Impact of Distribution Fairness Degree and Entanglement Degree on Cooperation

We explore the impact of distributional fairness degree and entanglement degree on the cooperation between different players by investigating a modified prisoner＇s dilemma game. We not only introduce a new concept of distributional fairness degree, but also obtain the cooperation conditions for overcoming dilemma in terms of fairness and entanglement inequalities. It is demonstrated that distributional fairness can be of fundamental importance to promote cooperation with the help of quantum entanglement.

Entanglement and Sudden Death for a Two-Mode Radiation Field Two Atoms

The effect of the field–field interaction on a cavity containing two qubit(TQ)interacting with a two mode of electromagnetic field as parametric amplifier type is investigated.After performing an appropriate transformation,the constants of motion are calculated.Using the Schrödinger differential equation a system of differential equations was obtained,and the general solution was obtained in the case of exact resonance.Some statistical quantities were calculated and discussed in detail to describe the features of this system.The collapses and revivals phenomena have been discussed in details.The Shannon information entropy has been applied for measuring the degree of entanglement(DE)between the qubits and the electromagnetic field.The normal squeezing for some values of the parameter of the field–field interaction is studied.The results showed that the collapses disappeared after the field–field terms were added and the maximum values of normal squeezing decrease when increasing of the field–field interaction parameter.While the revivals and amplitudes of the oscillations increase when the parameter of the field–field interaction increases.Degree of entanglement is partially more entangled with increasing of the field-field interaction parameter.The relationship between revivals,collapses and the degree of entanglement(Shannon information entropy)was monitored and discussed in the presence and absence of the field–field interaction.

Effect of non-spherical atmospheric charged particles and atmospheric visibility on performance of satellite-ground quantum link and parameters simulation

In order to study the relationship between the non-spherical atmospheric charged particles and satellite-ground quantum links attenuation. The relationship among the particle concentration, equivalent radius, charge density of the charged particle, the attenuation coefficient and entanglement of the satellite-ground quantum link can be established first according to the extinction cross section and spectral distribution function of the non-spherical atmospheric charged particles. The quantitative relationship between atmospheric visibility and communication fidelity of satellite-ground quantum link were analyzed then. Simulation results show that the ellipsoid, Chebyshev atmospheric charged particle influences on attenuation of the satellite-ground quantum link increase progressively. When the equivalent particle radius is 0.2 gm and the particle concentration is 50 μg/m^3, the attenuation coefficient and entanglement of the satellite-ground quantum link is 9.21 dB/km, 11.46 dB/km and 0.453, 0.421 respectively; When the atmospheric visibility reduces from 8 km to 2 kin, the communication fidelity of satellite-ground quantum link decreases from 0.52 to 0.08. It is shown that the non-spherical atmospheric charged particles and atmospheric visibility influence greatly on the performance of the satellite-ground quantum link communication system. Therefore, it is necessary to adjust the parameters of the quantum-satellite communication system according to the visibility values of the atmosphere and the shapes of the charged particles in the atmosphere to improve reliability of the satellite-ground quantum link.