Check summation from n=0 to 5 |n><n| in MATLAB?

D=5;

tmpI=eye(D);

ket0=tmpI(:,1); %|0>

ket1=tmpI(:,2); %|1>

ket2=tmpI(:,3); %|2>

ket3=tmpI(:,4); %|3>

ket4=tmpI(:,5); %|4>

ket5=tmpI(:,6); %|5>

% bra is the transpose of ket

bra0=tmpI(1,:); % <0|

bra1=tmpI(2,:); % <1|

bra2=tmpI(3,:); % <2|

bra3=tmpI(4,:); % <3|

bra4=tmpI(5,:); % <4|

Answer 1

[Bjorn Gustavsson]

If |n><n| is the same as <n||n> then you should have a look at the help and documentation to dot. That function will not generalize well to the more general <n|G|n>. For that you might get away with the standard vector-matrix-vector products where you'll have to make some discrete version of the operator G. If |n><n| is not the same as <n||n> you might have to explain what it is supposed to be.

HTH