Name: Quantum Matter in Low Dimensions: Opportunities and Challenges
Start: 2010-08-30T08:00:00+02:00
End: 2010-09-24T18:00:00+02:00
Location: Nordita

Monday, August 30, 2010

3:00 PM

3:00 PM - 4:00 PM
Room: 132:028
Tuesday, August 31, 2010
Wednesday, September 1, 2010
1:30 PM Topological Entanglement in Fractional Quantum Hall Excitation Eigenstates - Zlakto Papic (Institute of Physics)
Topological Entanglement in Fractional Quantum Hall Excitation Eigenstates
- Zlakto Papic (Institute of Physics)
1:30 PM - 2:30 PM
Room: 132:028 Zlatko Papic: Entanglement in topological ordered states has so far been investigated through the perspective of the ground-state wave function. By presenting entanglement spectra of the (quasihole) excitations of fractional quantum Hall states, I will show their typical structure in Abelian, as well as non- Abelian cases of the Read-Rezayi sequence, including the realistic Coulomb-interaction ground states that they are believed to describe. I will argue that the excitation wave functions contain sufficient information to identify the system's topological order.
Thursday, September 2, 2010
11:00 AM Commensurability effects caused by the modulated spin-orbit interaction in one-dimensional electron liquids - Gia Japaridze (Andronikashvili Institute of Physics)
Commensurability effects caused by the modulated spin-orbit interaction in one-dimensional electron liquids
- Gia Japaridze (Andronikashvili Institute of Physics)
11:00 AM - 12:00 PM
Room: 132:028 (with H. Johannesson, M. Malard and H. Strom)
1:30 PM Narrow-gap semiconductors with strong Coulomb repulsion - Vadim Cheianov (Lancaster University)
Narrow-gap semiconductors with strong Coulomb repulsion
- Vadim Cheianov (Lancaster University)
1:30 PM - 2:30 PM
Room: 132:028
Friday, September 3, 2010
10:00 AM Breaking integrability and confinement in 2d statistical models - Giuseppe Mussardo (SISSA)
Breaking integrability and confinement in 2d statistical models
- Giuseppe Mussardo (SISSA)
10:00 AM - 11:00 AM
Room: 132:028
11:00 AM Extended global symmetry of the Hubbard model on bipartite lattices - Jose Carmelo (Department of Physics, University of Minho)
Extended global symmetry of the Hubbard model on bipartite lattices
- Jose Carmelo (Department of Physics, University of Minho)
11:00 AM - 12:00 PM
Room: 132:028 J. M. P. Carmelo, Stellan Östlund, and M. J. Sampaio The Hubbard model on a bipartite lattice is one of the most studied many- particle quantum problems. However, except in one dimension the model has no exact solution and there remain many open questions about its properties. Here we report a recent exact result [1]. According to it, for on-site interaction U 6= 0 the local SU(2) × SU(2) × U(1) gauge symmetry of the Hubbard model on a bipartite lattice with vanishing transfer integral t = 0 studied in [2] can be lifted to a global [SU(2)× SU(2)× U(1)]/Z2 2 = SO(3) ×SO(3) ×U(1) symmetry in the presence of the kinetic-energy hopping term of the Hamiltonian with t > 0. The generator of the new found hidden independent charge global U(1) symmetry, which is not related to the ordinary U(1) gauge subgroup of electromagnetism, is one half the rotated- electron number of singly-occupied sites operator. Although addition of chemicalpotential and magnetic-field operator terms to the model Hamiltonian lowers its symmetry, such terms commute with it. Therefore, its energy eigenstates refer to representations of the new found global SO(3) × SO(3) × U(1) = [SO(4) × U(1)]/Z2 symmetry, which is expected to have important physical consequences. Our studies reveal that for U/4t > 0 the model charge and spin degrees of freedom are associated with U(2) = SU(2) × U(1) and SU(2) symmetries [1], respectively, rather than with two SU(2) symmetries. (The latter case would hold if the model global symmetry was only SO(4) = [SU(2) ×SU(2)]/Z2.) The occurrence of such charge U(2) = SU(2) × U(1) symmetry and spin SU(2) symmetry is for the onedimensional model behind the different ABCDF and ABCD forms of the charge and spin monodromy matrices, respectively, found by the inverse scattering method exact solution [3].<br /> 1. J.M.P. Carmelo, Stellan Östlund, and M.J. Sampaio, Ann.Phys. 325, 1550 (2010).<br /> 2. Stellan Östlund and Eugene Mele, Phys.Rev. B 44, 12413 (1991).<br /> 3. M.J. Martins and P.B. Ramos, Nucl.Phys. B 522, 413 (1998).
2:30 PM What can graphene teach us about the bridge between quantum field theory and kinetic theory? - Janik Kailasvuori (MPIPKS (Dresden))
What can graphene teach us about the bridge between quantum field theory and kinetic theory?
- Janik Kailasvuori (MPIPKS (Dresden))
2:30 PM - 3:30 PM
Room: 132:028 Semiclassical spin-coherent kinetic equations can be derived from quantum theory with many different formalisms. For 2d Dirac electrons (e.g. in graphene, 3d topological insulators, ...) we found to our surprise that well established formalisms give different results. We have been able to point out the exact source of the discrepancy and raise fundamental questions about how to derive semiclassical kinetic equation when some quantum coherence must be retained. Further, in monolayer graphene we make the unintuitive finding that there could be finite electron-hole coherent quantum effects even far away from the point where electron and hole bands touch.
Saturday, September 4, 2010
Sunday, September 5, 2010

Monday, September 6, 2010
Tuesday, September 7, 2010
Wednesday, September 8, 2010
Thursday, September 9, 2010
Friday, September 10, 2010
Saturday, September 11, 2010
Sunday, September 12, 2010