Prof.
Tobias Frederico
(Instituto Tecnologico de Aeronautica)
10/10/2011 09:20
The rich nature of quantum few-body systems interacting with
short-ranged forces is not shaped only by three-body properties.
Weakly-bound tetramers composed by identical bosons and their
excited states have a characteristic scale, which is independent of
the trimer one, for resonant pairwise interaction in the unitary
limit (zero two-body binding or infinite scattering length....
Prof.
Masahito Ueda
(University of Tokyo)
10/10/2011 10:00
Abstract: Recent theoretical and experimental efforts to create and understand the Efimov states in a three-component mixture of 6Li are reviewed [1,2]. It is pointed out that the recently observed loss peaks at 602G and 685G [3,4], which are the crossing points of the atom-dimer threshold and the ground and first excited Efimov states, show significant deviations from the universal Efimov...
Dr
Arnoldas Deltuva
(Centro Fisica Nuclear, U. Lisboa)
10/10/2011 11:00
Few-particle systems with resonant interactions, i.e., large
two-particle scattering length, possess a number of universal properties and correlations between observables. We focus on the four-boson system,
in particular, on the two tetramer states associated with each
Efimov trimer. However, only the two lowest tetramers
are true bound states; all higher tetramers lie above the...
Prof.
Brett Esry
(Department of Physics and J.R. Macdonald Laboratory Kansas State University)
10/10/2011 11:40
Few-body physics has seen a few rather dramatic experimental realizations
of long-predicted Efimov physics in the last five years. These successes
have come thanks to the unprecedented control that ultracold atomic gases afford
for few-body systems. I will describe a new class of few-body states that might
also be observable in ultracold systems. These states occur not for short-range...
Mme
Marco Giulio Giammarchi
((on behalf of the AEGIS Collaboration) Istituto Nazionale di Fisica Nucleare, via Celoria 16, 20133 Milano, Italy)
10/10/2011 15:00
AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is an experiment at the CERN Antiproton Decelerator to study antimatter. The main goal of the AEGIS experimental programme is the test of fundamental laws such as the Weak Equilvalence Principle (WEP) and CPT symmetry. In the first phase of AEGIS, a beam of antihydrogen will be formed whose fall in the gravitational field will...
Anna Okopinska
(Jan Kochanowski University)
10/10/2011 15:40
We study systems composed of up to four charged bosons within strongly anisotropic traps. A detailed examination of the correlation properties is carried out within the framework of the single-mode approximation of the transverse component. The correlation entropy of the quasi-one dimensional systems is discussed in dependence on the confinement anisotropy and the interaction strength. A...
Dr
Ludovic pricoupenko
(LPTMC - Université Pierre et Marie Curie (Paris 6))
10/10/2011 16:40
Ultra-cold atoms permit to explore few-body systems in regimes where two-body scattering is resonant. The zero-range approximation of the pairwise interaction is especially adapted to the so-called unitary regime, while for a large but finite scattering length or also in p wave resonances, more detailed approaches are needed for describing few-body systems. In this talk, we show the interest...
M.
Peder Sørensen
(Institute of Physics and Astronomu, University of Aarhus)
10/10/2011 17:20
The zero-range model subjects free solutions to the Schrödinger equation to the Bethe-
Peierls boundary condition at zero separation as a way of implementing the scattering length.
The range of the potential can be incorporated by using the effective range expansion in the
boundary condition [1]. This removes the problematic Thomas collapse yet the Efimov effect
remains. Alternatively, a...
Prof.
Nils Elander
(AlbaNova Univ. Ctr., Stockholm University, Sweden)
10/10/2011 18:00
In my talk will describe how resonance trajectories appear and how they are bounded on the complex energy plane. I will then introduce the mathematical spectral function and the spectral density. From there I will describe how the spectral density can be partitioned into contributions from uncovered resonances and the free particle spectral density. I will then turn to scattering cross section...
