i want to know what is physical idea behind "correlation function"
as you know in quantum we define <B(t)B(s)> , B(t) and B(s) are operators in different time. and angular bracket shows averaging.
is this definition say that if correlation function does not vanish then the observables...
suppose i run Two notebook and in each of them i have matrix A and Constant B and a function C
in each notebook these things have the same name.
if in notebook 1 i assign B=10 then in notebook 2 B is 10 too , which is not my desire.
how can i define these constants and matrices and...
Bill Simpson thanks for your comments.
jackmell i do not know how to do that.
however i think i should define the results of computation in new variables.
for example if after a computation i obtain a matrix i define it for another variable.
when i run a heavy computation on mathematica in the same time even if i want to calculate 2+2 , mathematica does not calculate it until calculating of heavy computation finishes.
another problem is that when i do a heavy computation and obtain results , after closing mathematica...
i want to sum over two indices i and j . the elemet that i must sum is (x^(i,j))-i
that is x has superscript i,j and subscript i.
but in mathematica it gives me error.
here is the notebook :
i solve numerically two coupled equation and obtain two function x[t] and y[t].
how i plot x[t] versus y[t] so that horizontal axis to be x[t] and vertical axis to be y[t].
here is the notebook of mathematica
in this article that explain the method of peani baker
i can not understand how in page 5 for first example it calculate element (1,2) of I(t)(with subscript n)
can anybody help?