Distribution And Assisted Extraction Of Quantum Coherence

Quantum coherence,exhibiting the fundamental feature of quantum superposition,marks the difference of quantum physics from classical physics.As an important resource,quantum coherence has practical applications in many physics research fields.Especially in the field of quantum information,the realization of quantum operations closely depends on the maintenance and transformation of coherence.The decoherence resulting from the interaction between quantum systems and environment brings great difficulties to the implementation of quantum information processing.Therefore it is signifificant to study the quantum coherence in open systems.In this thesis,we introduce the concept of quantum coherence and its measures,reveal the relationship between quantum coherence,entanglement,discord and dissonance,and study the distribution of quantum coherence and quantum correlation in multipartite systems.Based on the linear optical system,the experimental proposal on how to detect and verify the distributions is given.In addition,we study the problem of the assisted extraction of quantum coherence in open systems,and show the important influence of the environment and the role of quantum correlation in the assisted extraction process of quantum coherence.In the first chapter,we introduce the research background,research content and significance.In the second chapter,we introduce some basic concepts of quantum information and quantum mechanics,definition of coherence,many measures of quantum coherence.In Chapter 3,we introduce some experimental devices commonly used in linear optical experiments and several schemes of quantum channel.The method of quantum state tomography is also given in this chapter.In Chapter 4,we study the distribution of quantum coherence,quantum entanglement,quantum discord and quantum dissonance in multipartite systems.Based on the linear optical system,we propose an experimental setup to verify the distributions,and the measurement method is given.We use a linear optical platform to prepare a three-qubit quantum entangled state.In this state,we study the distribution of quantum coherence,quantum entanglement,quantum discord,and quantum dissonance.In Chapter 5,we study the problem of assisted extraction of quantum coherence in open systems by using the numerical method of hierarchy equation.In Chapter 6,we give the conclusions.