2,473 research outputs found
Holographic RG Flow in a New Sector of -Deformed Gauged Supergravity
We consider a certain supersymmetric,
invariant, subsector of the -deformed family of -gauged four-dimensional supergravities. The theory contains two scalar fields
and two pseudoscalar fields. We look for stationary points of the scalar
potential, corresponding to AdS vacua in the theory. One of these, which breaks
all supersymmetries but is nonetheless stable, is new. It exists only when
. We construct supersymmetric domain wall solutions in the
truncated theory, and we give a detailed analysis of their holographic dual
interpretations using the AdS/CFT correspondence. Domain walls where the
pseudoscalars vanish were studied previously, but those with non-vanishing
pseudoscalars, which we analyse numerically, are new. The pseudoscalars are
associated with supersymmetric mass deformations in the CFT duals. When
is zero, the solutions can be lifted to M-theory, where they approach
the Coulomb-branch flows of dielectric M5-branes wrapped on in the deep
IR.Comment: 40 pages, 10 figure
Topological Aspect of Knotted Vortex Filaments in Excitable Media
Scroll waves exist ubiquitously in three-dimensional excitable media. It's
rotation center can be regarded as a topological object called vortex filament.
In three-dimensional space, the vortex filaments usually form closed loops, and
even linked and knotted. In this letter, we give a rigorous topological
description of knotted vortex filaments. By using the -mapping
topological current theory, we rewrite the topological current form of the
charge density of vortex filaments and use this topological current we reveal
that the Hopf invariant of vortex filaments is just the sum of the linking and
self-linking numbers of the knotted vortex filaments. We think that the precise
expression of the Hopf invariant may imply a new topological constraint on
knotted vortex filaments.Comment: 4 pages, no figures, Accepted by Chin. Phys. Let
Multi-Player and Multi-Choice Quantum Game
We investigate a multi-player and multi-choice quantum game. We start from
two-player and two-choice game and the result is better than its classical
version. Then we extend it to N-player and N-choice cases. In the quantum
domain, we provide a strategy with which players can always avoid the worst
outcome. Also, by changing the value of the parameter of the initial state, the
probabilities for players to obtain the best payoff will be much higher that in
its classical version.Comment: 4 pages, 1 figur
Discovery of Lorentz-violating Weyl fermion semimetal state in LaAlGe materials
We report theoretical and experimental discovery of Lorentz-violating Weyl
fermion semimetal type-II state in the LaAlGe class of materials. Previously
type-II Weyl state was predicted in WTe2 materials which remains unrealized in
surface experiments. We show theoretically and experimentally that LaAlGe class
of materials are the robust platforms for the study of type-II Weyl physics.Comment: This paper reports theoretical prediction and experimental discovery
together. A detailed theoretical paper describing the topology of the full
family of X(Lanthanides)AlGe materials will follow. Other related papers can
be found at http://physics.princeton.edu/zahidhasangroup/index_WS.htm
The jet power, radio loudness and black hole mass in radio loud AGNs
The jet formation is thought to be closely connected with the mass of central
supermassive black hole in Active Galactic Nuclei. The radio luminosity
commonly used in investigating this issue is merely an indirect measure of the
energy transported through the jets from the central engine, and severely
Doppler boosted in core-dominated radio quasars. In this work, we investigate
the relationship between the jet power and black hole mass, by estimating the
jet power using extrapolated extended 151 MHz flux density from the VLA 5 GHz
extended radio emission, for a sample of 146 radio loud quasars complied from
literature. After removing the effect of relativistic beaming in the radio and
optical emission, we find a significant intrinsic correlation between the jet
power and black hole mass. It strongly implies that the jet power, so as jet
formation, is closely connected with the black hole mass.To eliminate the
beaming effect in the conventional radio loudness, we define a new radio
loudness as the ratio of the radio extended luminosity to the optical
luminosity estimated from the broad line luminosity.In a tentatively combined
sample of radio quiet with our radio loud quasars, the apparent gap around the
conventional radio loudness R=10 is not prominent for the new-defined radio
loudness. In this combined sample, we find a significant correlation between
