1,233 research outputs found
MSSM and Large from SUSY Trinification
We construct a supersymmetric model based on the semi-simple gauge group
with the relation automatically arising from its structure. The model below a scale
GeV gives naturally rise just to the minimal supersymmetric
standard model and therefore to the presently favored values for and without fields in representations higher than the
fundamental.Comment: 9 pages, LaTeX, UT-STPD-3-9
Localization of actin in Dictyostelium amebas by immunofluorescence
Antibody prepared against avian smooth muscle actin has been used to localize actin in the slime mold, Dictyostelium discoideum. The distribution of actin in migrating cells is different from that in feeding cells. Migrating amebas display fluorescence primarily in advancing regions whereas feeding amebas show uniform fluorescence throughout. The reaction is specific for actin since the fluorescence observed is blocked when the antibody is absorbed by actin purified from avian skeletal muscle, human platelets, and Dictyostelium. These results, in addition to describing the distribution of actin in D. discoideum, demonstrate that actins from these diverse sources share at least one common antigenic determinant
On the phase structure of driven quantum systems
Clean and interacting periodically driven quantum systems are believed to
exhibit a single, trivial "infinite-temperature" Floquet-ergodic phase. In
contrast, here we show that their disordered Floquet many-body localized
counterparts can exhibit distinct ordered phases delineated by sharp
transitions. Some of these are analogs of equilibrium states with broken
symmetries and topological order, while others - genuinely new to the Floquet
problem - are characterized by order and non-trivial periodic dynamics. We
illustrate these ideas in driven spin chains with Ising symmetry.Comment: v3 - published version. Discussions expanded/clarified in few place
Quark-Lepton Quartification
We propose that quarks and leptons are interchangeable entities in the
high-energy limit. This naturally results in the extension of [SU(3)]^3
trinification to [SU(3)]^4 quartification. In addition to the unbroken color
SU(3)_q of quarks, there is now also a color SU(3)_l of leptons which reduces
to an unbroken SU(2)_l. We discuss the natural occurrence of SU(2)_l doublets
at the TeV energy scale, which leads remarkably to the unification of all gauge
couplings without supersymmetry. Proton decay occurs through the exchange of
scalar bosons, with a lifetime in the range 10^{34} - 10^{36} years.Comment: 12 pages, 4 figures. Reference adde
Nonlinear Localization in Metamaterials
Metamaterials, i.e., artificially structured ("synthetic") media comprising
weakly coupled discrete elements, exhibit extraordinary properties and they
hold a great promise for novel applications including super-resolution imaging,
cloaking, hyperlensing, and optical transformation. Nonlinearity adds a new
degree of freedom for metamaterial design that allows for tuneability and
multistability, properties that may offer altogether new functionalities and
electromagnetic characteristics. The combination of discreteness and
nonlinearity may lead to intrinsic localization of the type of discrete
breather in metallic, SQUID-based, and symmetric metamaterials. We
review recent results demonstrating the generic appearance of breather
excitations in these systems resulting from power-balance between intrinsic
losses and input power, either by proper initialization or by purely dynamical
procedures. Breather properties peculiar to each particular system are
identified and discussed. Recent progress in the fabrication of low-loss,
active and superconducting metamaterials, makes the experimental observation of
breathers in principle possible with the proposed dynamical procedures.Comment: 19 pages, 14 figures, Invited (Review) Chapte
Multistability and localization in coupled nonlinear split-ring resonators
We study the dynamics of a pair of nonlinear split-ring resonators (a
`metadimer') excited by an alternating magnetic field and coupled magnetically.
Linear metadimers of this kind have been recently used as the elementary
components for three-dimensional metamaterials or 'stereometamaterials' [N. Liu
{\em et al}, Nature Photon. {\bf 3}, 157 (2009)]. We demonstrate that
nonlinearity offers more possibilities with respect to real-time tunability and
a multiplicity of states which can be reached by varying the external field.
Moreover, we demonstrate almost total localization of the energy in one of the
resonators in a broad range of parameters.Comment: 3 pages, 5 figure
Non-thermal leptogenesis via direct inflaton decay without SU(2)(L) triplets
We present a non-thermal leptogenesis scenario following standard
supersymmetric hybrid inflation, in the case where light neutrinos acquire mass
via the usual seesaw mechanism and inflaton decay to heavy right-handed
neutrino superfields is kinematically disallowed, or the right-handed neutrinos
which can be decay products of the inflaton are unable to generate sufficient
baryon asymmetry via their subsequent decay. The primordial lepton asymmetry is
generated through the decay of the inflaton into light particles by the
interference of one-loop diagrams with exchange of different right-handed
neutrinos. The mechanism requires superpotential couplings explicitly violating
a U(1) R-symmetry and R-parity. We take into account the constraints from
neutrino masses and mixing and the preservation of the primordial asymmetry. We
consider two models, one without and one with SU(2)(R) gauge symmetry. We show
that the former is viable, whereas the latter is ruled out. Although the broken
R-parity need not have currently observable low-energy signatures, some
R-parity-violating slepton decays may be detectable in the future colliders.Comment: 22 pages including 9 figures, uses Revtex, version to appear in PR
Nonlinear magnetoinductive transmission lines
Power transmission in one-dimensional nonlinear magnetic metamaterials driven
at one end is investigated numerically and analytically in a wide frequency
range. The nonlinear magnetic metamaterials are composed of varactor-loaded
split-ring resonators which are coupled magnetically through their mutual
inductances, forming thus a magnetoiductive transmission line. In the linear
limit, significant power transmission along the array only appears for
frequencies inside the linear magnetoinductive wave band. We present
analytical, closed form solutions for the magnetoinductive waves transmitting
the power in this regime, and their discrete frequency dispersion. When
nonlinearity is important, more frequency bands with significant power
transmission along the array may appear. In the equivalent circuit picture, the
nonlinear magnetoiductive transmission line driven at one end by a relatively
weak electromotive force, can be modeled by coupled
resistive-inductive-capacitive (RLC) circuits with voltage-dependent
capacitance. Extended numerical simulations reveal that power transmission
along the array is also possible in other than the linear frequency bands,
which are located close to the nonlinear resonances of a single nonlinear RLC
circuit. Moreover, the effectiveness of power transmission for driving
frequencies in the nonlinear bands is comparable to that in the linear band.
Power transmission in the nonlinear bands occurs through the linear modes of
the system, and it is closely related to the instability of a mode that is
localized at the driven site.Comment: 11 pages, 11 figures, submitted to International Journal of
Bifurcation and Chao
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