865 research outputs found
Thermal conductivity of the one-dimensional Fermi-Hubbard model
We study the thermal conductivity of the one-dimensional Fermi-Hubbard model
at finite temperature using a density matrix renormalization group approach.
The integrability of this model gives rise to ballistic thermal transport. We
calculate the temperature dependence of the thermal Drude weight at half
filling for various interactions and moreover, we compute its filling
dependence at infinite temperature. The finite-frequency contributions
originating from the fact that the energy current is not a conserved quantity
are investigated as well. We report evidence that breaking the integrability
through a nearest-neighbor interaction leads to vanishing Drude weights and
diffusive energy transport. Moreover, we demonstrate that energy spreads
ballistically in local quenches with initially inhomogeneous energy density
profiles in the integrable case. We discuss the relevance of our results for
thermalization in ultra-cold quantum gas experiments and for transport
measurements with quasi-one dimensional materials
Comment on "Anomalous Thermal Conductivity of Frustrated Heisenberg Spin Chains and Ladders"
In a recent letter [Phys. Rev. Lett. 89, 156603 (2002); cond-mat/0201300],
Alvarez and Gros have numerically analyzed the Drude weight for thermal
transport in spin ladders and frustrated chains of up to 14 sites and have
proposed that it remains finite in the thermodynamic limit. In this comment, we
argue that this conclusion cannot be sustained if the finite-size analysis is
taken to larger system sizes.Comment: One page REVTeX4, 1 figure. Published version (minor changes
Magnetic heat conductivity in : linear temperature dependence
We present experimental results for the thermal conductivity of the
pseudo 2-leg ladder material . The strong buckling of the ladder
rungs renders this material a good approximation to a Heisenberg-chain.
Despite a strong suppression of the thermal conductivity of this material in
all crystal directions due to inherent disorder, we find a dominant magnetic
contribution along the chain direction.
is \textit{linear} in temperature, resembling the
low-temperature limit of the thermal Drude weight of the
Heisenberg chain. The comparison of and
yields a magnetic mean free path of \AA, in good agreement with magnetic measurements.Comment: appears in PR
- …