916 research outputs found
Accurate Adiabatic Connection Curve Beyond the Physical Interaction Strength
The adiabatic connection curve of density functional theory (DFT) is
accurately calculated beyond the physical interaction strength for Hooke's
atom, two interacting electrons in a harmonic well potential. Extrapolation of
the accurate curve to the infinite coupling limit agrees well with the strictly
correlated electron (SCE) hypothesis but the approach to this limit is more
complex. The interaction strength interpolation is shown to be a good, but not
perfect, fit to the adiabatic curve. Arguments about the locality of
functionals and convexity of the adiabatic connection curve are examined in
this regime.Comment: 7 pages, 5 figure
An enamel-painted glass bottle from a “Turkish pit” in Buda
The fragments of a high quality, enamel painted, blue glass bottle with the date 1671 on its shoulder were found in the Castle District of Buda, in a huge pit dated to the period of the Ottoman occupation. The shape of the object shows eastern influences, while its decoration is clearly western. The origin of the bottle is probably Transylvanian, based on its characteristics and a small group of parallels
Point Estimation of States of Finite Quantum Systems
The estimation of the density matrix of a -level quantum system is studied
when the parametrization is given by the real and imaginary part of the entries
and they are estimated by independent measurements. It is established that the
properties of the estimation procedure depend very much on the invertibility of
the true state. In particular, in case of a pure state the estimation is less
efficient. Moreover, several estimation schemes are compared for the unknown
state of a qubit when one copy is measured at a time. It is shown that the
average mean quadratic error matrix is the smallest if the applied observables
are complementary. The results are illustrated by computer simulations.Comment: 16 pages, 5 figure
Density functional theory in one-dimension for contact-interacting fermions
A density functional theory is developed for fermions in one dimension,
interacting via a delta-function. Such systems provide a natural testing ground
for questions of principle, as the local density approximation should work well
for short-ranged interactions. The exact-exchange contribution to the total
energy is a local functional of the density. A local density approximation for
correlation is obtained using perturbation theory and Bethe-Ansatz results for
the one-dimensional contact-interacting uniform Fermi gas. The ground-state
energies are calculated for two finite systems, the analogs of Helium and of
Hooke's atom. The local approximation is shown to be excellent, as expected.Comment: 10 pages, 7 Figure
Semi-invariants of symmetric quivers of finite type
Let be a symmetric quiver, where is a finite
quiver without oriented cycles and is a contravariant involution on
. The involution allows us to define a nondegenerate bilinear
form on a representation $V$ of $Q$. We shall call the representation
orthogonal if is symmetric and symplectic if is skew-symmetric.
Moreover we can define an action of products of classical groups on the space
of orthogonal representations and on the space of symplectic representations.
For symmetric quivers of finite type, we prove that the rings of
semi-invariants for this action are spanned by the semi-invariants of
determinantal type and, in the case when matrix defining is
skew-symmetric, by the Pfaffians
A educação formando cidadãos : uma experiência das aulas do ProJovem Campo Saberes da Terra
Orientador :Monografia (especialização) - Universidade Federal do Paraná, Setor de ..., Curso de Especialização em ...Inclui referência
- …