XIII Training Course in the Physics of Strongly Correlated Systems
Vietri sul Mare (Salerno) Italy
6 - 17 October 2008
Lecture Topics and Background References
Department of Physics and Astronomy, University College London, United Kingdom
Quantum magnetism in insulators
Lectures:
1. Single impurities in semiconductors and insulators - analogies with
atomic physics, hyperfine interactions, and free electron laser
2. 1-dimensional magnets, including direct evidence for fermionic quasiparticles
in antiferromagnetic S=1/2 chains, and quantum phase coherence and edge states
in S=1 chains.
3. 2-dimensional magnets, including entanglement at short distances
4. 3-dimensional magnets - quantum phase transition, decoherence due to coupling
to nuclear spin bath
5. Undoped and doped Kondo insulators
Tutorials:
Journal club
References:
General Background: “What Happens to Ordered Moments When They are no
Longer Ordered?”, G. Aeppli, Physica B, 318, p. 5-11, (2002). “Seeing the Spins
in Solids”, G. Aeppli, S. Hayden, T. Perring, Physics World, p. 33-37, (December
1997)
2. “Direct Observation of Field-Induced Incommensurate Fluctuations in a
One-Dimensional S = ½ Antiferromagnet”, D. C. Dender, P. R. Hammar, D. H. Reich,
C. Broholm, G. Aeppli, Phys. Rev. Lett. 79(9), p. 1750-1753, (1997). “Mesoscopic
Phase Coherence in a Quantum Spin Fluid” Guangyong Xu, C. Broholm, Yeong-AhSoh,
G. Aeppli, J. F. DiTusa, Ying Chen, M. Kenzelmann, C. D. Frost, T. Ito, K. Oka,
H. Takagi Science 317, p. 1049–1052 (2007)
3. “Quantum dynamics and entanglement of spins on a square lattice” N. B.
Christensen, H. M. Rønnow, D. F.McMorrow, A. Harrison, T. G. Perring, M. Enderle,
R. Coldea, L. P. Regnault, G. Aeppli PNAS 104 15264-15269 (2007)
4. "Quantum Critical Behavior for a Model Magnet”, D. Bitko, T. F. Rosenbaum, G.
Aeppli, Phys. Rev. Lett.77(5), p. 940-943, (1996). “Tunable Quantum Tunneling of
Magnetic Domain Walls” J. Brooke, T. F. Rosenbaum, G. Aeppli, Nature 413, p. 610
- 613 (2001). “Quantum phase transition in a spin bath”, H. M. Ronnow, R.
Parthasarathy, J. Jensen, G. Aeppli, T. F. Rosenbaum, and D. F. McMorrow,
Science 308, p. 392-395 (2005)
5. "Kondo Insulators", G. Aeppli, Z. Fisk, Comments Cond. Matt. Phys. 16, p.
155, (1992). "Unconventional Charge Gap Formation in Cubic FeSi", Z. Schlesinger,
Z. Fisk, Hai-Tao Zhang, B. Maple, J. F. DiTusa and G. Aeppli, Phys. Rev. Lett.
71, p. 1748, (1993). “Magnetoresistance from Quantum Interference Effects in
Ferromagnets”, N. Manyala, Y. Sidis, J. F. Ditusa, G. Aeppli, D. P. Young, Z.
Fisk, Nature 404, p. 581-584, (2000). “Doping a semiconductor to create an
unconventional metal” N. Manyala, J.F. DiTusa, G.Aeppli, A.P.Ramirez Nature 454
976–980 (2008)
Department of Physics, University of Cambridge, United Kingdom
Novel quantum condensates in excitonic matter
This course will interleave discussion of a novel physical problem of a new kind
of Bose-Einstein condensate with teaching of the fundamental theoretical tools
of quantum condensed matter field theory.
Lectures:
1. Introduction to the physical systems. The electron-hole gas, excitonic
insulator; exciton-photon interactions, polaritons and the Dicke Model; exciton
and polariton BEC.
