, without need for nonzero initial QC or excited state population.
Abstract In this paper, we study coherence-induced state ordering with Tsallis relative entropy of coherence, relative entropy of coherence and l 1 norm of coherence, and give the sufficient conditions of the same state order induced by above coherence measures. First, we show that the above measures give the same ordering for single-qubit states in some special cases. Second, we consider some special states in a d -dimensional quantum system. We show that the above measures generate the same ordering for these special states. Finally, we discuss dynamics of coherence-induced state ordering under Markovian channels. We find amplitude damping channel changes the coherence-induced ordering even though for single-qubit states with fixed mixedness.