3,834 research outputs found
Emergence of gravity from interacting simplices
We consider a statistical model of interacting 4-simplices fluctuating in an
N-dimensional target space. We argue that a gravitational theory may arise as a
low energy effective theory in a strongly interacting phase where the simplices
form clusters with an emergent space and time with the Euclidean signature. In
the large N limit, two possible phases are discussed, that is, `gravitational
Coulomb phase' and `gravitational Higgs phase'.Comment: 18 pages, 6 figures, one-column format; major revisions in version 5
: reviews on emergent gauge theories added; microscopic simplex model for
emergent gravity added; erroneous statements on diffeomorphism invariance
remove
Stability of the U(1) spin liquid with spinon Fermi surface in 2+1 dimensions
We study the stability of the 2+1 dimensional U(1) spin liquid state against
proliferation of instantons in the presence of spinon Fermi surface. By mapping
the spinon Fermi surface into an infinite set of 1+1 dimensional chiral
fermions, it is argued that an instanton has an infinite scaling dimension for
any nonzero number of spinon flavors. Therefore, the spin liquid phase is
stable against instantons and the non-compact U(1) gauge theory is a good low
energy description.Comment: 14 pages, 7 figures, v3) minor corrections, to appear in PR
Scrutinising the exceptionalism of young rural NEETs: A bibliometric review
The situation of rural NEETs aged 15 to 24 remains understudied. However, transitions from adolescence to emerging adulthood are very demanding for those in the countryside. Our paper discusses this gap by characterising the scholarship focusing on rural NEETs. We undertook a bibliometric review based on 325 entries on Web of Science (WoS) using the Bibliometrix analysis package. Our approach included descriptive bibliometric analysis, co-citation networks assessment, and thematic analysis. Our findings show that the investigation efforts depicting younger rural NEET are recent and marginal in the larger context of international NEETs scholarship. The field is dominated by economy- and sociology-led networks. Concerns regarding health and employment issues are central in international publishing trends, showing a dominant youth-at-risk approach to this group. Still, themes associated with adolescent NEETs and relevant programs’ assessment are gaining traction. Our findings show a need for funding research initiatives to reduce the invisibility of young rural NEETs.info:eu-repo/semantics/acceptedVersio
Discovery of Coupling between Periodic and Aperiodic Variability and X-ray Quasi-periodic Oscillations from Her X-1
We report the discovery of coupling between periodic and aperiodic
variability and ~12-mHz X-ray quasi-periodic oscillations (QPOs) from the X-ray
binary pulsar Her X-1 using data from the Rossi X-Ray Timing Explorer. We found
two different couplings, one during the pre-eclipse dips and the other during
the normal state of the source, using a method which directly compares the
low-frequency power-density spectra (PDS) with those of the sidebands around
the coherent pulse frequency. The pre-eclipse dip lightcurves show significant
time variation of photon counts, and this variation appears in the PDS as both
strong mHz powers and well-developed sidebands around the coherent pulse
frequency. The linear correlation coefficients between the mHz PDS and the
sideband PDS obtained from two pre-eclipse dip data segments are 0.880 +- 0.003
and 0.982 +- 0.001, respectively. This very strong coupling demonstrates that
the amplitudes of the coherent pulsations are almost exactly modulated by the
aperiodic variabilities, suggesting that both the periodic and aperiodic
variabilities are related to time variation of obscuration of X-rays from the
central pulsar by an accretion disk during pre-eclipse dips. We also found weak
coupling during the normal state of the source, together with ~12-mHz QPOs. The
normal state coupling seems to reconcile with the prediction that the aperiodic
variabilities from X-ray binary pulsars are due to time-varying accretion flows
onto the pulsar's magnetic poles. If the ~12-mHz QPOs are due to global-normal
disk oscillations caused by the gravitational interactions between the central
pulsar and the accretion disk, the inferred inner-disk radius is roughly
