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I have been reading tong's lectures notes, as well as Prange / Girvin book and Laughlin nobel's lecture. I still can't figure it out.

What is the laughlin ground state off ? I understand there are neutral excitations that are either bound qp-qh pairs or unbound qp-qh pairs (is that correct) ? The bound one giving the magneto-roton ?

What about the charged excitations ? They change the density, does that mean they aren't excited states ? If they are, why don't we ever have a energy spectrum showin them as excited states ?

Is it possible to excited as 1/m state to a 1/m-2 state ? For instance to excite the 1/3 state to a 1 state ?

For instance here (p57,58), they talk about 1 quasi electron state aournd 1/3 filling fraction as a ground state (though I noted the energy mentionned seems to be higher than the 1/3 state. Does that mean that the 1/3 state is the ground state of any small density variation ? How small, as lowering to much the density should leat to a 1 state ?)

This topic didn't help as it's going in the other direction, stating that excitation aren't excited states.

Lou
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From more reasearch, it seems that this is the answer :

http://guava.physics.uiuc.edu/~nigel/courses/569/Essays_Fall2006/files/Zhang.pdf (end of p11)

So the filling factor does stay the same up to when the magnetic field is strong enough to lead to the next filling factor. So that the quasi particles states would be excited states ! What I still don't get is why I can't find any energy spectrum analysis explaining what states are from quasiholes (I only find collective excitations spectrum ? Or what I understand as such)

Lou
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