4,786 research outputs found
Quantum Monte Carlo study of confined fermions in one-dimensional optical lattices
Using quantum Monte Carlo (QMC) simulations we study the ground-state
properties of the one-dimensional fermionic Hubbard model in traps with an
underlying lattice. Since due to the confining potential the density is space
dependent, Mott-insulating domains always coexist with metallic regions, such
that global quantities are not appropriate to describe the system. We define a
local compressibility that characterizes the Mott-insulating regions and
analyze other local quantities. It is shown that the momentum distribution
function, a quantity that is commonly considered in experiments, fails in
giving a clear signal of the Mott-insulator transition. Furthermore, we analyze
a mean-field approach to these systems and compare it with the numerically
exact QMC results. Finally, we determine a generic form for the phase diagram
that allows us to predict the phases to be observed in the experiments.Comment: RevTex file, 13 pages, 19 figures, published versio
Ground-state properties of hard-core bosons confined on one-dimensional optical lattices
We study the ground-state properties of hard-core bosons trapped by arbitrary
confining potentials on one-dimensional optical lattices. A recently developed
exact approach based on the Jordan-Wigner transformation is used. We analyze
the large distance behavior of the one-particle density matrix, the momentum
distribution function, and the lowest natural orbitals. In addition, the
low-density limit in the lattice is studied systematically, and the results
obtained compared with the ones known for the hard-core boson gas without the
lattice.Comment: RevTex file, 14 pages, 22 figures, published versio
A case of subfertile cow with structural abnormalities of the X-chromosome
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Mott Domains of Bosons Confined on Optical Lattices
In the absence of a confining potential, the boson Hubbard model in its
ground state is known to exhibit a superfluid to Mott insulator quantum phase
transition at commensurate fillings and strong on-site repulsion. In this
paper, we use quantum Monte Carlo simulations to study the ground state of the
one dimensional bosonic Hubbard model in a trap. We show that some, but not
all, aspects of the Mott insulating phase persist when a confining potential is
present. The Mott behavior is present for a continuous range of incommensurate
fillings, a very different situation from the unconfined case. Furthermore the
establishment of the Mott phase does not proceed via a quantum phase transition
in the traditional sense. These observations have important implications for
the interpretation of experimental results for atoms trapped on optical
lattices. Initial results show that, qualitatively, the same results persist in
higher dimensions.Comment: Revtex file, five figures, include
Robertsonian chromosome polymorphism found in a local herd of the Japanese Black cattle
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Formation of off-centered double-walled carbon nanotubes exhibiting wide interlayer spacing from bi-cables
ArticleChemical Physics Letters. 432(1-3):240-244 (2006)journal articl
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