Producing entanglement
Modern theoretical physics of condensed matter is sufficiently developed to compute all physical quantities of interest. Perhaps this signals that we shall proceed to the next challenge, and compute unphysical ones.
Most interesting unphysical quantities are related to information, especially quantum aspects of it. They characterize things like entanglement of quantum states and their informational content. The "unphysical" aspect is that these quantities are not linear in density matrix, and therefore can not be regarded as common quantum observables. Non-linearity makes the computation of these quantities rather challenging from the technical point of view.
There is a flourishing community dealing with these quantities in condensed matter. I am not exactly a part of it, but these things interest me, and I’d like to be. I have decided to attend their workshop in Dresden in June.
For this workshop, I’d like to make a small exercise, so to say, to produce some entanglement by myself. I’ve got an interesting starting idea, and elaborated on this. Naturally, I’d like to compare my findings with the results of previous research. In particular, I wanted to undrestand the correspondence with poineering results of Carlo Beenakker and Leonid Levitov.
Well, it turned out that the gentlemen have produced entanglement of a different sort, that I failed to understand from the beginning. This is the danger to work with unphysical values: they are subjective so small differences in interpretation and taste generate great differences in final answers. So I have to learn more and understand more. The exercise took most part of the week past.
