The Coherence Of Two Particles Interacting With The Same Macroscopic Medium

Quantum coherence is the basis of phenomena such as quantum interference and multibody entanglement,which play an important role in quantum physics and quantum information.This paper studied the two particles with spin-1/2 interact with a finite length one-dimensional array.Consider the single-particle coherence and two-particle coherence of two particles with spin-1/2.In this paper,the fringes visibility of single-particle and two-particle are used to measure single-particle coherence and double-particle coherence.Some innovative results have been achieved,the specific content and research results are as follows:1.Two particles located initially at the different position.(1)When the initial spin state of the particles is the completely entangled state(the spin initial states of the two particles are the same),due to the interaction between the particle and the one-dimensional spin array,the two-particle fringe visibility decreases monotonically as time increases and decays to zero asymptotically.The fringe visibility of single-particle is 0.(2)When the initial spin state of the particles is singlet state(the initial spin states of the two particles are different),due to the interaction between the particle and the one-dimensional spin array,the twoparticle fringe visibility first decreases and then increases as time increases,and finally becomes the initial value.In this case,the fringe visibility of single particle is also 0.(3)When the initial spin state of the particle is separable state(the two particles are in the pure state of equal weight),due to the interaction between the particle and the one-dimensional spin array,the two-particle fringe visibility increases monotonically as time increases and increases to 0.5 asymptotically.In this case,the single particle fringe visibility decreases with the increase of time.2.Two particles located initially at the same position.(1)When the initialspin state of the particles is the completely entangled state,due to the interaction between the particle and the one-dimensional spin array,the two-particle fringe visibility decreases monotonically as time increases and decays to zero asymptotically.When the initial positions of the two particles are the same,the fringes visibility of the two-particle decays faster than when the initial positions are different.The fringe visibility of single-particle is 0.(2)When the initial spin state of the particles is singlet state,the two-particle fringe visibility is always the initial value of 1.In this case,the fringe visibility of single particle is also 0.(3)When the initial spin state of the particle is separable state,due to the interaction between the particle and the one-dimensional spin array,the two-particle fringe visibility increases monotonically as time increases and increases to 0.5 asymptotically.When the initial positions of the two particles are the same,the fringes visibility of the two-particle increases faster than when the initial positions are different.In this case,the single particle fringe visibility decreases as time increases.