50,087 research outputs found
Resilience of the Spectral Standard Model
We show that the inconsistency between the spectral Standard Model and the
experimental value of the Higgs mass is resolved by the presence of a real
scalar field strongly coupled to the Higgs field. This scalar field was already
present in the spectral model and we wrongly neglected it in our previous
computations. It was shown recently by several authors, independently of the
spectral approach, that such a strongly coupled scalar field stabilizes the
Standard Model up to unification scale in spite of the low value of the Higgs
mass. In this letter we show that the noncommutative neutral singlet modifies
substantially the RG analysis, invalidates our previous prediction of Higgs
mass in the range 160--180 Gev, and restores the consistency of the
noncommutative geometric model with the low Higgs mass.Comment: 13 pages, more contours added to Higgs mass plot, one reference adde
Note About Hamiltonian Structure of Non-Linear Massive Gravity
We perform the Hamiltonian analysis of non-linear massive gravity action
studied recently in arXiv:1106.3344 [hep-th]. We show that the Hamiltonian
constraint is the second class constraint. As a result the theory possesses an
odd number of the second class constraints and hence all non physical degrees
of freedom cannot be eliminated.Comment: 15 page
Topological Defects Coupling Smectic Modulations to Intra-unit-cell Nematicity in Cuprate
We study the coexisting smectic modulations and intra-unit-cell nematicity in
the pseudogap states of underdoped Bi2Sr2CaCu2O8+{\delta}. By visualizing their
spatial components separately, we identified 2\pi topological defects
throughout the phase-fluctuating smectic states. Imaging the locations of large
numbers of these topological defects simultaneously with the fluctuations in
the intra-unit-cell nematicity revealed strong empirical evidence for a
coupling between them. From these observations, we propose a Ginzburg-Landau
functional describing this coupling and demonstrate how it can explain the
coexistence of the smectic and intra-unit-cell broken symmetries and also
correctly predict their interplay at the atomic scale. This theoretical
perspective can lead to unraveling the complexities of the phase diagram of
cuprate high-critical-temperature superconductors
In-line flocculation-filtration as pre-treatment to reverse osmosis desalination
In this paper the performance of single and dual media filters with in-line flocculation have been examined as pretreatment to seawater reverse osmosis (SWRO). A comparison of filter performance was made between single medium filter (80 cm) consisting of sand or anthracite, and dual media filter consisting of sand (40 cm at the bottom) and anthracite (40 cm on top). Short term (6 hours) experiments were conducted with in-line coagulation followed by direct filtration. Filtration velocities of 5 m/h and 10 m/h were used. The performances of these filters were assessed in terms of turbidity removal, head loss build-up, and organic compound removal in terms of molecular weight distribution (MWD). The efficiency of the filter as pretreatment was evaluated in terms of silt density index (SDI) and modified fouling index (MFI). It was found that the turbidity removal was high and all the filters produced more or less same quality water. There was a slower buildup of head loss for coarser filter medium. A post treatment of reverse osmosis after an inline-flocculation-dual media filtration showed lower normalized flux decline (J/J0) (0.35 to 0.22 during the first 20 hours operation) while, seawater without any pretreatment showed steeper flux decline (0.18 to 0.11 at first 20 hours operation) in RO. © 2009
Commensurate period Charge Density Modulations throughout the Pseudogap Regime
Theories based upon strong real space (r-space) electron electron
interactions have long predicted that unidirectional charge density modulations
(CDM) with four unit cell (4) periodicity should occur in the hole doped
cuprate Mott insulator (MI). Experimentally, however, increasing the hole
density p is reported to cause the conventionally defined wavevector of
the CDM to evolve continuously as if driven primarily by momentum space
(k-space) effects. Here we introduce phase resolved electronic structure
visualization for determination of the cuprate CDM wavevector. Remarkably, this
new technique reveals a virtually doping independent locking of the local CDM
wavevector at throughout the underdoped phase diagram of the
canonical cuprate . These observations have significant
fundamental consequences because they are orthogonal to a k-space (Fermi
surface) based picture of the cuprate CDM but are consistent with strong
coupling r-space based theories. Our findings imply that it is the latter that
provide the intrinsic organizational principle for the cuprate CDM state
Energy Content of Colliding Plane Waves using Approximate Noether Symmetries
This paper is devoted to study the energy content of colliding plane waves
