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Exotic gapless spectrum induced by frustration in quantum antiferromagnets

Federico Becca·Luca Capriotti·Alberto Parola·Sandro Sorella
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Abstract

We show strong numerical evidence in favor of an unexpected virtually gapless spectrum, with edge states localized at the boundaries, in frustrated spin-1/2 antiferromagnetic ladders with an odd number of legs. These features can be accurately reproduced by using a projected BCS wave function with a non-trivial pairing, that mixes even and odd reflection symmetries. This approach gives the correct classification of the excitations and provides a simple and very appealing picture of an unconventional spin-liquid phase stabilized by frustration.

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Federico Becca, Luca Capriotti, Alberto Parola, Sandro Sorella. 2007-01-26. Exotic gapless spectrum induced by frustration in quantum antiferromagnets. https://doi.org/10.1103/physrevb.76.060401

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