Dr
Servaas Kokkelmans
(Eindhoven University of Technology)
11/10/2011 09:00
We observed the existence of a universal regime for Efimov trimers
through three-body recombination loss in the vicinity of a Feshbach
resonance, for ultracold Li-7 atoms. The reported results crucially
depend on a careful mapping of the scattering length on the magnetic
field. We characterize two broad Feshbach resonances in different spin
states via the binding energies of weakly bound...
Prof.
Sadhan Adhikari
(São Paulo State University, Institute of Theoretical Physics)
11/10/2011 09:40
We study the formation and dynamics of bright, vortex-bright, and
gap solitons in a dipolar Bose-Einstein condensate (BEC). The
bright and vortex-bright solitons are considered in a cigar-shaped
dipolar BEC for large repulsive atomic interactions, while no
solitons can appear in a BEC of atoms without dipolar moment.
Phase diagram showing the region of stability of these solitons...
Jose P. D'Incao
(JILA, University of Colorado and NIST)
11/10/2011 10:40
In the past few years experimental and theoretical advances in the understanding
of few-body physics in ultracold quantum gases with tunable interactions have
lead to the confirmation of one of the most fundamental quantum phenomena
involving just a few particles: The Efimov effect. In our recent work, we have
extended our adiabatic hyperspherical representation to incorporate the effects...
Prof.
L. U. Ancarani
(U. Metz, France)
11/10/2011 11:20
We study some formal aspects of the exterior complex scaling (ECS) method when imple-
mented for both short and long{range two{body potentials. We raise some questions, provide some answers, and propose a distorted-wave reformulation within a ECS approach. Particular attention is put on the applicability of the method to the pure two-body Coulomb potential. Complex scaling has been for a long...
Dr
Jeremy Armstrong
(Aarhus)
11/10/2011 15:00
We consider the N -body problem in a layered geometry containing cold polar molecules with
dipole moments that are polarized perpendicular to the layers. A harmonic approximation is
used to simplify the Hamiltonian and bound state properties of the two-body inter-layer dipolar
potential are used to adjust this effective interaction. To model the intra-layer repulsion of the
polar molecules,...
Dr
Jonas Cremon
(Lund University)
11/10/2011 15:40
We study the few-body physics of trapped atoms or molecules with electric or magnetic dipole moments aligned by an external field. Using exact numerical diagonalization appropriate for the strongly correlated regime, as well as a classical analysis, we show how Wigner localization emerges with increasing coupling strength. The Wigner states exhibit non-trivial geometries due to the anisotropy...
Prof.
Luca Salasnich
(Department of Physics, University of Padova)
11/10/2011 16:40
The unitary Fermi gas made of dilute and ultracold atoms with an infinite s-wave inter-atomic scattering length is discussed. First we introduce an efficient Thomas-Fermi-von Weizsacker density functional which describes accurately the density profile of the unitary Fermi gas trapped by an external potential. Then, the collective frequencies of monopole, quadrupole and octupole oscillations...
Aksel Jensen
(Aarhus University),
Artem Volosniev
(Aarhus University),
Dmitri Fedorov
(Aarhus University),
Nikolaj Zinner
(Aarhus University)
11/10/2011 17:20
We investigate two, three and four polarized cold dipolar molecules in layered
structures [1]. We first study the two-body
problem with anisotropic potential. We found numerically that
the two particles always form a bound state. We shall give analytical
expressions for energies and wave functions in the weak coupling limit
where universality or model independence are approached, and...
Dr
jimmy rotureau
(Chalmers University)
11/10/2011 18:00
Systems with large scattering length $a_2$ are of particular interest since they exhibit universal properties when particle momenta are small compared to $1/r_0$ with $r_0$ being the range of the interaction. This situation occurs for instance, in nuclear physics where the two-nucleon system has two S-wave channels where $a_2 >>r_0$. Using the principles of the pionless Effective Field Theory...
Prof.
