Europhys. Lett.
Volume 75, Number 1, July 2006
Page(s) 133 - 138
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 31 May 2006
Europhys. Lett., 75 (1), pp. 133-138 (2006)
DOI: 10.1209/epl/i2006-10092-x

On confined fractional charges: A simple model

F. Pollmann and P. Fulde

Max-Planck-Institut für Physik komplexer Systeme Nöthnitzer-Str. 38, 01187 Dresden, Germany

received 28 March 2006; accepted in final form 15 May 2006
published online 31 May 2006

We address the question whether features known from quantum chromodynamics (QCD) can possibly also show up in solid-state physics. It is shown that spinless fermions of charge e on a checkerboard lattice with nearest-neighbor repulsion provide for a simple model of confined fractional charges. After defining a proper vacuum the system supports excitations with charges $\pm e/2$ attached to the ends of strings. There is a constant confining force acting between the fractional charges. It results from a reduction of vacuum fluctuations and a polarization of the vacuum in the vicinity of the connecting strings.

71.27.+a - Strongly correlated electron systems; heavy fermions.
71.10.Fd - Lattice fermion models (Hubbard model, etc.).
71.10.-w - Theories and models of many-electron systems.

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