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arXiv · 0805.0255

Strong-Coupling Phases of Frustrated Bosons on a 2-leg Ladder with Ring Exchange

D. N. Sheng·Olexei I. Motrunich·Simon Trebst·Emanuel Gull·Matthew P. A. Fisher
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Abstract

Developing a theoretical framework to access quantum phases of itinerant bosons or fermions in two dimensions (2D) that exhibit singular structure along surfaces in momentum space but have no quasi-particle description remains as a central challenge in the field of strongly correlated physics. In this paper we propose that distinctive signatures of such 2D strongly correlated phases will be manifest in quasi-one-dimensional "N-leg ladder" systems. Characteristic of each parent 2D quantum liquid would be a precise pattern of 1D gapless modes on the N-leg ladder. These signatures could be potentially exploited to approach the 2D phases from controlled numerical and analytical studies in quasi-1D. As a first step we explore itinerant boson models with a frustrating ring exchange interaction on the 2-leg ladder, searching for signatures of the recently proposed two-dimensional d-wave correlated Bose liquid (DBL) phase. A combination of exact diagonalization, density matrix renormalization group, variational Monte Carlo, and bosonization analysis of a quasi-1D gauge theory, all provide compelling evidence for the existence of a new strong-coupling phase of bosons on the 2-leg ladder which can be understood as a descendant of the two-dimensional DBL. We suggest several generalizations to quantum spin and electron Hamiltonians on ladders which could likewise reveal fingerprints of such 2D non-Fermi liquid phases.

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D. N. Sheng, Olexei I. Motrunich, Simon Trebst, Emanuel Gull, Matthew P. A. Fisher. 2008-05-02. Strong-Coupling Phases of Frustrated Bosons on a 2-leg Ladder with Ring Exchange. https://doi.org/10.1103/physrevb.78.054520

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