3,127 research outputs found
Evidence of Luttinger liquid behavior in one-dimensional dipolar quantum gases
The ground state and structure of a one-dimensional Bose gas with dipolar
repulsions is investigated at zero temperature by a combined Reptation Quantum
Monte Carlo (RQMC) and bosonization approach. A non trivial Luttinger-liquid
behavior emerges in a wide range of intermediate densities, evolving into a
Tonks-Girardeau gas at low density and into a classical quasi-ordered state at
high density. The density dependence of the Luttinger exponent is extracted
from the numerical data, providing analytical predictions for observable
quantities, such as the structure factor and the momentum distribution. We
discuss the accessibility of such predictions in current experiments with
ultracold atomic and molecular gases.Comment: 4 pages, 3 EPS figures, Revtex
The spin-incoherent Luttinger liquid
In contrast to the well known Fermi liquid theory of three dimensions,
interacting one-dimensional and quasi one-dimensional systems of fermions are
described at low energy by an effective theory known as Luttinger liquid
theory. This theory is expressed in terms of collective many-body excitations
that show exotic behavior such as spin-charge separation. Luttinger liquid
theory is commonly applied on the premise that "low energy" describes both the
spin and charge sectors. However, when the interactions in the system are very
strong, as they typically are at low particle densities, the ratio of spin to
charge energy may become exponentially small. It is then possible at very low
temperatures for the energy to be low compared to the characteristic charge
energy, but still high compared to the characteristic spin energy. This energy
window of near ground-state charge degrees of freedom, but highly thermally
excited spin degrees of freedom is called a spin-incoherent Luttinger liquid.
The spin-incoherent Luttinger liquid exhibits a higher degree universality than
the Luttinger liquid and its properties are qualitatively distinct. In this
colloquium I detail some of the recent theoretical developments in the field
and describe experimental indications of such a regime in gated semiconductor
quantum wires.Comment: 21 pages, 18 figures. Updated references, corrected typo in Eq.(20)
in journal versio
A New Analysis Method for Simulations Using Node Categorizations
Most research concerning the influence of network structure on phenomena
taking place on the network focus on relationships between global statistics of
the network structure and characteristic properties of those phenomena, even
though local structure has a significant effect on the dynamics of some
phenomena. In the present paper, we propose a new analysis method for phenomena
on networks based on a categorization of nodes. First, local statistics such as
the average path length and the clustering coefficient for a node are
calculated and assigned to the respective node. Then, the nodes are categorized
using the self-organizing map (SOM) algorithm. Characteristic properties of the
phenomena of interest are visualized for each category of nodes. The validity
of our method is demonstrated using the results of two simulation models. The
proposed method is useful as a research tool to understand the behavior of
networks, in particular, for the large-scale networks that existing
visualization techniques cannot work well.Comment: 9 pages, 8 figures. This paper will be published in Social Network
Analysis and Mining(www.springerlink.com
Probing Lepton Flavor Violation at Future Colliders
Supersymmetric theories with significant lepton flavor violation have
and nearly degenerate. In this case, pair production
of and at LEPII and at
the Next Linear Collider leads to the phenomenon of slepton oscillations, which
is analogous to neutrino oscillations. The reach in and gives a probe of lepton flavor violation which is significantly more
powerful than the current bounds from rare processes, such as . Polarizable beams and the mode at the NLC are found to
be promising options.Comment: 10 pages, 3 figures, RevTeX, minor corrections, published versio
First-Principles Study on Peierls Instability in Infinite Single-Row Al Wires
We present the relation between the atomic and spin-electronic structures of
infinite single-row atomic wires made of Al atoms during their elongation using
first-principles molecular-dynamics simulations. Our study reveals that the
Peierls transition indeed occurs in the wire with magnetic ordering: it
ruptures to form a trimerized structure with antiferromagnetic ordering and
changes from a conductor to an insulator just before forming a linear wire of
equally-spaced atoms. The formation of the trimerized wire is discussed in
terms of the behavior of the -symmetry bands of the Al wire.Comment: 10 pages, 4 figure
Global monopole solutions in Horava gravity
In Horava's theory of gravity coupled to a global monopole source, we seek
for static, spherically symmetric spacetime solutions for general values of
. We obtain the explicit solutions with deficit solid angles, in the
IR modified Horava gravity model, at the IR fixed point and at the
conformal point . For the other values of we also
find special solutions to the inhomogenous equation of the gravity model with
detailed balance, and we discuss an possibility of astrophysical applications
of the solution that has a deficit angle for a finite range.Comment: 7 pages, added reference
Oceanic spawning ecology of freshwater eels in the western North Pacific
The natural reproductive ecology of freshwater eels remained a mystery even after some of their offshore spawning areas were discovered approximately 100 years ago. In this study, we investigate the spawning ecology of freshwater eels for the first time using collections of eggs, larvae and spawning-condition adults of two species in their shared spawning area in the Pacific. Ovaries of female Japanese eel and giant mottled eel adults were polycyclic, suggesting that freshwater eels can spawn more than once during a spawning season. The first collection of Japanese eel eggs near the West Mariana Ridge where adults and newly hatched larvae were also caught shows that spawning occurs during new moon periods throughout the spawning season. The depths where adults and newly hatched larvae were captured indicate that spawning occurs in shallower layers of 150–200 m and not at great depths. This type of spawning may reduce predation and facilitate reproductive success
Confronting the Minimal Supersymmetric Standard Model with the Study of Scalar Leptons at Future Linear e+e- Colliders
Sleptons can easily be found at future linear e+e- colliders if kinematically
accessible. Measurements of their masses and decay distributions would then
determine MSSM parameters. This paper presents a detailed MC study of the
production and decay of the lighter scalar tau lepton, stau1. We found that
mstau1 and the left-right mixing angle of stau would be measured within an
error of a few percent. tanbeta is determinable in some region of the parameter
space through simultaneous studies of stau1-and selectron-pair production: the
polarization measurement of the tau leptons from stau1 decays and the M1, mchi1
determination using selectron pair production and decay. We also point out the
possibility to determine bino-selectron-e coupling through the measurement of
the angular distribution of the selectron-pair production. The error on the
coupling is expected to be comparable to its typical SUSY radiative correction,
which is proportional to log(msquark/mslepton). The radiative correction
affects M1 and tanbeta determination, necessitating the full 1-loop radiative
correction to the selectron production processes. The implication of these
measurements of the MSSM parameters on selecting models of the origin of
supersymmetry breaking is also discussed.Comment: 35 pages. REVTEX(gzip compressed and uuencoded). Figure are not
included. Text and 15 Figures are available at
http://jlcux1.kek.jp/subg/susy/index-e.html#librar
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