using approximate Noether symmetries. For this purpose, we use approximate Lie
symmetry method of Lagrangian for differential equations. We formulate the
first-order perturbed Lagrangian for colliding plane electromagnetic and
gravitational waves. It is shown that in both cases, there does not existComment: 18 pages, accepted for publication in Brazilian J Physic
Fluctuations, Saturation, and Diffractive Excitation in High Energy Collisions
Diffractive excitation is usually described by the Good--Walker formalism for
low masses, and by the triple-Regge formalism for high masses. In the
Good--Walker formalism the cross section is determined by the fluctuations in
the interaction. In this paper we show that by taking the fluctuations in the
BFKL ladder into account, it is possible to describe both low and high mass
excitation by the Good--Walker mechanism. In high energy collisions the
fluctuations are strongly suppressed by saturation, which implies that pomeron
exchange does not factorise between DIS and collisions. The Dipole Cascade
Model reproduces the expected triple-Regge form for the bare pomeron, and the
triple-pomeron coupling is estimated.Comment: 20 pages, 12 figure
Machine Learning in Electronic Quantum Matter Imaging Experiments
Essentials of the scientific discovery process have remained largely
unchanged for centuries: systematic human observation of natural phenomena is
used to form hypotheses that, when validated through experimentation, are
generalized into established scientific theory. Today, however, we face major
challenges because automated instrumentation and large-scale data acquisition
are generating data sets of such volume and complexity as to defy human
analysis. Radically different scientific approaches are needed, with machine
learning (ML) showing great promise, not least for materials science research.
Hence, given recent advances in ML analysis of synthetic data representing
electronic quantum matter (EQM), the next challenge is for ML to engage
equivalently with experimental data. For example, atomic-scale visualization of
EQM yields arrays of complex electronic structure images, that frequently elude
effective analyses. Here we report development and training of an array of
artificial neural networks (ANN) designed to recognize different types of
hypothesized order hidden in EQM image-arrays. These ANNs are used to analyze
an experimentally-derived EQM image archive from carrier-doped cuprate Mott
insulators. Throughout these noisy and complex data, the ANNs discover the
existence of a lattice-commensurate, four-unit-cell periodic,
translational-symmetry-breaking EQM state. Further, the ANNs find these
phenomena to be unidirectional, revealing a coincident nematic EQM state.
Strong-coupling theories of electronic liquid crystals are congruent with all
these observations.Comment: 44 pages, 15 figure
The Self-Accelerating Universe with Vectors in Massive Gravity
We explore the possibility of realising self-accelerated expansion of the
Universe taking into account the vector components of a massive graviton. The
effective action in the decoupling limit contains an infinite number of terms,
once the vector degrees of freedom are included. These can be re-summed in
physically interesting situations, which result in non-polynomial couplings
between the scalar and vector modes. We show there are self-accelerating
background solutions for this effective action, with the possibility of having
a non-trivial profile for the vector fields. We then study fluctuations around
these solutions and show that there is always a ghost, if a background vector
field is present. When the background vector field is switched off, the ghost
can be avoided, at the price of entering into a strong coupling regime, in
which the vector fluctuations have vanishing kinetic terms. Finally we show
that the inclusion of a bare cosmological constant does not change the previous
conclusions and it does not lead to a ghost mode in the absence of a background
vector field.Comment: 23 pages, 2 figure
Endo-lysosomal TRP mucolipin-1 channels trigger global ER Ca2+ release and Ca2+ influx.
Transient receptor potential (TRP) mucolipins (TRPMLs), encoded by the MCOLN genes, are patho-physiologically relevant endo-lysosomal ion channels crucial for membrane trafficking. Several lines of evidence suggest that TRPMLs mediate localised Ca(2+) release but their role in Ca(2+) signalling is not clear. Here, we show that activation of endogenous and recombinant TRPMLs with synthetic agonists evoked global Ca(2+) signals in human cells. These signals were blocked by a dominant-negative TRPML1 construct and a TRPML antagonist. We further show that, despite a predominant lysosomal localisation, TRPML1 supports both Ca(2+) release and Ca(2+) entry. Ca(2+) release required lysosomal and ER Ca(2+) stores suggesting that TRPMLs, like other endo-lysosomal Ca(2+) channels, are capable of 'chatter' with ER Ca(2+) channels. Our data identify new modalities for TRPML1 action
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