2,175 research outputs found
Chiral Generations on Intersecting 5-branes in Heterotic String Theory
We show that there exist two 27 and one 27 bar of E6, net one D=4, N=1 chiral
matter supermultiplet as zero modes localized on the intersection of two
5-branes in the E8 x E8 heterotic string theory. The smeared intersecting
5-brane solution is used via the standard embedding to construct a heterotic
background, which provides, after a compactification of some of the transverse
dimensions, a five-dimensional Randall-Sundrum II like brane-world set-up in
heterotic string theory. As a by-product, we present a new proof of anomaly
cancellation between those from the chiral matter and the anomaly inflow onto
the brane without small instanton.Comment: 26 pages, 5 figures; references added, typo correcte
Holographic Penta and Hepta Quark State in Confining Gauge Theories
We study a new embedding solutions of D5 brane in an asymptotic
AdS space-time, which is dual to a confining gauge
theory. The D5 brane is wrapped on as in the case of the vertex of
holographic baryon. However, the solution given here is different from the
usual baryon vertex in the point that it couples to -anti-quarks and
quarks on the opposite two points of , the north and south poles,
respectively. The total quark number of this state is preserved as when
minus one is assigned to anti-quark, then it forms a color singlet like the
baryon. However, this includes anti-quarks and quarks, whose number is larger
than that of the baryon. When we set as , we find the so called penta
and hepta-quark states. We study the dynamical properties of these states by
solving the vertex and string configurations for such states. The mass spectra
of these states and the tension of the stretched vertex are estimated, and they
are compared with that of the baryon.Comment: 24 pages, 6 figure
Thermodynamic Properties of Holographic Multiquark and the Multiquark Star
We study thermodynamic properties of the multiquark nuclear matter. The
dependence of the equation of state on the colour charges is explored both
analytically and numerically in the limits where the baryon density is small
and large at fixed temperature between the gluon deconfinement and chiral
symmetry restoration. The gravitational stability of the hypothetical
multiquark stars are discussed using the Tolman-Oppenheimer-Volkoff equation.
Since the equations of state of the multiquarks can be well approximated by
different power laws for small and large density, the content of the multiquark
stars has the core and crust structure. We found that most of the mass of the
star comes from the crust region where the density is relatively small. The
mass limit of the multiquark star is determined as well as its relation to the
star radius. For typical energy density scale of ,
the converging mass and radius of the hypothetical multiquark star in the limit
of large central density are approximately solar mass and 15-27 km.
The adiabatic index and sound speed distributions of the multiquark matter in
the star are also calculated and discussed. The sound speed never exceeds the
speed of light and the multiquark matters are thus compressible even at high
density and pressure.Comment: 27 pages, 17 figures, 1 table, JHEP versio
Origin of symbol-using systems: speech, but not sign, without the semantic urge
Natural language—spoken and signed—is a multichannel phenomenon, involving facial and body expression, and voice and visual intonation that is often used in the service of a social urge to communicate meaning. Given that iconicity seems easier and less abstract than making arbitrary connections between sound and meaning, iconicity and gesture have often been invoked in the origin of language alongside the urge to convey meaning. To get a fresh perspective, we critically distinguish the origin of a system capable of evolution from the subsequent evolution that system becomes capable of. Human language arose on a substrate of a system already capable of Darwinian evolution; the genetically supported uniquely human ability to learn a language reflects a key contact point between Darwinian evolution and language. Though implemented in brains generated by DNA symbols coding for protein meaning, the second higher-level symbol-using system of language now operates in a world mostly decoupled from Darwinian evolutionary constraints. Examination of Darwinian evolution of vocal learning in other animals suggests that the initial fixation of a key prerequisite to language into the human genome may actually have required initially side-stepping not only iconicity, but the urge to mean itself. If sign languages came later, they would not have faced this constraint
Rectangular Wilson Loops at Large N
This work is about pure Yang-Mills theory in four Euclidean dimensions with
gauge group SU(N). We study rectangular smeared Wilson loops on the lattice at
large N and relatively close to the large-N transition point in their
eigenvalue density. We show that the string tension can be extracted from these
loops but their dependence on shape differs from the asymptotic prediction of
effective string theory.Comment: 47 pages, 21 figures, 8 table
Holographic Approach to Regge Trajectory and Rotating D5 brane
We study the Regge trajectories of holographic mesons and baryons by
considering rotating strings and D5 brane, which is introduced as the baryon
vertex. Our model is based on the type IIB superstring theory with the
background of asymptotic . This background is dual to a
confining supersymmetric Yang-Mills theory (SYM) with gauge condensate,
, which determines the tension of the linear potential between the quark
and anti-quark. Then the slope of the meson trajectory () is given
by this condensate as at large spin . This
relation is compatible with the other theoretical results and experiments. For
the baryon, we show the importance of spinning baryon vertex to obtain a Regge
slope compatible with the one of and series. In both cases, mesons
and baryons, the trajectories are shifted to large mass side with the same
slope for increasing current quark mass.Comment: 28 pages, 7 figure
Recommended from our members
A mass media campaign are needed to counter misconceptions about back pain and promote higher value care.
