25.07.2013 Views

Ph.D. Thesis - Physics

Ph.D. Thesis - Physics

Ph.D. Thesis - Physics

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

plot(t*J,expsz1)<br />

axis([min(t*J),max(t*J),-2,2]);<br />

ylabel(’ A = 0’);<br />

expsz2 = [init1’*sztot1*init1];<br />

tstep=t(2)-t(1);<br />

curr = init1;<br />

J = 1000;<br />

Jt(1) = J;<br />

Bt(1) = B;<br />

Fr(1) = 0;<br />

for kk = 2:length(t)<br />

Fr(kk) = t(kk)/max(t);<br />

Jt(kk) = Fr(kk)^2*J*(1+A*sin(Omega*t(kk)+pi/2))^(-3);<br />

Bt(kk) = B;<br />

Ht = Jt(kk)*kron(sz,sz)+ B*(kron(eye([2 2]), sx) + kron(sx,eye([2 2])));<br />

curr = expm(-i*Ht*tstep)*curr;<br />

expsz2 = [expsz2, curr’*sztot1*curr];<br />

end<br />

Jm = mean(Jt);<br />

theerr = expsz2-expsz1;<br />

err_result = mean(theerr)<br />

figure(1);<br />

hold on;<br />

subplot(3,1,2);<br />

plot(t*J,expsz2);<br />

axis([min(t*J),max(t*J),-2,2]);<br />

ylabel(’ A = 0.1’);<br />

figure(1);<br />

hold on;<br />

subplot(3,1,3);<br />

plot(t*J,expsz2-expsz1,’r-’);<br />

xlabel(’time (J)’);<br />

ylabel(’Error’);<br />

236

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!