2. Theoretical tools: Second quantization. Coherent states. Coherent state path
integral. Examples of coherent state mean field theories: Dilute Bose gas. BCS
superconductivity.
3. Exciton and polariton condensates in mean field theory. Field theory of
polariton condensate; BEC-BCS crossover.
4. Theoretical Tools: Open systems and Keldysh formulation. Pair-breaking and
the semiconductor laser.
5. Phase-breaking and open system dynamics. Review of experiment. Open questions
and new systems.
Tutorials:
Journal club
References:
The methodological aspects are covered in standard quantum field theory texts:
Professor Littlewood's approach will be closest to the book of Altland and
Simons [1]. A recent theoretically focussed review of polariton systems is [2].
1. A. Altland, and B.D. Simons; Condensed Matter Field Theory; Cambridge
University Press (2006).
2. J. Keeling, F.M. Marchetti, M.H. Szymanska, and P.B. Littlewood; Collective
coherence in planar semiconductor microcavities; Semiconductor Science and
Technology 22, R1 (2007).
Institut für Theoretische Physik, ETH Zürich, Switzerland
Introduction to Unconventional Superconductivity
Lectures:
1. Generalized BCS Theory.
2. Phenomenological Approach and Symmetry Aspects.
3. Josephson and Tunneling Effects.
4. Case Studies I.
5. Case Studies II.
Tutorials:
1. Generalized BCS Theory: Bogolyubov-transformation and self-consistent
equations.
2. Generalize Ginzburg-Landau Theory: Free energy and phases of a two-component
order parameter.
3. Generalize Ginzburg-Landau Theory: Boundary properties of time reversal
symmetry breaking phase.
4. High-Tc-superconductivity: Simple model of an RVB state.
References
1. V.P. Mineev, and K.V. Samokhin; Introduction to Unconventional
Superconductivity; Gordon & Breach Publisher (1998).
2. M. Sigrist, and K. Ueda; Phenomenological Theory of Unconventional
Superconductivity; Rev. Mod. Phys. 63, 239 (1991).
3. M. Sigrist; Introduction to Unconventional Superconductivity; AIP Conference
Proceedings 789, 165 (2005).
Institut für Theoretische Physik, ETH Zürich, Switzerland
Quantum Monte Carlo methods
Lectures:
1. Introduction to Monte Carlo simulations.
2. Classical and quantum cluster algorithms.
3. The worm algorithm.
4. Optimized ensembles for classical and quantum Monte Carlo simulations.
5. Continuous time QMC solvers for quantum impurity problems and DMFT.
Tutorials:
ALPS Monte Carlo codes
References:
1. D.P. Landau, and K. Binder; A Guide to Monte Carlo Simulations in Statistical
Physics; Cambridge University Press (2005).
2. R.H. Swendsen, and J.-S. Wang; Phys. Rev. Lett. 58, 86 (1987). H.G. Evertz;
Adv. Phys. 52, 1 (2003).
3. N.V. Prokof'ev et al.; Sov. Phys. - JETP 87, 310 (1998). A.W. Sandvik; Phys.
Rev. B 59, 14157 (1999). O.F. Syljuasen, and A.W. Sandvik; Phys. Rev. E 66,
046701 (2002). F. Alet et al.; Phys. Rev. E 71, 036706 (2005).
4. F. Wang, and D.P. Landau; Phys. Rev. Lett. 86, 2050 (2001); Phys. Rev. E 64,
056101 (2001). M. Troyer et al.; Phys. Rev. Lett. 90, 120201 (2003). S. Trebst
et al.; Phys. Rev. E 70, 046701 (2004). S. Wessel et al.; J. Stat. Mech. P12005
(2007).
5. A.N. Rubtsov; Phys. Rev. B 72 035122 (2005). P. Werner et al.; Phys.
Rev. Lett. 97, 076405 (2006). P. Werner et al.; Phys. Rev. B 74, 155107 (2006).
E. Gull et al.; Europhysics Letters 82, 57003 (2008).