Back pain is saddled by misconceptions that contribute to low-value care and poor outcomes. Many patients and clinicians mistakenly view the spine as fragile, believe that pain equates to damage, and over-emphasise the role and value of rest, imaging, medication, and surgery.1 Guideline-based care will not be embraced if such misconceptions are not countered. Here we provide four arguments for accessible, engaging and convincing education to the public and health professionals
Synchronous Symmetry Breaking in Neurons with Different Neurite Counts
As neurons develop, several immature processes (i.e., neurites) grow out of the cell body. Over time, each neuron breaks symmetry when only one of its neurites grows much longer than the rest, becoming an axon. This symmetry breaking is an important step in neurodevelopment, and aberrant symmetry breaking is associated with several neuropsychiatric diseases, including schizophrenia and autism. However, the effects of neurite count in neuronal symmetry breaking have never been studied. Existing models for neuronal polarization disagree: some predict that neurons with more neurites polarize up to several days later than neurons with fewer neurites, while others predict that neurons with different neurite counts polarize synchronously. We experimentally find that neurons with different neurite counts polarize synchronously. We also show that despite the significant differences among the previously proposed models, they all agree with our experimental findings when the expression levels of the proteins responsible for symmetry breaking increase with neurite count. Consistent with these results, we observe that the expression levels of two of these proteins, HRas and shootin1, significantly correlate with neurite count. This coordinated symmetry breaking we observed among neurons with different neurite counts may be important for synchronized polarization of neurons in developing organisms
Exact Results and Holography of Wilson Loops in N=2 Superconformal (Quiver) Gauge Theories
Using localization, matrix model and saddle-point techniques, we determine
exact behavior of circular Wilson loop in N=2 superconformal (quiver) gauge
theories. Focusing at planar and large `t Hooft couling limits, we compare its
asymptotic behavior with well-known exponential growth of Wilson loop in N=4
super Yang-Mills theory. For theory with gauge group SU(N) coupled to 2N
fundamental hypermultiplets, we find that Wilson loop exhibits non-exponential
growth -- at most, it can grow a power of `t Hooft coupling. For theory with
gauge group SU(N) x SU(N) and bifundamental hypermultiplets, there are two
Wilson loops associated with two gauge groups. We find Wilson loop in untwisted
sector grows exponentially large as in N=4 super Yang-Mills theory. We then
find Wilson loop in twisted sector exhibits non-analytic behavior with respect
to difference of two `t Hooft coupling constants. By letting one gauge coupling
constant hierarchically larger/smaller than the other, we show that Wilson
loops in the second type theory interpolate to Wilson loop in the first type
theory. We infer implications of these findings from holographic dual
description in terms of minimal surface of dual string worldsheet. We suggest
intuitive interpretation that in both type theories holographic dual background
must involve string scale geometry even at planar and large `t Hooft coupling
limit and that new results found in the gauge theory side are attributable to
worldsheet instantons and infinite resummation therein. Our interpretation also
indicate that holographic dual of these gauge theories is provided by certain
non-critical string theories.Comment: 52 pages, 7 figures v2. more figures embedded v3. minor stylistic
changes, v4. published versio
Revisiting the S-matrix approach to the open superstring low energy effective lagrangian
The conventional S-matrix approach to the (tree level) open string low energy
effective lagrangian assumes that, in order to obtain all its bosonic
order terms, it is necessary to know the open string (tree level)
-point amplitude of massless bosons, at least expanded at that order in
. In this work we clarify that the previous claim is indeed valid for
the bosonic open string, but for the supersymmetric one the situation is much
more better than that: there are constraints in the kinematical bosonic terms
of the amplitude (probably due to Spacetime Supersymmetry) such that a much
lower open superstring -point amplitude is needed to find all the
order terms. In this `revisited' S-matrix approach we have
checked that, at least up to order, using these kinematical
constraints and only the known open superstring 4-point amplitude, it is
possible to determine all the bosonic terms of the low energy effective
lagrangian. The sort of results that we obtain seem to agree completely with
the ones achieved by the method of BPS configurations, proposed about ten years
ago. By means of the KLT relations, our results can be mapped to the NS-NS
sector of the low energy effective lagrangian of the type II string theories
implying that there one can also find kinematical constraints in the -point
amplitudes and that important informations can be inferred, at least up to
order, by only using the (tree level) 4-point amplitude.Comment: 34 pages, 3 figure, Submitted on Aug 4, 2012, Published on Oct 15,
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