54,908 research outputs found
On the Origin of the Non-Fermi Liquid Behavior of SrRuO_{3}
Motivated by the unusual features observed in the transport properties of the
ferromagnetic "bad metal" , we construct a model incorporating
essential features of the realistic structure of this nearly cubic material. In
particular, we show how the orbital {\it orientation} in the perfectly
cubic structure determines the peculiar structure of the hybridization matrix,
and demonstrate how the local non-Fermi liquid features arise when interactions
are switched on. we discuss the effect of the slight deviation from the cubic
structure (at low-) qualitatively. The model provides a consistent
explanation of the features observed recently in the optical response of
.Comment: 4 pages. Submitted to Physical Review Letter
New mechanism of membrane fusion
We have carried out Monte Carlo simulation of the fusion of bilayers of
single chain amphiphiles which show phase behavior similar to that of
biological lipids. The fusion mechanism we observe is very different from the
``stalk'' hypothesis. Stalks do form on the first stage of fusion, but they do
not grow radially to form a hemifused state. Instead, stalk formation
destabilizes the membranes and results in hole formation in the vicinity of the
stalks. When holes in each bilayer nucleate spontaneously next to the same
stalk, an incomplete fusion pore is formed. The fusion process is completed by
propagation of the initial connection, the stalk, along the edges of the
aligned holes.Comment: 4 pages, 3 figure
Orbital Switching and the First-Order Insulator-Metal Transition in Paramagnetic V_2O_3
The first-order metal-insulator transition (MIT) in paramagnetic
is studied within the ab-initio scheme LDA+DMFT, which merges the local density
approximation (LDA) with dynamical mean field theory (DMFT). With a fixed value
of the Coulomb , we show how the abrupt pressure driven MIT is
understood in a new picture: pressure-induced decrease of the trigonal
distortion within the strong correlation scenario (which is not obtained within
LDA). We find good quantitative agreement with switch of the orbital
occupation of and the spin state S=1
across the MIT, thermodynamics and resistivity, and the
one-electron spectral function, within this new scenario.Comment: 4 pages, 4 figures, submitted to PR
Insulator-Metal transition in the Doped 3d1 Transition Metal Oxide LaTiO3
The doping induced insulator-metal transition in is
studied using the ab-initio LDA+DMFT method. Combining the LDA bandstructure
for the actual, distorted structure found recently with multi-orbital DMFT to
treat electronic correlations, we find: ferro-orbital order in the Mott
insulating state without orbital degeneracy, a continuous filling
induced transition to the paramagnetic metal (PM) with , and
excellent quantitative agreement with published photoemission data for the case
of 6% doping. Our results imply that this system can be described as a
Mott-Hubbard system without orbital (liquid) degeneracy.Comment: 4 pages, 3 figures, submitted to PR
Benchmarking the noise sensitivity of different parametric two-qubit gates in a single superconducting quantum computing platform
The possibility to utilize different types of two-qubit gates on a single
quantum computing platform adds flexibility in the decomposition of quantum
algorithms. A larger hardware-native gate set may decrease the number of
required gates, provided that all gates are realized with high fidelity. Here,
we benchmark both controlled-Z (CZ) and exchange-type (iSWAP) gates using a
parametrically driven tunable coupler that mediates the interaction between two
superconducting qubits. Using randomized benchmarking protocols we estimate an
error per gate of and fidelity for the CZ and the
iSWAP gate, respectively. We argue that spurious -type couplings are the
dominant error source for the iSWAP gate, and that phase stability of all
microwave drives is of utmost importance. Such differences in the achievable
fidelities for different two-qubit gates have to be taken into account when
mapping quantum algorithms to real hardware.Comment: 24 pages, including supplementary informatio
- …