23,344 research outputs found
Heavy Ion Physics at LHC
The study of heavy ion interactions constitutes an important part of the
experimental program outlined for the Large Hadron Collider under construction
at CERN and expected to be operational by 2006. ALICE is the single detector
having the capabilities to explore at the same time most of the characteristics
of high energy heavy ion interactions. Specific studies of jet quenching and
quarkonia production, essentially related to detection are also planned
by CMS.Comment: 5 pages, 1 figure (in eps) talk given at XXXI International Symposium
on Multiparticle Dynamics, Sep. 1-7, 2001, Datong China URL
http://ismd31.ccnu.edu.cn
Should We Be Concerned about the Distribution of Literacy across Households? An Axiomatic Investigation
This paper proposes a class of literacymeasures that takes into account the externality generated by the presence of literates in the household. It is claimed that such externality is increasing in the number of literates in the household, has characteristics of rivalry in consumption, and therefore is a function of the distribution of literates and illiterates in the household. The measure is given a full axiomatic characterization, and it is shown that its use may reverse the ranking of geographical areas obtained by using other literacy measures.
Ab-initio Phonon Calculations for the layered compound TiOCl
We present first-principles frozen-phonon calculations for the three
Raman-active modes in the spin-1/2 layered TiOCl system within two
different well-known approaches: the local density approximation (LDA) and the
so-called LDA+U approximation. We observe that the inclusion of electron
correlation in a mean-field level as implemented in the LDA+U leads to a better
overall agreement with experimental results. We also discuss the implications
of the two approaches on the physics of TiOCl.Comment: Phys. Rev. B (Rapid Comm.) (in Press
Magnon splitting induced by charge ordering in NaV_2O_5
We consider the effects of charge ordering in NaV_2O_5 (below T_SP) on the
exchange constants and on the magnon dispersion. We show that the
experimentally observed splitting of the magnon branches along the a direction
is induced by charge ordering. We find that one can distinguish between the
proposed 'zig-zag' and 'in-line' patterns of charge ordering. Only the zig-zag
ordering is consistent with the experimental results regarding (i) the unusual
intensity modulation observed in magnetic neutron scattering, (ii) the
reduction in the intra-ladder exchange constant below T_SP, and (iii) the
magnon dispersion along a. We estimate the inter-ladder exchange constant to be
1.01meV=11.7K for T>T_SP.Comment: final version for PR
An Accurate and Efficient Analysis of a MBSFN Network
A new accurate analysis is presented for an OFDM-based multicast-broadcast
single-frequency network (MBSFN). The topology of the network is modeled by a
constrained random spatial model involving a fixed number of base stations
placed over a finite area with a minimum separation. The analysis is driven by
a new closed-form expression for the conditional outage probability at each
location of the network, where the conditioning is with respect to the network
realization. The analysis accounts for the diversity combining of signals
transmitted by different base stations of a given MBSFN area, and also accounts
for the interference caused by the base stations of other MBSFN areas. The
analysis features a flexible channel model, accounting for path loss, Nakagami
fading, and correlated shadowing. The analysis is used to investigate the
influence of the minimum base-station separation and provides insight regarding
the optimal size of the MBSFN areas. In order to highlight the percentage of
the network that will fail to successfully receive the broadcast, the area
below an outage threshold (ABOT) is here used and defined as the fraction of
the network that provides an outage probability (averaged over the fading) that
meets a threshold.Comment: 5 pages, 4 figures, IEEE International Conference on Acoustics,
Speech and Signal Processing (ICASSP), 2014, to appea
Comparative study between two quantum spin systems KCuCl and TlCuCl
We have performed an {\it ab initio} study of the electronic structure of two
isostructural quantum spin systems, KCuCl and TlCuCl, which have
recently attracted much attention due to their unconventional magnetic
properties. Our first-principles analysis shows unambiguously the role of Tl,
as opposed to structural differences between the two compounds, in making
TlCuCl a {\it strongly} coupled s=1/2 dimer system compared to
KCuCl which shows a {\it weakly} coupled s=1/2 dimer behavior. Good
agreement with the existing analysis of inelastic neutron scattering results
has been observed.Comment: minor changes in text with additional references; in EPL forma
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