488 research outputs found
State determination: an iterative algorithm
An iterative algorithm for state determination is presented that uses as
physical input the probability distributions for the eigenvalues of two or more
observables in an unknown state . Starting form an arbitrary state
, a succession of states is obtained that converges to
or to a Pauli partner. This algorithm for state reconstruction is
efficient and robust as is seen in the numerical tests presented and is a
useful tool not only for state determination but also for the study of Pauli
partners. Its main ingredient is the Physical Imposition Operator that changes
any state to have the same physical properties, with respect to an observable,
of another state.Comment: 11 pages 3 figure
On Randomness in Quantum Mechanics
The quantum mechanical probability densities are compared with the
probability densities treated by the theory of random variables. The relevance
of their difference for the interpretation of quantum mechanics is commented
Anisotropic exchange and spin-wave damping in pure and electron-doped SrIrO
The collective magnetic excitations in the spin-orbit Mott insulator
(SrLa)IrO () were investigated by
means of resonant inelastic x-ray scattering. We report significant magnon
energy gaps at both the crystallographic and antiferromagnetic zone centers at
all doping levels, along with a remarkably pronounced momentum-dependent
lifetime broadening. The spin-wave gap is accounted for by a significant
anisotropy in the interactions between isospins, thus
marking the departure of SrIrO from the essentially isotropic
Heisenberg model appropriate for the superconducting cuprates.Comment: 6 pages, 4 figure
Observables have no value: a no-go theorem for position and momentum observables
A very simple illustration of the Bell-Kochen-Specker contradiction is
presented using continuous observables in infinite dimensional Hilbert space.
It is shown that the assumption of the \emph{existence} of putative values for
position and momentum observables for one single particle is incompatible with
quantum mechanics.Comment: 6 pages, 1 Latex figure small corrections, refference and comments
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