Leiden University, The Netherlands

14 June - 2 July 1999


D. Khomskii (Groningen)
J.A. Mydosh (Leiden)
J. Zaanen (Leiden)

This three-week workshop will focus upon three modern topics of particular
current interest in the rapidly developing field of "quantum magnetism".
The latter terms we use collectively to represent a newly emerging subfield
of condensed matter physics where new magnetic materials play a major role.
Here a variety of novel phenomena occur, such as quantum phase transition,
spin liquids, phase separations, etc., and generate complex organizations
in strongly interacting quantum matter.

Our three topics of attention are:

i) Stripe phases of low-dimensional oxide materials where there occur phase
separations in real space of charge and spin into ordered regions. The
associated phase transitions modify the magnetic, electronic and
superconducting properties such that a unique quantum ground state is

ii Strongly interacting magnetic materials possessing unusual behaviors
related to colossal magneto-resistance, metal/insulator transitions and
orbital ordering. Attention will concentrate on the understanding and
control of the magnetic interactions and how these influence the electronic
and structural properties.

iii Nanomagnetism includes the artificial structuring of magnetic materials
on a sub micron level and natural occurring magnetic entities such as
molecules and clusters. Here the emphasis will be on the macroscopic
behaviors found in single domains of quantum spins, quantum coherence,
dissipation and tunneling of magnetization, and disorder and frustration

List of participants/lecturers:

G. Aeppli (NEC-Princeton)
A. Balatsky (Los Alamos)
B. Barbara (Grenoble)
B. Buechner (Cologne)
C. Castellani (Roma)
C. Di Castro (Roma)
A. Castro-Neto (Riverside)
K. Kikoin (Beer-Sheva)
T. Kimura (Tsukuba)
P. Kopietz (Goettingen)
D. Loss (Basel)
A. Millis (John Hopkins)
T. Mizokawa (Tokyo)
H. Mook
A. Moreo (Florida)
N. Nagaosa (Tokyo)
S. Sachdev (Yale)
P. Stamp (Vancouver)
J. Tranquada (Brookhaven)
S. Uchida (Tokyo)
K. Ueda (Tokyo)

It is hoped through a minimum of formal seminars and lectures and a maximum
of small informal discussions and interactions that significant advance
will be made in the above areas. Although no proceedings of the workshop
will appear it is expected that participants will use the stimulations and
exchanges at the Lorentz Center as a source for future publications and
contributions to the field.

Preliminary Program

Please note that other participants will have ample time to
present results in talks, to be scheduled during the workshop.

Monday June 14
11.00 Organizational Meeting
14.00 Kimura (manganites)
17.00 Cheese and wine party

Tuesday June 15
9.30 Nagaosa (manganites)
11.00 Mydosh

Wednesday June 16
9.30 Castro-Neto
14.00 Nieuwenhuizen

Thursday June 17
9.30 Di Castro
11.00 Kikoin
13.30-16.00 Stripe discussion (Nagaosa, Di Castro, Brom)

16.00 Lecture hall 032 (ground floor):  Jorrit Jorritsma
Magnetic and electrical transport properties of metallic nanowires

Organized dinner

Friday June 18
9.30 Loss: Spin Tunneling in Nanomagnets
11.00 Stamp: Coherence and Decoherence in the Quantum Dynamics of Nanomagnets
13.30 Nanomagnetism discussion

Monday June 21
9.30 Imai
11.00 Wernsdorfer
17.00 Cheese and wine party

Tuesday June 22
9.30 Sachdev
11.00 Barbara
14.00 Discussion: Quantum magnetism and nanomagnetism
14.00 Theoretical seminar Instituut-Lorentz (room 276 Oort building):
T.C. Choy (National Center for Theoretical Sciences, Taiwan):
The meaning of "counterfactual" statements and non-locality in quantum mechanics

Wednesday June 23
9.30 Tranquada
11.00 Morais Smith/Mostovoy
14.00 Discussion: Stripes

Thursday June 24
Excursion to the Delta Project (Zeeland)
Organised dinner

Friday June 25
9.30 Mook
11.00 Varma (not certain)

Monday June 28
9.30 Uchida
11.00 Moreo
17.00 Cheese and wine party

Tuesday June 29
9.30 Aeppli
11.00 Zachar

Wednesday June 30
9.30 Palstra
11.00 Ueda
14.00 Werner

Thursday July 1
9.30 Mizokawa
11.00 Van der Marel
Organised dinner

Friday July 2
9.30 Eder
11.00 Kopietz

For further information, please contact:

Annette Vermond, Management and Program Assistant.

Lorentz Center, Niels Bohrweg 2, 2333 CA Leiden, the Netherlands.

Tel: +31 71 5275400, Fax: +31 71 5275415, email: