The Applications Of Quantum Coherence In Quantum Information

Quantum coherence,which arises from quantum superposition,not only is a fundamental feature of quantum mechanics,but also plays an essential role in quantum information and computation.The information-theoretic quantification of quantum coherence is a successful application of quantum resource theory.Recently,relevant scholars have constructed a relatively complete theoretical framework of quantum coherence resources.Based on the framework,a large number of measures for quantum coherence have been proposed,and plenty of researchers have explored the applications of quantum coherence in many fields with the help of these measures,such as quantum metrology,quantum thermodynamics and quantum biology.These exciting results are the roots which motivate us to study the application of quantum coherence in quantum information,and we have obtained two meaningful results.Firstly,we established two complementarity relations for the relative entropy of coherence in quantum information processing,i.e.,quantum dense coding and teleportation.We gave an uncertainty-like expression relating local quantum coherence to the capacity of optimal dense coding for bipartite system,along with the verification that this relation can also be applied to the case of dense coding by using unital memoryless noisy quantum channels.Moreover,the relation between local quantum coherence and teleportation fidelity for two-qubit system was given.Secondly,we investigated the enhancement of nonlocal advantage of quantum coherence(NAQC)for two-qutrit system suffering from the global depolarising noise or the global dephasing noise by using of the measurement reversal operators or the weak measurement operators.When the measurement reversal operators or the weak measurement operators were applied,it was found that NAQC of two-qutrit system that subjected to the global depolarising noise can be significantly enhanced.However,the measurement reversal operators or the weak measurement operators cannot enhance NAQC of two-qutrit system which undergoes the global dephasing noise.