Classical and Quantum Liquids Induced by Quantum Fluctuations

Geometrically frustrated interactions may render classical ground states macroscopically degenerate. The connection between classical and quantum liquids and how the degeneracy is affected by quantum fluctuations is, however, not completely understood. We study a simple model of coupled quantum and...

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Bibliographic Details
Published in:Physical review letters 2019-05, Vol.122 (19), p.197601-197601, Article 197601
Main Authors: Oliveira, Miguel M, Ribeiro, Pedro, Kirchner, Stefan
Format: Article
Language:English
Subjects:
Critical point
Crossovers
Liquids
Phase diagrams
Quantum phenomena
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Summary:Geometrically frustrated interactions may render classical ground states macroscopically degenerate. The connection between classical and quantum liquids and how the degeneracy is affected by quantum fluctuations is, however, not completely understood. We study a simple model of coupled quantum and classical degrees of freedom, the so-called Falicov-Kimball model, on a triangular lattice and away from half-filling. For weak interactions the phase diagram features a charge disordered state down to zero temperature. We provide compelling evidence that this phase is a liquid and show that it is divided by a crossover line that terminates in a quantum critical point. Our results offer a new vantage point to address how quantum liquids can emerge from their classical counterparts.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.122.197601