منابع مشابه
Pinning of fermionic occupation numbers.
The Pauli exclusion principle is a constraint on the natural occupation numbers of fermionic states. It has been suspected since at least the 1970s, and only proved very recently, that there is a multitude of further constraints on these numbers, generalizing the Pauli principle. Here, we provide the first analytic analysis of the physical relevance of these constraints. We compute the natural ...
متن کاملOccupation numbers in Self Consistent RPA
A method is proposed which allows to calculate within the SCRPA theory the occupation numbers via the single particle Green function. This scheme complies with the Hugenholtz van Hove theorem. In an application to the Lipkin model it is found that this prescription gives consistently better results than two other commonly used approximations: lowest order boson expansion and the number operator...
متن کاملWhen are observable states necessary?
In order to use commercial off-the-shelf (COTS) products, the engineer must be able to prove that the COTS product is equivalent to the specified design. In most cases, this requires observable states, which are usually not available, because the supplier may not know or may not want to disclose the internal states of the system. This paper first presents the following reasons for proving syste...
متن کاملNumbers Are Just Numbers
Making good choices about retirement involves the processing of numbers. In particular, consumers must have easily available, accurate, and timely numbers, and they must also use them. Contrary to the consumer-driven approach, however, the evidence demonstrates that having an abundance of information does not always translate into it being used to inform choices. The challenge is not merely to ...
متن کاملNatural occupation numbers in two-electron quantum rings.
Natural orbitals (NOs) are central constituents for evaluating correlation energies through efficient approximations. Here, we report the closed-form expression of the NOs of two-electron quantum rings, which are prototypical finite-extension systems and new starting points for the development of exchange-correlation functionals in density functional theory. We also show that the natural occupa...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Physics Letters B
سال: 2002
ISSN: 0370-2693
DOI: 10.1016/s0370-2693(01)01504-0