3,938 research outputs found
Dynamics of entanglement in the transverse Ising model
We study the evolution of nearest-neighbor entanglement in the one
dimensional Ising model with an external transverse field. The system is
initialized as the so called "thermal ground state" of the pure Ising model. We
analyze properties of generation of entanglement for different regions of
external transverse fields. We find that the derivation of the time at which
the entanglement reaches its first maximum with respect to the reciprocal
transverse field has a minimum at the critical point. This is a new indicator
of quantum phase transition.Comment: To be published in PR
Tuning orbital-selective correlation effects in superconducting RbFeSeS
We report on terahertz time-domain spectroscopy on superconducting and
metallic iron chalcogenides RbFeSeS. The
superconducting transition is reduced from 32 K () to 22 K
(), and finally suppressed () by isoelectronic substitution of Se
with S. Dielectric constant and optical conductivity exhibit a
metal-to-insulator transition associated with an orbital-selective Mott phase.
This orbital-selective Mott transition appears at higher temperature
with increasing sulfur content, identifying sulfur substitution as an efficient
parameter to tune orbital-dependent correlation effects in iron-chalcogenide
superconductors. The reduced correlations of the charge carriers can
account for the suppression of the superconductivity and the pseudogap-like
feature between and that was observed for .Comment: 6 pages, 4 figure
A molecular dynamics simulation of DNA damage induction by ionizing radiation
We present a multi-scale simulation of early stage of DNA damages by the
indirect action of hydroxyl (OH) free radicals generated by electrons
and protons. The computational method comprises of interfacing the Geant4-DNA
Monte Carlo with the ReaxFF molecular dynamics software. A clustering method
was employed to map the coordinates of OH-radicals extracted from the
ionization track-structures onto nano-meter simulation voxels filled with DNA
and water molecules. The molecular dynamics simulation provides the time
evolution and chemical reactions in individual simulation voxels as well as the
energy-landscape accounted for the DNA-OH chemical reaction that is
essential for the first principle enumeration of hydrogen abstractions,
chemical bond breaks, and DNA-lesions induced by collection of ions in clusters
less than the critical dimension which is approximately 2-3 \AA. We show that
the formation of broken bonds leads to DNA base and backbone damages that
collectively propagate to DNA single and double strand breaks. For illustration
of the methodology, we focused on particles with initial energy of 1 MeV. Our
studies reveal a qualitative difference in DNA damage induced by low energy
electrons and protons. Electrons mainly generate small pockets of
OH-radicals, randomly dispersed in the cell volume. In contrast,
protons generate larger clusters along a straight-line parallel to the
direction of the particle. The ratio of the total DNA double strand breaks
induced by a single proton and electron track is determined to be 4
in the linear scaling limit. The tool developed in this work can be used in the
future to investigate the relative biological effectiveness of light and heavy
ions that are used in radiotherapy.Comment: 7 pages, 7 figures, accepted for publication in Physics in Medicine
and Biolog
d-wave Holographic Superconductor Vortex Lattice and Non-Abelian Holographic Superconductor Droplet
A d-wave holographic superconductor is studied under a constant magnetic
field by perturbation method, we obtain both droplet and triangular vortex
lattice solution. The results are the same as the s-wave holographic
superconductor. The non-Abelian holographic superconductor with -wave
background is also studied under magnetic field, unlike the d-wave and s-wave
models, we find that the non-Abelian model has only droplet solution.Comment: Version2, 12 pages,2 figures. Accepted by PR
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