39 research outputs found
Interface states of quantum spin systems
We review recent results as well as ongoing work and open problems concerning
interface states in quantum spin systems at zero and finite temperature.Comment: 10 pages, LaTe
Rigidity of interfaces in the Falicov-Kimball model
We analyze the thermodynamic properties of interfaces in the
three-dimensional Falicov Kimball model, which can be viewed as a primitive
quantum lattice model of crystalline matter. In the strong coupling limit, the
ionic subsystem of this model is governed by the Hamiltonian of an effective
classical spin model whose leading part is the Ising Hamiltonian. We prove that
the 100 interface in this model, at half-filling, is rigid, as in the
three-dimensional Ising model. However, despite the above similarities with the
Ising model, the thermodynamic properties of its 111 interface are very
different. We prove that even though this interface is expected to be unstable
for the Ising model, it is stable for the Falicov Kimball model at sufficiently
low temperatures. This rigidity results from a phenomenon of "ground state
selection" and is a consequence of the Fermi statistics of the electrons in the
model.Comment: 79 pages, 9 figures included as ps-files, appendix added in revisio
A model with simultaneous first and second order phase transitions
We introduce a two dimensional nonlinear XY model with a second order phase
transition driven by spin waves, together with a first order phase transition
in the bond variables between two bond ordered phases, one with local
ferromagnetic order and another with local antiferromagnetic order. We also
prove that at the transition temperature the bond-ordered phases coexist with a
disordered phase as predicted by Domany, Schick and Swendsen. This last result
generalizes the result of Shlosman and van Enter (cond-mat/0205455). We argue
that these phenomena are quite general and should occur for a large class of
potentials.Comment: 7 pages, 7 figures using pstricks and pst-coi
Recommended from our members
Interface states of quantum spin systems
We review recent results as well as ongoing work and open problems concerning
interface states in quantum spin systems at zero and finite temperature
Recommended from our members
A model with simultaneous first and second order phase transitions
We introduce a two dimensional nonlinear XY model with a second order phase
transition driven by spin waves, together with a first order phase transition in the bond
variables between two bond ordered phases, one with local ferromagnetic order and another
with local antiferromagnetic order. We also prove that at the transition temperature the
bond-ordered phases coexist with a disordered phase as predicted by Domany, Schick and
Swendsen. This last result generalizes the result of Shlosman and van Enter
(cond-mat/0205455). We argue that these phenomena are quite general and should occur for a
large class of potentials
Recommended from our members
Rigidity of interfaces in the Falicov-Kimball model
We analyze the thermodynamic properties of interfaces in the three-dimensional
Falicov Kimball model, which can be viewed as a primitive quantum lattice model of
crystalline matter. In the strong coupling limit, the ionic subsystem of this model is
governed by the Hamiltonian of an effective classical spin model whose leading part is the
Ising Hamiltonian. We prove that the 100 interface in this model, at half-filling, is
rigid, as in the three-dimensional Ising model. However, despite the above similarities
with the Ising model, the thermodynamic properties of its 111 interface are very different.
We prove that even though this interface is expected to be unstable for the Ising model, it
is stable for the Falicov Kimball model at sufficiently low temperatures. This rigidity
results from a phenomenon of "ground state selection" and is a consequence of the Fermi
statistics of the electrons in the model
Coherent measurement of short laser pulses based on spectral interferometry resolved in time
International audienc
Third order nonlinearity characterisation of optical waveguides
International audienc