9,636 research outputs found
Microscopic dynamics of supercooled liquids from first principles
Glasses are solid materials whose constituent atoms are arranged in a
disordered manner. The transition from a liquid to a glass remains one of the
most poorly understood phenomena in condensed matter physics, and still no
fully microscopic theory exists that can describe the dynamics of supercooled
liquids in a quantitative manner over all relevant time scales. Here we present
such a theoretical framework that yields near-quantitative accuracy for the
time-dependent correlation functions of a supercooled system over a broad
density range. Our approach requires only simple static structural information
as input and is based entirely based on first principles. Owing to this
first-principles nature, the framework offers a unique platform to study the
relation between structure and dynamics in glass-forming matter, and paves the
way towards a systematically correctable and ultimately fully quantitative
theory of microscopic glassy dynamics
Relaxation Patterns in Supercooled Liquids from Generalized Mode-Coupling Theory
The mode-coupling theory of the glass transition treats the dynamics of
supercooled liquids in terms of two-point density correlation functions. Here
we consider a generalized, hierarchical formulation of schematic mode-coupling
equations in which the full basis of multipoint density correlations is taken
into account. By varying the parameters that control the effective
contributions of higher-order correlations, we show that infinite hierarchies
can give rise to both sharp and avoided glass transitions. Moreover, small
changes in the form of the coefficients result in different scaling behaviors
of the structural relaxation time, providing a means to tune the fragility in
glass-forming materials. This demonstrates that the infinite-order construct of
generalized mode-coupling theory constitutes a powerful and unifying framework
for kinetic theories of the glass transition
A method for precise charge reconstruction with pixel detectors using binary hit information
A method is presented to precisely reconstruct charge spectra with pixel
detectors using binary hit information of individual pixels. The method is
independent of the charge information provided by the readout circuitry and has
a resolution mainly limited by the electronic noise. It relies on the ability
to change the detection threshold in small steps while counting hits from a
particle source. The errors are addressed and the performance of the method is
shown based on measurements with the ATLAS pixel chip FE-I4 bump bonded to a
230 {\mu}m 3D-silicon sensor. Charge spectra from radioactive sources and from
electron beams are presented serving as examples. It is demonstrated that a
charge resolution ({\sigma}<200 e) close to the electronic noise of the ATLAS
FE-I4 pixel chip can be achieved
Characterization and Verification Environment for the RD53A Pixel Readout Chip in 65 nm CMOS
The RD53 collaboration is currently designing a large scale prototype pixel
readout chip in 65 nm CMOS technology for the phase 2 upgrades at the HL-LHC.
The RD53A chip will be available by the end of the year 2017 and will be
extensively tested to confirm if the circuit and the architecture make a solid
foundation for the final pixel readout chips for the experiments at the HL-LHC.
A test and data acquisition system for the RD53A chip is currently under
development to perform single-chip and multi-chip module measurements. In
addition, the verification of the RD53A design is performed in a dedicated
simulation environment. The concept and the implementation of the test and data
acquisition system and the simulation environment, which are based on a modular
data acquisition and system testing framework, are presented in this work
Kaon electromagnetic production: constraints set by new data
The CLAS data on the photo-production of K+ off the proton are utilised to
study reaction mechanism of the process in frame of the isobaric approach. The
missing D13 resonance is shown to be important for successful description of
the data in the whole kinematical region. Constructed models provide
satisfactory predictions for the process.Comment: 4 pages, 4 figures, contribution to the VIII International Conference
on Hypernuclear & Strange Particle Physics, Jefferson Lab, Virginia, U.S.A.,
October 14-18, 200
Mechanisms Affecting Recruitment of Yellow Perch in Lake Michigan
Report issued on: August 2001INHS Technical Report prepared for Great Lakes Fishery Trus
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