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Abstract
The "sign problem" (SP) is a fundamental limitation to simulations of strongly correlated matter. It is often argued that the SP is not intrinsic to the physics of particular Hamiltonians because its behavior can be influenced by the choice of algorithm. By contrast, we show that the SP in determinant quantum Monte Carlo (QMC) is quantitatively linked to quantum critical behavior. We demonstrate this through simulations of several models with critical properties that are relatively well understood. We propose a reinterpretation of the low average sign for the Hubbard model on the square lattice away from half filling in terms of the onset of pseudogap behavior and exotic superconductivity. Our study charts a path for exploiting the average sign in QMC simulations to understand quantum critical behavior.
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Affiliation(s)
- R Mondaini
- Beijing Computational Science Research Center, Beijing 100193, China
| | - S Tarat
- Beijing Computational Science Research Center, Beijing 100193, China
| | - R T Scalettar
- Department of Physics, University of California, Davis, CA 95616, USA
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Patel ND, Mukherjee A, Kaushal N, Moreo A, Dagotto E. Non-Fermi Liquid Behavior and Continuously Tunable Resistivity Exponents in the Anderson-Hubbard Model at Finite Temperature. PHYSICAL REVIEW LETTERS 2017; 119:086601. [PMID: 28952753 DOI: 10.1103/physrevlett.119.086601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Indexed: 06/07/2023]
Abstract
We employ a recently developed computational many-body technique to study for the first time the half-filled Anderson-Hubbard model at finite temperature and arbitrary correlation U and disorder V strengths. Interestingly, the narrow zero temperature metallic range induced by disorder from the Mott insulator expands with increasing temperature in a manner resembling a quantum critical point. Our study of the resistivity temperature scaling T^{α} for this metal reveals non-Fermi liquid characteristics. Moreover, a continuous dependence of α on U and V from linear to nearly quadratic is observed. We argue that these exotic results arise from a systematic change with U and V of the "effective" disorder, a combination of quenched disorder and intrinsic localized spins.
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Affiliation(s)
- Niravkumar D Patel
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Anamitra Mukherjee
- School of Physical Sciences, National Institute of Science Education and Research, HBNI, Jatni 752050, India
| | - Nitin Kaushal
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Adriana Moreo
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Elbio Dagotto
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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3
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Paiva T, Khatami E, Yang S, Rousseau V, Jarrell M, Moreno J, Hulet RG, Scalettar RT. Cooling Atomic Gases With Disorder. PHYSICAL REVIEW LETTERS 2015; 115:240402. [PMID: 26705614 DOI: 10.1103/physrevlett.115.240402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Indexed: 06/05/2023]
Abstract
Cold atomic gases have proven capable of emulating a number of fundamental condensed matter phenomena including Bose-Einstein condensation, the Mott transition, Fulde-Ferrell-Larkin-Ovchinnikov pairing, and the quantum Hall effect. Cooling to a low enough temperature to explore magnetism and exotic superconductivity in lattices of fermionic atoms remains a challenge. We propose a method to produce a low temperature gas by preparing it in a disordered potential and following a constant entropy trajectory to deliver the gas into a nondisordered state which exhibits these incompletely understood phases. We show, using quantum Monte Carlo simulations, that we can approach the Néel temperature of the three-dimensional Hubbard model for experimentally achievable parameters. Recent experimental estimates suggest the randomness required lies in a regime where atom transport and equilibration are still robust.
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Affiliation(s)
- Thereza Paiva
- Departamento de Física dos Sólidos, Instituto de Física, Universidade Federal do Rio de Janeiro, 21945-970 Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ehsan Khatami
- Department of Physics, San Jose State University, San Jose, California 95192, USA
| | - Shuxiang Yang
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Valéry Rousseau
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Mark Jarrell
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Juana Moreno
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Randall G Hulet
- Department of Physics and Astronomy and Rice Quantum Institute, Rice University, Houston, Texas 77005, USA
| | - Richard T Scalettar
- Department of Physics, University of California, Davis, California 95616, USA
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