1,963 research outputs found
Dynamical properties of S=1 bond-alternating Heisenberg chains in transverse magnetic fields
We calculate dynamical structure factors of the S=1 bond-alternating
Heisenberg chain with a single-ion anisotropy in transverse magnetic fields,
using a continued fraction method based on the Lanczos algorithm. In the
Haldane-gap phase and the dimer phase, dynamical structure factors show
characteristic field dependence. Possible interpretations are discussed. The
numerical results are in qualitative agreement with recent results for
inelastic neutron-scattering experiments on the S=1 bond-alternating
Heisenberg-chain compound and the
S=1 Haldane-gap compound in
transverse magnetic fields.Comment: 7 pages, 6 figure
SoK: Design Tools for Side-Channel-Aware Implementations
Side-channel attacks that leak sensitive information through a computing
device's interaction with its physical environment have proven to be a severe
threat to devices' security, particularly when adversaries have unfettered
physical access to the device. Traditional approaches for leakage detection
measure the physical properties of the device. Hence, they cannot be used
during the design process and fail to provide root cause analysis. An
alternative approach that is gaining traction is to automate leakage detection
by modeling the device. The demand to understand the scope, benefits, and
limitations of the proposed tools intensifies with the increase in the number
of proposals.
In this SoK, we classify approaches to automated leakage detection based on
the model's source of truth. We classify the existing tools on two main
parameters: whether the model includes measurements from a concrete device and
the abstraction level of the device specification used for constructing the
model. We survey the proposed tools to determine the current knowledge level
across the domain and identify open problems. In particular, we highlight the
absence of evaluation methodologies and metrics that would compare proposals'
effectiveness from across the domain. We believe that our results help
practitioners who want to use automated leakage detection and researchers
interested in advancing the knowledge and improving automated leakage
detection
First ring contraction-desulfurization of 1-(arylcarbonyl)pyrido[2,1-c]-1,4-thiazines to 1-(arylcarbonyl)indolizines and its application to 3-arylthieno[3,2-a]indolizine synthesis
The ring contraction-desulfurization route from transient 1-(arylcarbonyl)pyridol2,1-c]-1,4-thiazine intermediates, generated in situ from the treatment of the corresponding pyridinium salts with a base and then a dehydrogenation agent, to 1-(arylcarbonyl)indolizines was first observed. By using this route three 1-arylcarbonyl-6,8-dimethylindolizines having the protected 2-thiol group were prepared and their transformation to 2-acyl-3-arylthieno[3,2-a]indolizine derivatives were performed in good yields.ArticleHETEROCYCLES. 74: 521-532 (2007)journal articl
Technique for bulk Fermiology by photoemission applied to layered ruthenates
We report the Fermi surfaces of the superconductor Sr2RuO4 and the
non-superconductor Sr1.8Ca0.2RuO4 probed by bulk-sensitive high-energy
angle-resolved photoemission. It is found that there is one square-shaped
hole-like, one square-shaped electron-like and one circle-shaped electron-like
Fermi surface in both compounds. These results provide direct evidence for
nesting instability giving rise to magnetic fluctuations. Our study clarifies
that the electron correlation effects are changed with composition depending on
the individual band.Comment: 5 pages, 3 figures including 2 color figure
Tomonaga-Luttinger Liquid in a Quasi-One-Dimensional S=1 Antiferromagnet Observed by the Specific Heat
Specific heat experiments on single crystals of the S=1 quasi-one-dimensional
bond-alternating antiferromagnet Ni(C_9H_24N_4)(NO_2)ClO_4, alias NTENP, have
been performed in magnetic fields applied both parallel and perpendicular to
the spin chains. We have found for the parallel field configuration that the
magnetic specific heat (C_mag) is proportional to temperature (T) above a
critical field H_c, at which the energy gap vanishes, in a temperature region
above that of the long-range ordered state. The ratio C_mag/T increases as the
magnetic field approaches H_c from above. The data are in good quantitative
agreement with the prediction of the c=1 conformal field theory in conjunction
with the velocity of the excitations calculated by a numerical diagonalization,
providing a conclusive evidence for a Tomonaga-Luttinger liquid.Comment: 4 pages, 4 postscript figure
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