Emiko Hiyama
(RIKEN? Japan)
12/10/2011 09:00
One of the primary goals in hypernuclear physics is to extract information about baryon-baryon interactions in a unified way. By making use of the hyperon(Y)-nucleon(N) scattering data and the rich NN data complementarity, several types of the YN/YY interaction models have been proposed on the basis of the SU(3) and SU(6) symmetries. However, these YN/YY interaction models have a great deal of...
Dr
Elena Santopinto
(INFN)
12/10/2011 09:40
The formalism for a new generation of Constituent Quark Models, in which the higher Fock components of the baryon wave functions are explicitly and systematically introduced through a QCD inspired 3P0 pair-creation mechanism, has been recently constructed [1]. This unquenching of the Quark Model will be presented discussed. It will be shown how after renormalization, the unquenching [1]...
Dr
Giovanni Salme'
(Istituto Nazionale di Fisica Nucleare)
12/10/2011 10:40
Within a fully covariant constituent quark model, based on i) a
phenomenological Ansatz of the Bethe-Salpeter amplitude describing the
quark-pion vertex and ii) the Mandelstam description of the hadronic
tensor, we have investigated both generalized parton distributions and transverse
momentum distributions of the pion. The carefully comparison of our results
with
the available
i)...
Prof.
Alain Joye
(Institut Fourier, Université de Grenoble, France)
12/10/2011 11:20
We consider a model of a one-atom maser that consists in the following ingredients: a small reference system S corresponding to one mode of the EM field in a laser cavity, an infinite chain C of identical independent quantum subsystems E, corresponding to a sequence of atoms passing through the laser cavity, and heat reservoir R modeling the losses in the device. On the one hand the system S...
Prof.
Giuseppina Orlandini
(University of Trento)
13/10/2011 09:00
I intend first to introduce the response function as a general observable common to many fields of physics and describe how it can be calculated ab initio also in the continuum regime.
Then I will discuss results obtained in different frames for the 3-body system and for different operators. Quantitative estimates of the limits of the non relativistic quantum mechanical framework will be given.
Prof.
Aurora Tumino
(Laboratori Nazionali del Sud - INFN, Catania, Italy and \Universit\'a degli Studi di Enna "Kore", Enna Italy)
13/10/2011 09:40
According to our knowledge, the source of energy that sustains burning stars for millions to billions of years is represented by nuclear reactions which are responsible also for the continual conversion of one element to another inside them. Over the past fourty years nuclear physicists have been trying to measure the rates of the most relevant reactions, but there is still considerable...
Dr
Alessandra Guglielmetti
(Universita' degli Studi di Milano and INFN Milano)
13/10/2011 10:40
The LUNA (Laboratory for Underground Nuclear Astrophysics) experiment has been measuring nuclear cross sections of astrophysical interest since 1990. Two accelerators have been installed underground in the Gran Sasso laboratory where the cosmic bakground is very much reduced with respect to a laboratory on the Earth's surface. Therefore, a direct measurement of thermonuclear cross sections...
Dr
Michele Viviani
(INFN, Sezione di Pisa)
13/10/2011 11:20
In this contribution, we discuss some recent developments in the study of four-nucleon scattering. In the first part of the talk, we will focus on n-3H and p-3He elastic scattering below the trinucleon disintegration thresholds, where a detailed comparison between the phase-shifts calculated using three different theoretical approaches (the Alt, Grassberger-Sandhas, Hyperspherical-Harmonics,...
Paul-Antoine Hervieux
(Université de Strasbourg)
13/10/2011 15:00
A particularly attractive estimation of the coherence of a quantum system is provided by the Loschmidt echo (or quantum fidelity), which is a measure of the reversibility properties of the system. Most existing results are restricted to single-particle systems evolving in a given Hamiltonian. Our team has extended these studies to systems of interacting particles, revealing an anomalous...
