Recent content by Thor90

Sorry for the mistake I know that, the fact is that is my first time doing this kind of things and I have no idea how to use/install lapack, but if it's the only way I will try to do that. I have already done my search but as I said before I am not an expert and I am not able to...

There is nothing that doesn't work with my program. I am simply not understanding how to decompose a matrix this way in C (I am a physics not a computer scientist), that means in an iterative way. Where can I find an algorithm to decompose a matrix like this? How does the Hessemberg form come in...

Hi, I am trying to solve the problem of finding eigenvalus for a general square symmetric matrix with the QR algorithm. I have understood that this task is much easier if the matrix is in an Hessemberg form, so I have implemented a function that does that with the Housholder method, but I can't...

Ok you were right, one of the eigenvectors is (0,-1,1,0), as you were about the ##S^2## operator; what I still do not understand is why my singlet of 0 spin is the first excited state and not the ground state, as it usually is, since the energy eigenvalue of ##(2\lambda - \sqrt{4\lambda^2...

You are absolutely right, the fact is I have found them with wolfram alpha so I thought they were good..I think I will try do the calculations again. so basically I have to evalute the product ##\sum_\alpha \sigma_0^\alpha \sigma1^\alpha## since ##\sigma^2=1##? Anyway thank you for your help...

Well there are theories in which the possible distances are quantized (I do not mean the energy levels of a particle in a given potential, I am saying theories in which you have a grid in the space time), maybe you are referring to validated teories? I think there is no special reason why you...

You mean total spin along the z-axis, which operator form should be simply ##\sigma_0^z + \sigma_1^z##, am I right? I have already done it, but I am not understanding why my states should have a definite spin polarization, since the ##H_\lambda## interaction Hamiltonian does not commute with the...

In quantum mechanics a quantum number is "label" to address an eigenvalue of some conserved quantity (that in QM formalism is an operator that commutes with the hamiltonian), and the principale ones, for the classic problem of an electon that orbits around a nucleous, are the eigenvalues of the...

Homework Statement I am trying to solve the model analitically just for 2 sites to have a comparison between computational results. The problem is my professor keeps saying that the result should be a singlet ground state and a triplet of excited states, but when I compute it explicitally I...

Hi everyone, I am a master student in theoretical physics, doing my thesis in TN methods applied to solid state physics. Hello to everyone.