3,745 research outputs found
A strong triangle inequality in hyperbolic geometry
For a triangle in the hyperbolic plane, let denote the
angles opposite the sides , respectively. Also, let be the height of
the altitude to side . Under the assumption that can
be chosen uniformly in the interval and it is given that
holds approximately 79\% of the time. To accomplish this, we prove a
number of theoretical results to make sure that the probability can be computed
to an arbitrary precision, and the error can be bounded
Luttinger theorem for the strongly correlated Fermi liquid of composite fermions
While an ordinary Fermi sea is perturbatively robust to interactions, the
paradigmatic composite-fermion (CF) Fermi sea arises as a non-perturbative
consequence of emergent gauge fields in a system where there was no Fermi sea
to begin with. A mean-field picture suggests two Fermi seas, of composite
fermions made from electrons or holes in the lowest Landau level, which occupy
different areas away from half filling and thus appear to represent distinct
states. We show that in the microscopic theory of composite fermions, which
satisfies particle-hole symmetry in the lowest Landau level to an excellent
degree, the Fermi wave vectors at filling factors and are the
same, and are generally consistent with the experimental findings of Kamburov
{\em et al.} [Phys. Rev. Lett. {\bf 113}, 196801 (2014)]. Our calculations
suggest that the area of the CF Fermi sea may slightly violate the Luttinger
area rule.Comment: 21 pages, 17 figures including supplemental material, published
versio
Comparative analysis of 18S rRNA genes from Myxobolus aeglefini Auerbach, 1906 isolated from cod (Gadus morhua), Plaice (Pleuronectes platessa) and dab (Limanda limanda), using PCR-RFLP
The myxosporean parasite Myxobolus aeglefini is a marine species, which can be found in the cartilage of mainly gadid fish species. The parasite has, however, been recorded in the flatfish plaice (Pleuronectes platessa) and dab (Limanda limanda). It is not clear if isolates from unrelated hosts represent the same species. Therefore a molecular study was conducted to reveal differences at the DNA level between these isolates. PCR was successfully conducted on three different isolates of Myxobolus aeglefini sampled from cod (Gadus morhua), plaice and dab respectively, using 18S rDNA as template. A PCR product of approx. 1600 base pairs was obtained and RFLP (Restriction Fragment Length Polymerase) was conducted on the fragment with the restriction enzymes Hinf I, Msp I and Hae III. No differences between the isolates were found, suggesting that the three isolates represent the same species
Phase Diagram of Fractional Quantum Hall Effect of Composite Fermions in Multi-Component Systems
While the integer quantum Hall effect of composite fermions manifests as the
prominent fractional quantum Hall effect (FQHE) of electrons, the FQHE of
composite fermions produces further, more delicate states, arising from a weak
residual interaction between composite fermions. We study the spin phase
diagram of these states, motivated by the recent experimental observation by
Liu {\em et al.} \cite{Liu14a,Liu14b} of several spin-polarization transitions
at 4/5, 5/7, 6/5, 9/7, 7/9, 8/11 and 10/13 in GaAs systems. We show that the
FQHE of composite fermions is much more prevalent in multicomponent systems,
and consider the feasibility of such states for systems with
components for an SU() symmetric interaction. Our results apply to
GaAs quantum wells, wherein electrons have two components, to AlAs quantum
wells and graphene, wherein electrons have four components (two spins and two
valleys), and to an H-terminated Si(111) surface, which can have six
components. The aim of this article is to provide a fairly comprehensive list
of possible incompressible fractional quantum Hall states of composite
fermions, their SU() spin content, their energies, and their phase
diagram as a function of the generalized "Zeeman" energy. We obtain results at
three levels of approximation: from ground state wave functions of the
composite fermion theory, from composite fermion diagonalization, and, whenever
possible, from exact diagonalization. Effects of finite quantum well thickness
and Landau level mixing are neglected in this study. We compare our theoretical
results with the experiments of Liu {\em et al.} \cite{Liu14a,Liu14b} as well
as of Yeh {\em et al.} \cite{Yeh99} for a two component system.Comment: 29 pages, 6 figure
Phylogeny of Tec Family Kinases: Identification of a Pre-Metazoan Origin of Btk, Bmx, Itk, Tec, Txk and the Btk Regulator SH3BP5
It is generally considered mammals and birds have five Tec family kinases
(TFKs): Btk, Bmx (also known as Etk), Itk, Tec, and Txk (also known as Rlk).
