3,457 research outputs found
Comment on "Density of States and Critical Behavior of the Coulomb Glass"
In a recent numerical investigation of the Coulomb glass, Surer et al. [Phys.
Rev. Lett. 102, 067205 (2009)] concluded that their simulation results are
consistent with the Efros Shklovskii prediction for the density of states in
the three-dimensional case. Here, we show that this statement has no relevance
concerning the problem of the asymptotic behavior in the Coulomb gap since it
is based on unjustified assumptions. Moreover, for the random-displacement
Coulomb glass model, we demonstrate that a part of the density of states data
by Surer et al. erroneously exhibit a broad gap. This is related to the
staggered occupation being instable contrary to their findings.Comment: Submitted to Physical Review Letters, 1 page, 1 figur
Non-ergodic effects in the Coulomb glass: specific heat
We present a numerical method for the investigation of non-ergodic effects in
the Coulomb glass. For that, an almost complete set of low-energy many-particle
states is obtained by a new algorithm. The dynamics of the sample is mapped to
the graph formed by the relevant transitions between these states, that means
by transitions with rates larger than the inverse of the duration of the
measurement. The formation of isolated clusters in the graph indicates
non-ergodicity. We analyze the connectivity of this graph in dependence on
temperature, duration of measurement, degree of disorder, and dimensionality,
studying how non-ergodicity is reflected in the specific heat.Comment: Submited Phys. Rev.
The Optosystem: validation and testing of the high-speed optical-to-electrical conversion system for the readout of the ATLAS ITk Pixel upgrade
After Run III the ATLAS detector will undergo a series of upgrades to cope
with the harsher radiation environment and increased number of proton
interactions in the High Luminosity-LHC. One of the key projects in this suite
of upgrades is the ATLAS Inner Tracker (ITk). The pixel detector of the ITk
must be read out accurately and with extremely high rate. The Optosystem
performs optical-to-electrical conversion of signals from the pixel modules.
This paper presents recent results related to the performance of the data
transmission chain pivoted on the Optoboards and to the design, testing and
production of the Optopanels.Comment: Topical Workshop on Electronics for Particle Physics 2023, 1 October
2023 to 6 October 2023, Geremeas, Sardini
Source of entangled atom pairs on demand, using the Rydberg blockade
Two ultracold atom clouds, each separately in a dipole-blockade regime,
realize a source of entangled atom pairs that can be ejected on demand.
Entanglement generation and ejection is due to resonant dipole-dipole
interactions, while van-der-Waals interactions are predominantly responsible
for the blockade that ensures the ejection of a single atom per cloud. A source
of entangled atoms using these effects can operate with a 10 kHz repetition
rate producing ejected atoms with velocities of about 0.5 m/s.Comment: 7 pages, 4 figure
Rate Dependence and Role of Disorder in Linearly Sheared Two-Dimensional Foams
The shear flow of two dimensional foams is probed as a function of shear rate
and disorder. Disordered foams exhibit strongly rate dependent velocity
profiles, whereas ordered foams show rate independence. Both behaviors are
captured quantitatively in a simple model based on the balance of the
time-averaged drag forces in the foam, which are found to exhibit power-law
scaling with the foam velocity and strain rate. Disorder modifies the scaling
of the averaged inter-bubble drag forces, which in turn causes the observed
rate dependence in disordered foams.Comment: 4 Figures, 4 page
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