2,544 research outputs found
Tracking interacting dust: comparison of tracking and state estimation techniques for dusty plasmas
When tracking a target particle that is interacting with nearest neighbors in
a known way, positional data of the neighbors can be used to improve the state
estimate. Effects of the accuracy of such positional data on the target track
accuracy are investigated in this paper, in the context of dusty plasmas. In
kinematic simulations, notable improvement in the target track accuracy was
found when including all nearest neighbors in the state estimation filter and
tracking algorithm, whereas the track accuracy was not significantly improved
by higher-accuracy measurement techniques. The state estimation algorithm,
involving an extended Kalman filter, was shown to either remove or
significantly reduce errors due to "pixel locking". It is concluded that the
significant extra complexity and computational expense to achieve these
relatively small improvements are likely to be unwarranted for many situations.
For the purposes of determining the precise particle locations, it is concluded
that the simplified state estimation algorithm can be a viable alternative to
using more computationally-intensive measurement techniques.Comment: 11 pages, 6 figures, Conference paper: Signal and Data Processing of
Small Targets 2010 (SPIE
SUSY transformation of the Green function and a trace formula
An integral relation is established between the Green functions corresponding
to two Hamiltonians which are supersymmetric (SUSY) partners and in general may
possess both discrete and continuous spectra. It is shown that when the
continuous spectrum is present the trace of the difference of the Green
functions for SUSY partners is a finite quantity which may or may not be equal
to zero despite the divergence of the traces of each Green function. Our
findings are illustrated by using the free particle example considered both on
the whole real line and on a half line
Ideal gas behavior of a strongly-coupled complex (dusty) plasma
In a laboratory, a two-dimensional complex (dusty) plasma consists of a
low-density ionized gas containing a confined suspension of Yukawa-coupled
plastic microspheres. For an initial crystal-like form, we report ideal gas
behavior in this strongly-coupled system during shock-wave experiments. This
evidence supports the use of the ideal gas law as the equation of state for
soft crystals such as those formed by dusty plasmas.Comment: 5 pages, 5 figures, 5 authors, published versio
Exact propagators for SUSY partners
Pairs of SUSY partner Hamiltonians are studied which are interrelated by
usual (linear) or polynomial supersymmetry. Assuming the model of one of the
Hamiltonians as exactly solvable with known propagator, expressions for
propagators of partner models are derived. The corresponding general results
are applied to "a particle in a box", the Harmonic oscillator and a free
particle (i.e. to transparent potentials).Comment: 31 page
Eigenphase preserving two-channel SUSY transformations
We propose a new kind of supersymmetric (SUSY) transformation in the case of
the two-channel scattering problem with equal thresholds, for partial waves of
the same parity. This two-fold transformation is based on two imaginary
factorization energies with opposite signs and with mutually conjugated
factorization solutions. We call it an eigenphase preserving SUSY
transformation as it relates two Hamiltonians, the scattering matrices of which
have identical eigenphase shifts. In contrast to known phase-equivalent
transformations, the mixing parameter is modified by the eigenphase preserving
transformation.Comment: 16 pages, 1 figur
Interactions of Hermitian and non-Hermitian Hamiltonians
The coupling of non-Hermitian PT-symmetric Hamiltonians to standard Hermitian
Hamiltonians, each of which individually has a real energy spectrum, is
explored by means of a number of soluble models. It is found that in all cases
the energy remains real for small values of the coupling constant, but becomes
complex if the coupling becomes stronger than some critical value. For a
quadratic non-Hermitian PT-symmetric Hamiltonian coupled to an arbitrary real
Hermitian PT-symmetric Hamiltonian, the reality of the ground-state energy for
small enough coupling constant is established up to second order in
perturbation theory.Comment: 9 pages, 0 figure
Darboux transformations of coherent states of the time-dependent singular oscillator
Darboux transformation of both Barut-Girardello and Perelomov coherent states
for the time-dependent singular oscillator is studied. In both cases the
measure that realizes the resolution of the identity operator in terms of
coherent states is found and corresponding holomorphic representation is
constructed. For the particular case of a free particle moving with a fixed
value of the angular momentum equal to two it is shown that Barut-Giriardello
coherent states are more localized at the initial time moment while the
Perelomov coherent states are more stable with respect to time evolution. It is
also illustrated that Darboux transformation may keep unchanged this different
time behavior.Comment: 13 page
Phase shift effective range expansion from supersymmetric quantum mechanics
Supersymmetric or Darboux transformations are used to construct local phase
equivalent deep and shallow potentials for partial waves. We
associate the value of the orbital angular momentum with the asymptotic form of
the potential at infinity which allows us to introduce adequate long-distance
transformations. The approach is shown to be effective in getting the correct
phase shift effective range expansion. Applications are considered for the
and partial waves of the neutron-proton scattering.Comment: 6 pages, 3 figures, Revtex4, version to be publised in Physical
Review
Entangled Quantum State Discrimination using Pseudo-Hermitian System
We demonstrate how to discriminate two non-orthogonal, entangled quantum
state which are slightly different from each other by using pseudo-Hermitian
system. The positive definite metric operator which makes the pseudo-Hermitian
systems fully consistent quantum theory is used for such a state
discrimination. We further show that non-orthogonal states can evolve through a
suitably constructed pseudo-Hermitian Hamiltonian to orthogonal states. Such
evolution ceases at exceptional points of the pseudo-Hermitian system.Comment: Latex, 9 pages, 1 figur
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