Here, we discuss the domains and their functions and regulation in TFKs. Over
the last few years, a large number of genomes from various phyla have been
sequenced making it possible to study evolutionary relationships at the molecular
and sequence level. Using bioinformatics tools, we for the first time demonstrate
that a TFK ancestor exists in the unicellular choanoflagellate Monosiga brevicollis,
which is the closest known relative to metazoans with a sequenced genome. The
analysis of the genomes for sponges, insects, hagfish, and frogs suggests that these
species encode a single TFK. The insect form has a divergent and unique
N-terminal region. Duplications generating the five members took place prior
to the emergence of vertebrates. Fishes have two or three forms and the platypus,
Ornithorhynchus anatinus, has four (lacks Txk). Thus, not all mammals have all
five TFKs. The single identified TFK in frogs is an ortholog of Tec. Bmx seems to
be unique to mammals and birds. SH3BP5 is a negative regulator of Btk. It is
conserved in choanoflagellates and interestingly exists also in nematodes, which
do not express TFKs, suggesting a broader function in addition to Btk regulation.
The related SH3BP5-like protein is not found in Nematodes
A Rewriting-Logic-Based Technique for Modeling Thermal Systems
This paper presents a rewriting-logic-based modeling and analysis technique
for physical systems, with focus on thermal systems. The contributions of this
paper can be summarized as follows: (i) providing a framework for modeling and
executing physical systems, where both the physical components and their
physical interactions are treated as first-class citizens; (ii) showing how
heat transfer problems in thermal systems can be modeled in Real-Time Maude;
(iii) giving the implementation in Real-Time Maude of a basic numerical
technique for executing continuous behaviors in object-oriented hybrid systems;
and (iv) illustrating these techniques with a set of incremental case studies
using realistic physical parameters, with examples of simulation and model
checking analyses.Comment: In Proceedings RTRTS 2010, arXiv:1009.398
Flavor Alignment via Shining in RS
We present a class of warped extra dimensional models whose flavor violating
interactions are much suppressed compared to the usual anarchic case due to
flavor alignment. Such suppression can be achieved in models where part of the
global flavor symmetry is gauged in the bulk and broken in a controlled manner.
We show that the bulk masses can be aligned with the down type Yukawa couplings
by an appropriate choice of bulk flavon field representations and TeV brane
dynamics. This alignment could reduce the flavor violating effects to levels
which allow for a Kaluza-Klein scale as low as 2-3 TeV, making the model
observable at the LHC. However, the up-type Yukawa couplings on the IR brane,
which are bounded from below by recent bounds on CP violation in the D system,
induce flavor misalignment radiatively. Off-diagonal down-type Yukawa couplings
and kinetic mixings for the down quarks are both consequences of this effect.
These radiative Yukawa corrections can be reduced by raising the flavon VEV on
the IR brane (at the price of some moderate tuning), or by extending the Higgs
sector. The flavor changing effects from the radiatively induced Yukawa mixing
terms are at around the current upper experimental bounds. We also show the
generic bounds on UV-brane induced flavor violating effects, and comment on
possible additional flavor violations from bulk flavor gauge bosons and the
bulk Yukawa scalars.Comment: 28 page
A Flavor Protection for Warped Higgsless Models
We examine various possibilities for realistic 5D higgsless models and
construct a full quark sector featuring next-to-minimal flavor violation (with
an exact bulk SU(2) protecting the first two generations) satisfying
electroweak and flavor constraints. The "new custodially protected
representation" is used for the third generation to protect the light quarks
from flavor violations induced due to the heavy top. A combination of flavor
symmetries, and RS-GIM for the right-handed quarks suppresses flavor-changing
neutral currents below experimental bounds, assuming CKM-type mixing on the UV
brane. In addition to the usual higgsless RS signals, this model predicts an
exotic charge-5/3 quark with mass of about 0.5 TeV which should show up at the
LHC very quickly, as well as nonzero flavor-changing neutral currents which
could be detected in the next generation of flavor experiments. In the course
of our analysis, we also find quantitative estimates for the errors of the
fermion zero mode approximation, which are significant for higgsless-type
models.Comment: 26 pages, 3 figures. v2: References added, typos fixed, corrected C4
bounds (now less severe), slightly extended discussion of result
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