How can write Dirac bra-ket notation in MATLAB? Example please.

Bra-ket notation is | > , <|

[Jan]

Where do you want to "write" this? Inside code, in the command window, as annotation or label in a diagram, on a button of a GUI?

[Image Analyst]

@Idrees Muhammad You accepted the answer below so we assume you figured it out and got it working. 🙂 Thanks for accepting and awarding @Bjorn Gustavsson "reputation points".

[Idrees Muhammad]

Sir, you also can help me.

Answer 1

[Bjorn Gustavsson]

That depends on what you want to apply the bra-ket on. If it is simple vectors you might get away with simple inner-products using dot. If you have some more advanced objects (wave-functions, and some quantum-mechanical operator) you might start with something like:

function Q = bra_ket(Psi,Phi,f_op)
Q = integral3(@(r1,r2,r3) Psi(r1,r2,r3).*f_op(Phi(r1,r2,r3)),r1min,r1max,r2min,r2max,r3min,r3max)
end

(There should surely be a conjugation in there somewhere). This might run into problems when you need to calculate gradients for the operator acting on Phi for example, the function should be in the integral3-call should be capable to handle vectorized input and that might require some ingenuity.

If you have wave-functions on some finite grid you might get something starting with trapz:

function Q = bra_ket_traps(Psi,Phi,f_op,r1,r2,r3)
opPhi = f_op(Phi,r1,r2,r3); % Here you might need additional argument
Q = trapz(r3(1,1,:),trapz(r2(1,:,1),trapz(r1(:,:,1),conj(Psi).*(opPhi)),2),3);
end

You might also have some good use of the chebfun-toolbox for more clever tools. You can find it on the file exchange.

HTH

[Jan]

@Idrees Muhammad: Accepting an answer is a signal, that the problem is solved.

What have you tried so far and what is the actual problem? "Do not get" does not explain this.

[Bjorn Gustavsson]

@Idrees Muhammad, the way you ask makes me suspect that you are very new to matlab. If that's the case you might get off to a faster start by spending a couple of hours on the on-ramp course/information/material, which is designed to get people up to speed as fast as possible. You can browse through the parts that you think are most relevant for your current problem.

HTH

[Idrees Muhammad]

Thank you very much 🌹

[Idrees Muhammad]

Hello , whenever i run these funtion its not worked,please help me and put some values to run.i try much more but not get the idea.

function Q = bra_ket(Psi,Phi,f_op)

Q = integral3(@(r1,r2,r3) Psi(r1,r2,r3).*f_op(Phi(r1,r2,r3)),r1min,r1max,r2min,r2max,r3min,r3max)

end

function Q = bra_ket_traps(Psi,Phi,f_op,r1,r2,r3)

opPhi = f_op(Phi,r1,r2,r3); % Here you might need additional argument

Q = trapz(r3(1,1,:),trapz(r2(1,:,1),trapz(r1(:,:,1),conj(Psi).*(opPhi)),2),3);

end

[Bjorn Gustavsson]

What are yout Psi, Phi? Wavefunctions defined in what way? What dimensionality are your problem? What is the operator f_op? Does f_op work on Phi and Psi in the way you intend?