4,758 research outputs found
Spectral flow of trimer states of two heavy impurities and one light condensed boson
The spectral flow of three-body (trimer) states consisting of two heavy
(impurity) particles sitting in a condensate of light bosons is considered.
Assuming that the condensate is weakly interaction and that an impurity and a
boson have a zero-range two-body interaction, we use the Born-Oppenheimer
approximation to determine the effective three-body potential. We solve the
resulting Schr\"odinger equation numerically and determine the trimer binding
energies as a function of the coherence length of the light bosonic condensate
particles. The binding energy is found to be suppressed by the presence of the
condensate when the energy scale corresponding to the coherence length becomes
of order the trimer binding energy in the absence of the condensate. We find
that the Efimov scaling property is reflected in the critical values of the
condensate coherence length at which the trimers are pushed into the continuum.Comment: 10 pages including appendices, 4 figures, revised versio
Efimov States of Heavy Impurities in a Bose-Einstein Condensate
We consider the problem of two heavy impurity particles embedded in a gas of
weakly-interacting light mass bosonic particles in the condensed state. Using
the Bogoliubov approach to describe the bosonic gas and the Born-Oppenheimer
approximation for the three-body dynamics, we calculate the modification to the
heavy-heavy two-body potential due to the presence of the condensate. For the
case of resonant interaction between the light bosons and the impurities, we
present (semi)-analytical results for the potential in the limit of a large
condensate coherence length. In particular, we find a formula for the
modification of the Efimov scaling factor due to the presence of a degenerate
bosonic gas background.Comment: 6 pages, 3 figures, final versio
Effective field theory of interactions on the lattice
We consider renormalization of effective field theory interactions by
discretizing the continuum on a tight-binding lattice. After studying the
one-dimensional problem, we address s-wave collisions in three dimensions and
relate the bare lattice coupling constants to the continuum coupling constants.
Our method constitutes a very simple avenue for the systematic renormalization
in effective field theory, and is especially useful as the number of
interaction parameters increases.Comment: 7 pages, 0 figure
Muon capture on nuclei: random phase approximation evaluation versus data for 6 Z 94 nuclei
We use the random phase approximation to systematically describe the total
muon capture rates on all nuclei where they have been measured. We reproduce
the experimental values on these nuclei to better than 15% accuracy using the
free nucleon weak form factors and residual interactions with a mild
dependency. The isospin dependence and the effects associated with shell
closures are fairly well reproduced as well. However, the calculated rates for
the same residual interactions would be significantly lower than the data if
the in-medium quenching of the axial-vector coupling constant is employed to
other than the true Gamow-Teller amplitudes. Our calculation thus suggests that
no quenching is needed in the description of semileptonic weak processes
involving higher multipole transitions and momentum transfer ,
with obvious importance to analogous weak processes.Comment: RevTeX4 10 pages, 2 figures. Revised according to referee report.
Table 1 expanded. Accepted for publication in PR
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