@mmcdara Thank you so much!

@Axel Vogt Thank you so much!

@acer Thank you with all my heart!!

@Axel Vogt I would like to know what ' ' in Y is doing and " %" in -Usage("%"=) is doing. 

How should I find N (beta, gamma) using your J?

Thank you in advance,

@tomleslie Thank you so much!!

@Axel Vogt Thank you very much!!

@acer Could you help me how to use ArrayInterpolation for the matrix and to use for the contourplot or implicitplot? I am attaching my data for N matrix (51*51)N_data.xlsx

@acer I am trying to reproduce the graph e.1 and e.2) in the paper.  In the equation in the code, alpha = omega*T, gamma(gg)=Delta /T and  beta=d/T. N means negativity. If N greater than 0, it is possible to harvest entanglement (red color in the left figure.) and if N is less than equal to 0, it is not possible to harvest entanglement (the gray color in the left figure.) delta is sigma/T  and Lambda is Lambda*T