68 research outputs found
Kaonic deuterium and low-energy antikaon-nucleon interaction
A new evaluation of the level shift and width of kaonic deuterium is
presented based on an accurate three-body calculation, using as
input a realistic antikaon-nucleon interaction constrained by the SIDDHARTA
kaonic hydrogen data. The three-body Schr\"odinger equation is solved with a
superposition of a large number of correlated Gaussian basis functions
extending over distance scales up to several hundred fm. The resulting energy
shift and width of the kaonic deuterium level are keV and
keV, with estimated uncertainties at the 10% level.Comment: 9 pages, 2 figures, based on the talk presented at the EXA2017
conferenc
Short-range correlations in nuclei with similarity renormalization group transformations
Realistic nucleon-nucleon interactions induce
short-range correlations in nuclei. To solve the many-body problem unitary
transformations like the similarity renormalization group (SRG) are often used
to soften the interactions.
Two-body densities can be used to illustrate how the SRG
eliminates short-range correlations in the wave function. The short-range
information can however be recovered by transforming the density operators.
The many-body problem is solved for He in the no core
shell model (NCSM) with SRG transformed AV8' and chiral N3LO interactions. The
NCSM wave functions are used to calculate two-body densities with bare and SRG
transformed density operators in two-body approximation.
The two-body momentum distributions for AV8' and N3LO
have similar high-momentum components up to relative momenta of about
, dominated by tensor correlations, but differ in their
behavior at higher relative momenta. The contributions of many-body
correlations are small for pairs with vanishing pair momentum but not
negligible for the momentum distributions integrated over all pair momenta.
Many-body correlations are induced by the strong tensor force and lead to a
reshuffling of pairs between different spin-isospin channels.
When using the SRG it is essential to use transformed
operators for observables sensitive to short-range physics. Back-to-back pairs
with vanishing pair momentum are the best tool to study short-range
correlations.Comment: 13 pages, 9 figures, submitted to Phys. Rev.
Studying short-range correlations and momentum distributions with unitarily transformed operators
Short-range correlations in 4He are investigated using many-body wave
functions obtained in the no-core shell model. The similarity renormalization
group (SRG) is used to evolve the Argonne V8' interaction and the density
operators. The effects of short-range correlations are reflected in the
two-body densities in coordinate space as a function of the distance between
two nucleons, or alternatively in in momentum space as function of the relative
momentum between two nucleons. The SRG transformation is performed in two-body
approximation. The importance of missing three-body and higher-body
contributions is investigated by comparing results obtained for different flow
parameters and by comparing to exact results with the bare Argonne V8'
interaction obtained in the correlated Gaussian approach.Comment: 4 pages, 2 figures, Proc. 2nd Conference on "Advances in Radioactive
Isotope Science" (ARIS2014) June 1-6, 2014, Tokyo, Japan, to be published in
JPS Conference Proceeding
Towards an ab initio description of the light-nuclei radiative captures
The and astrophysical factors are evaluated at low
collision energies (less than 2.5 MeV in the centre-of-mass frame) within the
no-core shell model with continuum approach using a renormalized chiral
nucleon-nucleon interaction.Comment: 4 pages, submitted as a proceeding of the 21st International
Conference on Few-Body Problems in Physic
Quasiparticle properties of a single alpha particle in cold neutron matter
Light clusters such as alpha particles and deuterons are predicted to occur
in hot nuclear matter as encountered in intermediate-energy heavy-ion
collisions and protoneutron stars. To examine the in-medium properties of such
light clusters, we consider a much simplified system in which like an impurity,
a single alpha particle is embedded in a zero-temperature, dilute gas of
non-interacting neutrons. By adopting a non-selfconsistent ladder approximation
for the effective interaction between the impurity and the gas, which is often
used for analyses of Fermi polarons in a gas of ultracold atoms, we calculate
the quasiparticle properties of the impurity, i.e., the energy shift, effective
mass, quasiparticle residue, and damping rate.Comment: 19 pages, 3 figures, version accepted for PRC: discussions on p-wave
contributions and the validity range of the model were adde
and astrophysical factors from the no-core shell model with continuum
The and astrophysical factors are calculated within
the no-core shell model with continuum using a renormalized chiral
nucleon-nucleon interaction. The
astrophysical factors agree reasonably well with the experimental data
while the ones are overestimated. The
seven-nucleon bound and resonance states and the elastic scattering are also studied and compared with experiment. The
low-lying resonance properties are rather well reproduced by our approach. At
low energies, the -wave phase shift, which is non-resonant, is
overestimated.Comment: 8 pages, submitted to Phys. Lett.
Intersections of ultracold atomic polarons and nuclear clusters: How is a chart of nuclides modified in dilute neutron matter?
Neutron star observations, as well as experiments on neutron-rich nuclei,
used to motivate one to look at degenerate nuclear matter from its extreme,
namely, pure neutron matter. As an important next step, impurities and clusters
in dilute neutron matter have attracted special attention. In this paper, we
review in-medium properties of these objects on the basis of the physics of
polarons, which have been recently realized in ultracold atomic experiments. We
discuss how such atomic and nuclear systems are related to each other in terms
of polarons. In addition to the interdisciplinary understanding of in-medium
nuclear clusters, it is shown that the quasiparticle energy of a single proton
in neutron matter is associated with the symmetry energy, implying a novel
route toward the nuclear equation of state from the neutron-rich side.Comment: 28 pages, 2 figure
Theory and application of explicitly correlated Gaussians
The variational method complemented with the use of explicitly correlated Gaussian basis functions
is one of the most powerful approaches currently used for calculating the properties of few-body
systems. Despite its conceptual simplicity, the method offers great flexibility, high accuracy, and can
be used to study diverse quantum systems, ranging from small atoms and molecules to light nuclei,
hadrons, quantum dots, and Efimov systems. The basic theoretical foundations are discussed, recent
advances in the applications of explicitly correlated Gaussians in physics and chemistry are
reviewed, and the strengths and weaknesses of the explicitly correlated Gaussians approach are
compared with other few-body technique
- …