Talk:Quantum dissipation

In the line that defines the specral function $$J(\omega)$$ it would be very useful to explain what the spectral function is, eg. how is it determined from the Hamiltonian?

Javi.Sabio: I have removed the "the DLD model" section. Although this model is of course one of the many applications of the general theory of Quantum Dissipation, I think that it is by far not as relevant to the field as the other models commented, and it should not be presented as a central result of the theory, since it is misleading for those who want to get a quick view of this field. Since this is an introductory article to Quantum Dissipation, it makes no sense to refer to the many models that have applied this theory to a variety of systems and situations, enlightening us with new interesting phenomena, but not at the level of the seminal articles of Caldeira and Leggett. Wikipedia is not a place to reproduce the large academic literature that already exists, but a place to refer to the most general and important results, and provide the reader with a few references to continue, if interested, exploring the field. Particular authors should not use Wikipedia to spread their own scientific work. — Preceding unsigned comment added by Javi.sabio (talk • contribs) 21:46, 10 January 2011 (UTC)

Note
This article is quite poor as an introduction, and in particular it was missing a "see also" section. My suggestion is to have links to wiki pages on the various available models in the literature. I have added some entries that should be prepared by someone in the future. For example models for dissipation of a "particle in a ring" are conceptually important and have no been covered. RMT modelling is also an important arena. Doroncohen —Preceding undated comment added 03:59, 14 July 2011 (UTC).

Javi.sabio I agree that the article can be improved in contents, and I strongly encourage experts in the field to expand it in order to detail mentioned topics and add new topics missing. A section giving a summary of experimental realizations might be interesting, for instance, but trying to refer only the main references in the literature and the most striking results. I emphasize again that Wikipedia should not be used to advertise one own's scientific work, if there is not a good consensus in the scientific community that the contribution is really fundamental. —Preceding undated comment added 15:08, 4 August 2011 (UTC).

Article states wrong facts about Hamilton formalism and thus wrong motivation for the two models!
The Hamilton formalism is able to include energy dissipation by considering time dependent Hamiltonians! Thus the motivation for the two models describing quantum dissipation is wrong in the section:

"The main problem to address dissipation at the quantum level is the way to envisage the mechanism of irreversible loss of energy. Quantum mechanics usually deal with the Hamiltonian formalism, where the total energy of the system is a conserved quantity. So in principle it would not be possible to describe dissipation in this framework."

In my opinion the "only" thing the Hamilton formalism (thus a unitary time evolution) can not include is dephasing, thus some kind of "information dissipation". The question for this article is: What is the best definition for quantum dissipation? Is it more like "energy dissipation" or more like "dephasing". Looking at the first section of this article or other Wikipedia pages, it should be more like "energy dissipation". See page on "Open quantum systems", where they state: "Loss of energy to the environment is termed quantum dissipation, while loss of coherence is termed quantum decoherence.". If we follow this definition, the motivation with the Hamiltonian formalism should be deleted completely. I have found this wrong statement in many circumstances, thus we should maybe write an additional section about "Energy dissipation in Hamiltonian formalism/unitary time evolution" here!!

Also see: https://physics.stackexchange.com/questions/500198/energy-dissipation-in-unitary-dynamics — Preceding unsigned comment added by Matthiashowiki (talk • contribs) 09:58, 5 September 2019 (UTC)