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Mater Sci Nanotechnol 2017
Volume 1 Issue 3 Magnetic Materials 2017
October 09-10, 2017 London, UK
International Conference on
Yshai Avishai, Materials Science and Nanotechnology
Magnetic Impurities in cold atom systems
Motivated by the impressive recent advance in
manipulating cold fermionic atoms I will focus
on two problems involving magnetic impurities.
Experimentally it requires the preparation of a Fermi
sea of cold atoms that are confined by a shallow
harmonic potential and a trapping of a few other atoms
(that serve as magnetic impurities) in specially designed
optical potential. When there is an antiferromagnetic
exchange interaction between the itinerant atoms in the
Fermi sea and the localized magnetic impurity it gives
rise to the Kondo effect. The first problem employs
the fact that fermionic atoms can have spin s>1/2 and
thereby the magnetic impurity is over-screened. At
low temperature, such system displays a non-Fermi
liquid behavior. We establish a theoretical analysis
of interacting cold fermionic atomic systems that are
governed by an effective Hamiltonian whose low energy
physics displays an over-screening by large spin. In
addition, we indicate candidate systems in which it
can be experimentally realized. In the second part, we
explore and substantiate the feasibility of realizing the
Coqblin-Schrieffer model in a gas of cold fermionic Yb
atoms. Making use of different AC polarizabillities of the
electronic ground state) and the long lived metastable
state, it is substantiated that the latter can be localized
and serve as a magnetic impurity while the former
remains itinerant. The exchange mechanism between
the itinerant 1S0 and the localized 3P0atoms is analyzed
and shown to be antiferromagnetic. The ensuing
SU(6) symmetric Coqblin-Schrieffer Hamiltonian is
constructed. A number of thermodynamic measurable
observables are calculated in the weak coupling regime
$T>T_K$ (using perturbative RG analysis) and in the
strong coupling regime $T<T_K$ (employing known
Bethe ansatz techniques).
Biography
Yshai Avishai did PhD at Weizmann institute. He is a professor of theoretical
condensed matter Physics at Ben Gurion University, Beer Sheva Israel. He is a
fellow of the American Physical Society, served as a Divisional Associate Editor for
Physical Review Letters, was an Outstanding Referee for APS journals. He served
as head of the Physics Department at Ben Gurion University, as head of the Ilse-
Katz Center for Nanotechnology, as member of the Judging Committees for Israel
prize in Physics and the Emet prize for exact Sciences. He is the author of 235
papers in high-level journals including Physical Review Letters and Nature, and
an author of three books in Physics. He occasionally serves as Faculty Member
at NYU-Shanghai University and YITP at Kyoto University, Japan. He visited
and worked in numerous institutes around the world, Including Argonne National
Laboratories, Lyon, Saclay, Orsay, Heidelberg, Tokyo, Kyoto, Hokkaido and others.
Yshai Avishai
Ben Gurion University (Israel), NYU-Shanghai (China) and YITP (Japan)