Dr
Marcelo Yamashita
(Sao Paulo State University - Institute of Theoretical Physics)
13/10/2011 15:40
In this presentation we will review the role of scales in the physics of large three-body systems. It will be considered weakly-bound three particles with point-like interactions with a renormalization scheme characterized by the emergence of physical scales fixed by observables. The results will be presented in a form of universal scaling plots in the nuclear and atomic contexts. We will also...
Dr
Mario Gattobigio
(INLN, Nice-Sophia-Antipolis, France)
13/10/2011 16:40
The helium-atom clusters have been the object of intense investigation both from a theoretical and experimental point of view. The interaction between helium atoms is such that the 4He molecule is one of the biggest diatomic molecule in nature; in spite of a range interaction of lvdW ≈ 10.2 a.u., thus of a natural energy scale hbar**2 /m lvdW ≈ 400 mK, the binding energy of the molecule is E2...
M.
Nikolaj Zinner
(Aarhus University, Denmark)
13/10/2011 17:20
Recent success in the field of ultracold atomic gases has lead to the identification of universal low-energy three-body bound states as predicted by Efimov four decades ago. Some of these experiments are performed at such low temperatures that the three-body states have a background which can be a condensate or a degenerate Fermi gas. An interesting question is how this background will...
Prof.
Nir Barnea
(Racah Institute of Physics, Jerusalem, Israel)
14/10/2011 09:00
Photodisintegration is one of the basic tools through which we can study a microscopic system. In this work we have investigated the response of a trimer composed of 3 identical bosons to a photon like probe. In particular we have studied the quadrupole response of a shallow bosonic trimer, which in the long wavelength approximation is the leading contribution to the reaction cross-section.
M.
Oliver Kirsebom
(Aarhus University, Denmark and TRIUMF, Vancouver, Canada)
14/10/2011 09:40
Data from a recent experiment, in which the momenta of alpha particles from the three-alpha breakup of 12C resonances were measured, will be presented and compared to the predictions of different theoretical models. The following questions will be addressed: What can the momentum distribution of the alpha particles teach us about the symmetries and dynamics of the three-alpha system that forms...
Dr
Rimantas Lazauskas
(IPHC Strasbourg)
14/10/2011 10:40
Formalism based on complex-scaling method will be presented, which enables solution of the few-body scattering problem using trivial boundary conditions. Several applications will be presented proving efficiency of the method in describing elastic and three-body break-up reactions for Hamiltonians which may include both short-range and Coulomb interaction.
Dmitri Fedorov
(Aarhus University)
14/10/2011 11:20
Feshbach resonances are an experimental tool to effectively tune the inter-atomic interaction -- in particular, the scattering length -- in trapped cold gases. When the scattering length becomes large and negative, the condensed bose-gas collapses.
Theoretically condensates are often described using the Gross-Pitaevskii model with a variable-strength zero-range interaction which mimics...
Prof.
Sergei Rakityansky
(University of Pretoria)
14/10/2011 15:00
The N-channel Schroedinger equation has exactly N linearly independent regular solutions. Each of them is a column-matrix of the length N. Written next to each other, they form a square (N,N)-matrix, which is called the fundamental matrix of regular solutions. Any physical solution is a linear combination of its columns. Asymptotically, the fundamental matrix behaves as the superposition of...
M.
Jean-Marc Richard
(IPNL)
14/10/2011 15:40
Exotic atoms were first studied as the strong interaction supplementing the Coulomb potential in atoms where an electron is replaced by a negatively-charged hadron. The energy shift is usually rather accurately described by a formula due to Deser et al. and Truemann, except in the situation where the hadronic scattering becomes very large.
The problem can be generalised to a variety of...
Prof.
Mahir Hussein
(University of Sao Paulo)
The angular distributions for elastic scattering and breakup of halo nuclei are analysed using a near-side/far-side decomposition within the framework of the dynamical eikonal approximation. This analysis is performed for 11 Be impinging on Pb at 69 MeV/nucleon. These distributions exhibit very similar features. In particular they are both near-side dominated, as expected from...
