13 research outputs found
Pair-wise decoherence in coupled spin qubit networks
Experiments involving phase coherent dynamics of networks of spins, such as
echo experiments, will only work if decoherence can be suppressed. We show
here, by analyzing the particular example of a crystalline network of Fe8
molecules, that most decoherence typically comes from pairwise interactions
(particularly dipolar interactions) between the spins, which cause `correlated
errors'. However at very low T these are strongly suppressed. These results
have important implications for the design of quantum information processing
systems using electronic spins.Comment: 4 pages, 4 figures. Final PRL versio
Towards the solution of the many-electron problem in real materials: Equation of state of the hydrogen chain with state-of-the-art many-body methods
We present numerical results for the equation of state of an infinite chain of hydrogen atoms. A variety of modern many-body methods are employed, with exhaustive cross-checks and validation. Approaches for reaching the continuous space limit and the thermodynamic limit are investigated, proposed, and tested. The detailed comparisons provide a benchmark for assessing the current state of the art in many-body computation, and for the development of new methods. The ground-state energy per atom in the linear chain is accurately determined versus bond length, with a confidence bound given on all uncertainties
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Fermi Blockade of the Strong Electron-Phonon Interaction in Modelled Optimally Doped High Temperature Superconductors
We study how manifestations of strong electron-phonon interaction depend on the carrier concentration by solving the two-dimensional Holstein model for the spin-polarized fermions using an approximation free bold-line diagrammatic Monte Carlo method. We show that the strong electron-phonon interaction, obviously present at very small Fermion concentration, is masked by the Fermi blockade effects and Migdal\u27s theorem to the extent that it manifests itself as moderate one at large carriers densities. Suppression of strong electron-phonon interaction fingerprints is in agreement with experimental observations in doped high temperature superconductors
Dynamic response of the electron gas: Towards the exact exchange-correlation kernel
Precise calculations of dynamics in the homogeneous electron gas (jellium
model) are of fundamental importance for design and characterization of new
materials. We introduce a diagrammatic Monte Carlo technique based on
algorithmic Matsubara integration that allows us to compute frequency and
momentum resolved finite temperature response directly in the real frequency
domain using series of connected Feynman diagrams. The data for charge response
at moderate electron density are used to extract the frequency dependence of
the exchange-correlation kernel at finite momenta and temperature. These
results are as important for development of the time-dependent density
functional theory for materials dynamics as ground state energies are for the
density functional theory.Comment: Main text: 5 pages, 5 figures; Supplemental: 2 pages, 4 figure