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FRACTIONALLY CHARGED EXCITATIONS ON FRUSTRATED LATTICES.

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Title: FRACTIONALLY CHARGED EXCITATIONS ON FRUSTRATED LATTICES.
Authors: RUNGE, E.1, POLLMANN, F.2, FULDE, P.2
Source: International Journal of Modern Physics B: Condensed Matter Physics; Statistical Physics; Applied Physics. 5/30/2007, Vol. 21 Issue 13/14, p2215-2231. 17p. 9 Diagrams, 2 Graphs.
Subjects: Lattice theory, Quasiparticles, Force & energy, Dynamics, Physics
Abstract: Systems of strongly correlated fermions on certain geometrically frustrated lattices at particular filling factors support excitations with fractional charges ±e/2. We calculate quantum mechanical ground states, low–lying excitations and spectral functions of finite lattices by means of numerical diagonalization. The ground state of the most thorough-fully studied case, the criss-crossed checkerboard lattice, is degenerate and shows long–range order. Static fractional charges are confined by a weak linear force, most probably leading to bound states of large spatial extent. Consequently, the quasi-particle weight is reduced, which reflects the internal dynamics of the fractionally charged excitations. By using an additional parameter, we fine–tune the system to a special point at which fractional charges are manifestly deconfined—the so–called Rokhsar–Kivelson point. For a deeper understanding of the low–energy physics of these models and for numerical advantages, several conserved quantum numbers are identified. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:Systems of strongly correlated fermions on certain geometrically frustrated lattices at particular filling factors support excitations with fractional charges ±e/2. We calculate quantum mechanical ground states, low–lying excitations and spectral functions of finite lattices by means of numerical diagonalization. The ground state of the most thorough-fully studied case, the criss-crossed checkerboard lattice, is degenerate and shows long–range order. Static fractional charges are confined by a weak linear force, most probably leading to bound states of large spatial extent. Consequently, the quasi-particle weight is reduced, which reflects the internal dynamics of the fractionally charged excitations. By using an additional parameter, we fine–tune the system to a special point at which fractional charges are manifestly deconfined—the so–called Rokhsar–Kivelson point. For a deeper understanding of the low–energy physics of these models and for numerical advantages, several conserved quantum numbers are identified. [ABSTRACT FROM AUTHOR]
ISSN:02179792
DOI:10.1142/S0217979207043609