comparable to the magnetospheric radius, ~1 10^8 cm.Comment: 13 pages (including 5 figures), submitted to ApJL (revised after
referee's report
Higgs Mediated EDMs in the Next-to-MSSM: An Application to Electroweak Baryogenesis
We perform a study on the predictions of electric-dipole moments (EDMs) of
neutron, Mercury (Hg), Thallium (Tl), deuteron, and Radium (Ra) in the
framework of next-to-minimal supersymmetric standard model (NMSSM) with
CP-violating parameters in the superpotential and soft-supersymmetry-breaking
sector. We confine to the case in which only the physical tree-level CP phase
, associated with the couplings of the singlet
terms in the superpotential and with the vacuum-expectation-values (VEVs),
takes on a nonzero value. We found that the one-loop contributions from
neutralinos are mostly small while the two-loop Higgs-mediated contributions of
the Barr-Zee (BZ) type diagrams dominate. We emphasize a scenario motivated by
electroweak baryogenesis.Comment: 36 pages, 9 figures, to appear in PR
Electron Heat Flow Due to Magnetic Field Fluctuations
Radial heat transport induced by magnetic field line fluctuations is obtained from the integral parallel heat flow closure for arbitrary collisionality. The parallel heat flow and its radial component are computed for a single harmonic sinusoidal field line perturbation. In the collisional and collisionless limits, averaging the heat flow over an unperturbed surface yields Rechester-Rosenbluth like formulae with quantitative factors. The single harmonic result is generalized to multiple harmonics given a spectrum of small magnetic perturbations. In the collisionless limit, the heat and particle transport relations are also derived. © 2016 IOP Publishing Ltd
[Fe II] and H2 filaments in the Supernova Remnant G11.2-0.3: Supernova Ejecta and Presupernova Circumstellar Wind
We present the results of near-infrared imaging and spectroscopic
observations of the young, core-collapse supernova remnant (SNR) G11.2-0.3. In
the [Fe II] 1.644 um image, we first discover long, clumpy [Fe II] filaments
within the radio shell of the SNR, together with some faint, knotty features in
the interior of the remnant. We have detected several [Fe II] lines and HI Br-G
line toward the peak position of the bright southeastern [Fe II] filament. The
derived extinction is large (Av=13 mag) and it is the brightest [Fe II]
filament detected toward SNRs to date. By analyzing two [Fe II] 1.644 um images
obtained in 2.2 yrs apart, we detect a proper motion corresponding to an
expansion rate of 0.''035 (0.''013) /yr [or 830 (310) km/s]. We also discover
two small H2 filaments. One is bright and along the SE boundary of the radio
shell, while the other is faint and just outside of its NE boundary. We have
detected H2 (2-1) S(3) line toward the former filament and derive an excitation
temperature of 2,100 K. We suggest that the H2 filaments are dense clumps in a
presupernova circumstellar wind swept up by the SNR shock while the [Fe II]
filaments are probably composed of both shocked wind material and shocked
supernova (SN) ejecta. The distribution of [Fe II] filaments may indicate that
the SN explosion in G11.2-0.3 was asymmetric as in Cassiopeia A. Our results
support the suggestion that G11.2-0.3 is a remnant of a SN IIL/b interacting
with a dense red supergiant wind.Comment: 30 pages with 10 figures, To appear in the Astrophysical Journa
Perancangan Peta Jalan Pengembangunan Industri Hasil Pertanian Pada Wilayah Kabupaten Dengan Metode VRISA Dan Rantai Nilai
.Industry development is an alternative in social welfare improvement of a region. This research was conducted to develop a road map of industry development in Kabupaten Bengkayang, West Kalimantan. VRISA (Value, Rare, In-imitabillity, Substitutability and Appropriability) framework used to determine appropriate industrial products to be developed. Based on value chain method, the development strategy was constructed into main value chain and supporting value chain strategy. Output of analysis showed that corn-based product was preferred by VRISA framework, so it needs to be developed as appropriate industry for Kabupaten Bengkayang. There are three stages of industrial development in the corn-based industry, namely initial phase (basic foundation establishment), main phase (implementation), and final stage (harvesting). Time frame for all stages takes five years
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