Speaker
Sergei RUTKEVICH
(Institute of Solid State and Semiconductor Physics)
Description
The kink topological excitations are quite common in the
two dimensional field theories with Hamiltonian invariant
under some discrete symmetry group. If such symmetry is
spontaneously broken in the ordered phase, the latter has a
discrete set of degenerate vacuums. The kinks separating
two different vacuums behave like stable quantum particles
which can propagate in the system. Adding a small
interaction, which explicitly breaks the Hamiltonian
symmetry, lifts the degeneracy of ground states and leads
to confinement of kinks. This simple scenario of
confinement is realized in many two dimensional models.
I review recent progress in understanding of the kink
confinement in the quantum Ising spin chain, and in its
continuum limit - Ising field theory, which correspond to the
symmetry group Z2. This progress has been achieved due
to the Bethe-Salpeter equation approach introduced by
Fonseca and Zamolodchikov.
