Sonia Bacca
TRIUMF
bacca@triumf.ca
Brett Esry
Kansas State University
esry@phys.ksu.edu
Lucas Platter
University of Washington
lplatter@phys.washington.edu
Program Coordinator:
Laura Lee
lee@phys.washington.edu
(206) 685-3509
Application form
March 8 - 12, 2010
The goal of this workshop is to explore the connections between
different theoretical methods used to model weakly bound few-body
systems.
Nature shows the existence of weakly bound systems in different sectors,
ranging from the atomic to the nuclear physics regime. We bring together
practitioners from the nuclear physics and the AMO (atomic, molecular and optical)
community to cross fertilize these fields.
Few-body systems with large scattering length exhibit
universal features (universality), which are independent of the details
of the interaction, and thus are common to nuclear and AMO systems.
In nuclear physics large scattering lengths are found in weakly bound
systems like halo nuclei, which serve as nuclear examples of
universality. Few-nucleon systems are another exmaple by themselves,
since the two-nucleon scattering length is much larger than the range
of the nucleon-nucleon interaction. Exact methods used to study
few-nucleon systems are valuable to investigate weakly bound nuclei
(halo and resonant states) either by an extension of ab-initio
calculations towards larger mass number, or via the use of cluster
models, where the core becomes a constituent of the nucleus. In
atomic physics, experiments with ultra-cold atoms allow the tuning of
the atomic two-body scattering length with an external magnetic field
to arbitrary values and in particular to significantly larger values
than the range of the atom-atom interaction. Recent experimental
efforts have demonstrated that the implications of three- and
four-body universality can be observed and are relevant for resonantly
interacting Bose gases and Fermi gases with more than two spin states.
The common interest of the nuclear and atomic physics
community in large scattering length systems is the driver for the workshop.
To stimulate progress and crossfertilization, we envision focusing on the following topics:
Ab-initio Methods in Nuclei and AMO Systems
Very different ab-initio approaches are used to
calculate the properties of few-body systems, ranging from Faddeev methods
to diagonalization methods that rely on an expansion of the wave functions
in a complete basis set, like e.g. hyper-spherical harmonics and no core
shell model. This workshop would provide an excellent opportunity to
identify the advantages and disadvantages of the approaches employed by
different groups.
The properties of halo systems such as
6He are very often calculated by assuming that the core of the halo can
be considered as a constituent and an effective potential is used to
parameterize the interaction between core and halo nucleons. Ab-initio wave
functions methods capable of calculating the nucleon-core scattering
properties can therefore provide important input to improve the quality of
these effective interactions.
Identification of Key Observables to Study
Weakly bound systems have attracted increasing attention in the theory
community, triggered by recent advances in experimental measurements.
An important goal we want to achieve with this
workshop is an identification of observables that are required to be
considered in the immediate future. First, we want to understand what
different theoretical approaches can deliver. Second, we aim at determining
which observable can be measured with the required accuracy.
The following questions will be addressed during the workshop: What
can we learn from neutron-rich nuclei about three-body forces? What
are the limits of Efimov universality? How are universal features
modified by the finite range of the underlying interaction? What are
these universal features in systems of distinguishable particles with
different masses? What are the universal features of the 5-body
system? Can experiments with ultracold atoms, where the P-wave
interaction can be tuned, provide insight into the physics of the
neutron drip line?
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