### Abstract

Original language | English |
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Pages (from-to) | 999-1014 |

Number of pages | 16 |

Journal | International journal of modern physics / B |

Volume | 05 |

Issue number | 06n07 |

DOIs | |

Publication status | Published - 1 Apr 1991 |

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*International journal of modern physics / B*,

*05*(06n07), 999-1014. https://doi.org/10.1142/S0217979291000523

**The hubbard model: from small to large u.** / Baeriswyl, Dionys; Von Der Linden, Wolfgang.

Research output: Contribution to journal › Article › Research › peer-review

*International journal of modern physics / B*, vol. 05, no. 06n07, pp. 999-1014. https://doi.org/10.1142/S0217979291000523

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TY - JOUR

T1 - The hubbard model: from small to large u

AU - Baeriswyl, Dionys

AU - Von Der Linden, Wolfgang

PY - 1991/4/1

Y1 - 1991/4/1

N2 - The Hubbard model is investigated starting from both the small and large U limits. This allows one to derive an interpolation formula for the double occupancy at half-filling for dimensionalities d = 1, 2, 3. It shows a smooth behavior as a function of U and tends to zero only for U → ∞. A quantity that probes more sensitively the nature of the ground state is the momentum distribution function n(k). At half filling n(k) is smooth at kF both for d = 1 and d = 2, at least for not too small values of U. In one dimension for all other band fillings the slope of n(k) has a power-law singularity at kF with an exponent α increasing steadily from zero at U = 0 to 1/8 for U → ∞; the system is a "marginal Fermi liquid". A similar behavior may occur close to half-filling for d = 2, but for small densities one expects the usual step function of a normal Fermi liquid.

AB - The Hubbard model is investigated starting from both the small and large U limits. This allows one to derive an interpolation formula for the double occupancy at half-filling for dimensionalities d = 1, 2, 3. It shows a smooth behavior as a function of U and tends to zero only for U → ∞. A quantity that probes more sensitively the nature of the ground state is the momentum distribution function n(k). At half filling n(k) is smooth at kF both for d = 1 and d = 2, at least for not too small values of U. In one dimension for all other band fillings the slope of n(k) has a power-law singularity at kF with an exponent α increasing steadily from zero at U = 0 to 1/8 for U → ∞; the system is a "marginal Fermi liquid". A similar behavior may occur close to half-filling for d = 2, but for small densities one expects the usual step function of a normal Fermi liquid.

U2 - 10.1142/S0217979291000523

DO - 10.1142/S0217979291000523

M3 - Article

VL - 05

SP - 999

EP - 1014

JO - International journal of modern physics / B

JF - International journal of modern physics / B

SN - 0217-9792

IS - 06n07

ER -