59,070 research outputs found
Spin 1 inversion: a Majorana tensor force for deuteron alpha scattering
We demonstrate, for the first time, successful S-matrix to potential
inversion for spin one projectiles with non-diagonal yielding a
interaction. The method is a generalization of the
iterative-perturbative, IP, method. We present a test case indicating the
degree of uniqueness of the potential. The method is adapted, using established
procedures, into direct observable to potential inversion, fitting ,
, , and for d + alpha scattering over
a range of energies near 10 MeV. The interaction which we find is
very different from that proposed elsewhere, both real and imaginary parts
being very different for odd and even parity channels.Comment: 7 pages Revtex, 4 ps figure
Study of lunar reflective components of solar radio emission semiannual status report
Solar radio frequency reflection from lunar surface for scattering measuremen
Exact and approximate dynamics of the quantum mechanical O(N) model
We study a quantum dynamical system of N, O(N) symmetric, nonlinear
oscillators as a toy model to investigate the systematics of a 1/N expansion.
The closed time path (CTP) formalism melded with an expansion in 1/N is used to
derive time evolution equations valid to order 1/N (next-to-leading order). The
effective potential is also obtained to this order and its properties
areelucidated. In order to compare theoretical predictions against numerical
solutions of the time-dependent Schrodinger equation, we consider two initial
conditions consistent with O(N) symmetry, one of them a quantum roll, the other
a wave packet initially to one side of the potential minimum, whose center has
all coordinates equal. For the case of the quantum roll we map out the domain
of validity of the large-N expansion. We discuss unitarity violation in the 1/N
expansion; a well-known problem faced by moment truncation techniques. The 1/N
results, both static and dynamic, are also compared to those given by the
Hartree variational ansatz at given values of N. We conclude that late-time
behavior, where nonlinear effects are significant, is not well-described by
either approximation.Comment: 16 pages, 12 figrures, revte
The use of Kodak aerochrome infrared color film, type 2443, as a remote sensing tool
An infrared color film, Kodak Aerochrome, type 2443, has replaced the 8443 film. The 2443 has lower contrast than the 8443 film, and allows deeper probing into areas that appear as solid black shadows on the 8443 film. The cyan layer of 2443 is approximately 1 1/2 stops slower, at a density of 1.4, than the yellow and magenta emulsion layers
Strongly-resonant p-wave superfluids
We study theoretically a dilute gas of identical fermions interacting via a
p-wave resonance. We show that, depending on the microscopic physics, there are
two distinct regimes of p-wave resonant superfluids, which we term "weak" and
"strong". Although expected naively to form a BCS-BEC superfluid, a
strongly-resonant p-wave superfluid is in fact unstable towards the formation
of a gas of fermionic triplets. We examine this instability and estimate the
lifetime of the p-wave molecules due to the collisional relaxation into
triplets. We discuss consequences for the experimental achievement of p-wave
superfluids in both weakly- and strongly-resonant regimes
Speed-of-light pulses in the massless nonlinear Dirac equation with a potential
We consider the massless nonlinear Dirac (NLD) equation in dimension
with scalar-scalar self-interaction in the
presence of three external electromagnetic potentials , a potential
barrier, a constant potential, and a potential well. By solving numerically the
NLD equation, we find that, for all three cases, after a short transit time,
the initial pulse breaks into two pulses which are solutions of the massless
linear Dirac equation traveling in opposite directions with the speed of light.
During this splitting the charge and the energy are conserved, whereas the
momentum is conserved when the solutions possess specific symmetries. For the
case of the constant potential, we derive exact analytical solutions of the
massless NLD equation that are also solutions of the massless linearized Dirac
equation.Comment: 11 pages, 7 figure
Investigation of the Coupling Potential by means of S-matrix Inversion
We investigate the inelastic coupling interaction by studying its effect on
the elastic scattering potential as determined by inverting the elastic
scattering -matrix. We first address the effect upon the real and imaginary
elastic potentials of including excited states of the target nucleus. We then
investigate the effect of a recently introduced novel coupling potential which
has been remarkably successful in reproducing the experimental data for the
C+C, C+Mg and O+Si reactions over a
wide range of energies. This coupling potential has the effect of deepening the
real elastic potential in the surface region, thereby explaining a common
feature of many phenomenological potentials. It is suggested that one can
relate this deepening to the super-deformed state of the compound nucleus,
Mg.Comment: 12 pages with 3 figure
Discrete analogue computing with rotor-routers
Rotor-routing is a procedure for routing tokens through a network that can
implement certain kinds of computation. These computations are inherently
asynchronous (the order in which tokens are routed makes no difference) and
distributed (information is spread throughout the system). It is also possible
to efficiently check that a computation has been carried out correctly in less
time than the computation itself required, provided one has a certificate that
can itself be computed by the rotor-router network. Rotor-router networks can
be viewed as both discrete analogues of continuous linear systems and
deterministic analogues of stochastic processes.Comment: To appear in Chaos Special Focus Issue on Intrinsic and Designed
Computatio
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