08:45  09:00

Roderich Moessner (MPIPKS) & Scientific Coordinators
Opening

09:00  09:40

Mario Gattobigio
(Université de Nice  Sophia Antipolis)
Efimov physics and nuclear physics: where are we?
Efimov Physics originated from a reflection on nuclear
physics and in particular from the observation that
the light nuclei spectrum presents shallow states,
the deuteron and the triton.
Afterwards, the possibility to change and tune the interparticle
interaction made atomic physics the privileged
playground of Efimov physics allowing fantastic achievements
both from the experimental and theoretical sides.
In the last few years there is a renewed effort bring
Efimov physics back to the origins, back to nuclear
physics, and in this talk I'll try to understand where
we are now in this challenge.

09:40  10:20

Petar Stipanović
(University of Split)
Stability and universality of fewbody systems
Ground state properties of weakly bound fewbody systems consisting of helium and spinpolarized hydrogen isotopes, and alkali atoms have been explored.
Stability of different cluster species has been tested with a special emphasis on a universality of quantum halo states  weakly bound systems with a radius extending well into the classically forbidden region.
The study of realistic systems is supplemented by model calculations in order to analyze how lowenergy properties depend on the interaction potential.
The use of variational and diffusion Monte Carlo methods enabled very precise calculation of both size and binding energy of fewbody systems.
Using dimensionless measures of the binding energy and cluster size, studied atomic clusters are compared to other known halos in different fields of physics.
Different characteristic scaling lengths, which make sizeenergy ratio to be universal, are tested.
As the scaled binding energy decreases, samba and tango type trimers separate from Borromean type~[1].
Research is extended to tetramers and pentamers.
Furthermore, the structural properties of different trimers are compared with the most recent experimental results~[2,3] obtained by Coulomb explosion imaging of diffracted clusters.
[1] Stipanovi\'{c} P. et al., Phys. Rev. Lett. \textbf{113}, 253401 (2014).
[2] Voigtsberger J. et al., Nature Communications \textbf{5}, 5765 (2014).
[3] Kunitski M. et al., Science \textbf{348}, 551 (2015).

10:20  10:50

Coffee break

10:50  11:30

Doerte Blume
(The University of Oklahoma)
Fewbody physics of spinorbit coupled cold atom systems
This talk considers selected aspects of spinorbit coupled fewatom systems. Spinorbit coupling, which leads to a locking of the spin and the spatial degrees of freedom, can be realized in cold atom systems in a variety of ways. This contribution discusses the modifications of the fewbody dynamics due to the spinorbit coupling. Scattering and bound state properties will be considered.

11:30  12:10

Yusuke Nishida
(Tokyo Institute of Technology)
Zoo of quantum halos
Waveparticle duality in quantum mechanics allows for a halo bound state whose spatial extension far exceeds a range of the interaction potential. What is even more striking is that such quantum halos can be arbitrarily large on special occasions. The two examples known so far are the Efimov effect and the super Efimov effect, which predict that spatial extensions of higher excited states grow exponentially and doubleexponentially, respectively [1,2]. Here we establish yet a new class of arbitrarily large quantum halos formed by spinless bosons with shortrange interactions in two dimensions [3]. When the twobody interaction is absent but the threebody interaction is resonant, four bosons exhibit an infinite tower of bound states whose spatial extensions scale as $R_n\sim e^{(\pi n)^2/27}$ for large $n$. The emergent scaling law is universal and termed a semisuper Efimov effect, which together with the Efimov and super Efimov effects constitutes a trio of fewbody universality classes allowing for arbitrarily large quantum halos.
[1] V. Efimov, "Energy levels arising from resonant twobody forces in a threebody system," Phys. Lett. B 33, 563564 (1970).
[2] Y. Nishida, S. Moroz, and D. T. Son, "Super Efimov effect of resonantly interacting fermions in two dimensions," Phys. Rev. Lett. 110, 235301 (2013).
[3] Y. Nishida, "Semisuper Efimov effect of twodimensional bosons at a threebody resonance," to be published in Phys. Rev. Lett. (2017).

12:10  12:50

Betzalel Bazak
(Institut de Physique Nucléaire Orsay)
Universal states and Efimov physics in fermionic mixtures
The system of few identical fermions interacting resonantly with a distinguishable atom exhibits a rich and interesting physics, including universal states and the celebrated Efimov effect.
The (2+1) system, composed of two heavy fermions and lighter atom, supports a universal trimer state if the ratio of the particle masses exceeds critical value. For even larger mass ratio the system becomes Efimovian, introducing a threebody scale and showing geometric series of bound states.
Interestingly, this trend continues in the (3+1) system as well as in the (4+1) system, having their own universal states and pure (N+1)body Efimov effects.
Adding another particle, however, this series seems to stop. This should be a sign of a shell structure and screening effects, which may shed light on the crossover from the fewbody systems to the manybody polaron case.

12:50  14:40

Lunch and discussion

14:40  15:20

Eduardo Garrido
(Spanish National Research Council)
Connection between two and threebody systems in an oscillator trap and Ddimensional calculations
In this work we investigate threebody systems when
the dimension changes in a continuous way from three (3D)
to two (2D) dimensions. This amounts to confining the particles
into a narrower and narrower layer, such that, eventually, when
the layer has zero width, the particles are forced to move in 2D.
In practice, this can be done by putting the particles under
the effect of an external trap potential confining the particles
in the space. In particular, this can be done by means of a
harmonic oscillator potential in the zcoordinate.
For twobody systems the numerical implementation of the external
field is simple, and it does not present particular problems.
However, for threebody systems, although conceptually the procedure
is exactly the same, the numerical difficulties increase when the
frequency of the harmonic oscillator increases. In fact, for very
large frequencies, i.e., when approaching 2D, the method is
quite inefficient. For this reason, in this work we propose
to implement the confinement of the particles, not by
means of an external potential, but by introducing the dimension
d as a parameter in the Schrödinger (or Faddeev) equations to be
solved. The dimension is then allowed to take noninteger values
within the range 2 ≤ d ≤ 3.
The purpose of this work is twofold. First, we want to
see the connection between the two confinement methods
mentioned above. It is necessary to see the equivalence between
a given value of the confining harmonic oscillator
frequency and the dimension d describing the same physical
situation. Once this is done, we shall use the second
method, which is numerically much simpler, to investigate
the Efimov states in mass imbalanced systems, focusing
in particular on how those states disappear when
increasing the confinement of the particles.

15:20  16:00

Marcelo Yamashita
(Sao Paulo State University)
Dimensional effects in threebody systems
Some phenomena in threebody systems can be drastically affected by the dimension where the system is inserted. The Efimov effect is a remarkable example: it exists only in three spatial dimensions. However, if we consider noninteger dimensions, the Efimov effect is allowed for dimensions (d) in the interval 2.3 < d < 3.8, where this result holds for three identical bosons. In this presentation I will show a very simple method to extend this interval for a general AAB system. I will also show a framework for studying the threebody problem as one continuously changes the dimensionality of the system. Some interesting results for two dimensions will be detailed.

16:00  16:30

Coffee break

16:30  17:30

Ramin Golestanian
(University of Oxford)
Gutzwiller Colloquium: Making Living Matter from the bottom up

18:00  18:40

Anna Okopińska
(Jan Kochanowski University)
Entanglement characteristics of bound and resonant fewbody states

18:40  19:20

Tobias Frederico
(Aeronautic Institute of Technology)
Discrete scaling in the heavy and heavylight molecule scattering

19:20  20:30

Dinner
