From its historical origins in the unusual behaviour of magnetic
impurities in metals, quantum impurity physics has served over the last
forty years as an important arena for the development of
new concepts and methods for treating correlated electron
systems. The remarkable progress of recent years in the
fabrication and design of nano-devices, has opened a new
world of possibilities hitherto inaccessible in bulk systems.
Following its first detection in semiconductor quantum
dots, the Kondo effect has been observed by now in numerous
nano-devices, each offering its own unique advantage. From the
exquisite control of microscopic parameters in semiconductor
quantum dots, to the accessibility of orbital degeneracy in
carbon nanotube dots, and electronic coupling to vibrational
modes in single-molecule transistors, these systems have
stimulated a host of new and fundamental theoretical questions.
These, in turn, have triggered significant progress in theoretical
methods for handling quantum impurity and related models, both in
and out of equilibrium. Recognizing the exciting experimental and
theoretical developments in the field, the intent of the
workshop/seminar was to bring together a wide range of
workers in the field, with two central aims in mind.
1. To provide a comprehensive, up-to-date perspective of
this rapidly developing field.
2. To promote communication and cooperation between
researchers, most especially between theorists and
experimentalists.
The main topics covered at the workshop/seminar
included:
• single-molecule transistors;
• dissipation, dephasing and non-equilibrium
physics in the presence of strong electronic
correlations;
• orbital physics in quantum dots;
• quantum criticality in confined nanostructures
and its comparison to heavy fermions;
• developments in theoretical approaches to
quantum impurities and related systems.
The mpipks proved to be an ideal venue for the meeting.
Its location, facilities and support, as well as the superb
organisation and extracurricular activities, were uniformly
commended by all participants. They in turn contributed immensely
to the success of the workshop/seminar, which
was certainly an international activity: researchers from 19
countries were present, with more than 70 participants in total.
These numbers would have been larger yet were it not for
inevitable space limitations -- some 15 applications had to
be rejected on these grounds. Highlight lectures included the
QIPN2M07 Colloquium, given by D. Goldhaber-Gordon (Stanford)
on observation of the two-channel Kondo effect in a
semiconductor nanostructure; lectures given by D. Ralph
(Cornell) and D. Natelson (Rice) about the fabrication and
aspects of strong correlations in molecular devices; and a
lecture given by N. Andrei (Rutgers) about new and exciting
developments in the theory of quantum impurities out of
equilibrium. Additional perspectives on a diverse array of
subjects were given by a range of 'senior scientists',
including T. Costi, K. Ensslin, M. Fabrizio, L. Glazman,
A. Hewson, K. Ingersent, H. Johannesson, H. R. Krishnamurthy,
H. Kroha, M. Lavagna, K. Le Hur, T. Pruschke, H. Schoeller,
Q. Si, F. Steglich, M. Vojta, F. von Oppen,
P. Wölfle, G. Zárand, and V. Zlatic.
One aim of the workshop/seminar was also to expose and encourage
active, but younger or less established researchers, working in
the field. They were well represented on the list of speakers
by F. Anders, C. Bolech, L. Borda, L. De Leo, G. Finkelstein, J. Folk, J. Paaske,
M. Pustilnik, and R. Zitko. Participants also had the opportunity to
present their work in two poster sessions, one each during the workshop and
seminar. With the same aim in mind, overview/tutorial lectures
were also incorporated into the workshop programme, leading overall
to an intellectually healthy balance between research talks, tutorials,
and ample time for the individual discussions that are so central
to science.
Reactions to the workshop/seminar were enthusiastic.
In particular, participants felt it had succeeded in solidifying the community
focused on quantum impurity physics, and hopes were frequently expressed
for future programmes of similar nature and goals aimed at this community.
The organisers would simply like to express their gratitude to
the mpipks for the hospitality and generous support that
made the venture possible.