the black hole mass and new-defined radio loudness.Comment: 35 pages, 10 figures. accepted by Ap
GRB 120422A: A Low-luminosity Gamma-ray Burst Driven by Central Engine
GRB 120422A is a low-luminosity Gamma-ray burst (GRB) associated with a
bright supernova, which distinguishes itself by its relatively short T90 ~ 5 s
and an energetic X-ray tail. We analyze the Swift BAT and XRT data and discuss
the physical implications. We show that the early steep decline in the X-ray
light curve can be interpreted as the curvature tail of a late emission episode
around 58-86 s, with a curved instantaneous spectrum at the end of the emission
episode. Together with the main activity in the first ~ 20 s and the weak
emission from 40 s to 60 s, the prompt emission is variable, which points
towards a central engine origin, in contrast to the shock breakout origin as
invoked to interpret some other nearby low-luminosity supernova GRBs. The
curvature effect interpretation and interpreting the early shallow decay as the
coasting external forward shock emission in a wind medium both give a
constraint on the bulk Lorentz factor \Gamma to be around several. Comparing
the properties of GRB 120422A and other supernova GRBs, we found that the main
criterion to distinguish engine-driven GRBs from the shock breakout GRBs is the
time-averaged luminosity, with a separation line of about ~ 10^48 erg s^-1.Comment: ApJ accepted version; 6 pages, 1 table, 5 figures; minor changes;
references update
Broad-line region in NGC 4151 monitored by two decades of reverberation mapping campaigns. I. Evolution of structure and kinematics
We report the results of long-term reverberation mapping (RM) campaigns of
the nearby active galactic nuclei (AGN) NGC 4151, spanning from 1994 to 2022,
based on archived observations of the FAST Spectrograph Publicly Archived
Programs and our new observations with the 2.3m telescope at the Wyoming
Infrared Observatory. We reduce and calibrate all the spectra in a consistent
way, and derive light curves of the broad H line and 5100\,{\AA}
continuum. Continuum light curves are also constructed using public archival
photometric data to increase sampling cadences. We subtract the host galaxy
contamination using {\it HST} imaging to correct fluxes of the calibrated light
curves. Utilizing the long-term archival photometric data, we complete the
absolute flux-calibration of the AGN continuum. We find that the H time
delays are correlated with the 5100\,{\AA} luminosities as . This is remarkably consistent with
Bentz et al. (2013)'s global size-luminosity relationship of AGNs. Moreover,
the data sets for five of the seasons allow us to obtain the velocity-resolved
delays of the H line, showing diverse structures (outflows, inflows and
disks). Combining our results with previous independent measurements, we find
the measured dynamics of the H broad-line region (BLR) are possibly
related to the long-term trend of the luminosity. There is also a possible
additional 1.86 years time lag between the variation in BLR radius and
luminosity. These results suggest that dynamical changes in the BLR may be
driven by the effects of radiation pressure.Comment: Accepted for publication in MNRAS; comments welcome
IL-6-174 G/C and -572 C/G Polymorphisms and Risk of Alzheimer’s Disease
Associations between interleukin 6 (IL-6) polymorphisms and Alzheimer’s disease (AD) remain controversial and ambiguous. The aim of this meta-analysis is to explore more precise estimations for the relationship between IL-6-174 G/C and -572 C/G polymorphisms and risk for AD. Electronic searches for all publications in databases PubMed and EMBASE were conducted on the associations between IL-6 polymorphisms and risk for AD until January 2012. Odds ratio (OR) and 95% confidence intervals (CIs) were calculated using fixed and random effects models. Twenty-seven studies were included with a total of 19,135 individuals, involving 6,632 AD patients and 12,503 controls. For IL-6-174 G/C polymorphism, the combined results showed significant differences in recessive model (CC vs. CG+GG: OR = 0.65, 95%CI = 0.52–0.82). As regards IL-6-572 C/G polymorphism, significant associations were shown in dominant model (CG+GG vs. CC: OR = 0.73, 95% CI = 0.62–0.86) and in additive model (GG vs. CC, OR = 0.66, 95% CI = 0.46–0.96). In conclusion, genotype CC of IL-6-174 G/C and genotype GG plus GC of IL-6-572 C/G could decrease the risk of AD
Inhibition of Lipoprotein-Associated Phospholipase A2 Ameliorates Inflammation and Decreases Atherosclerotic Plaque Formation in ApoE-Deficient Mice
Lipoprotein-associated phospholipase A2 (Lp-PLA2) is thought to play modulatory roles in the development of atherosclerosis. Here we evaluated the effects of a specific lp-PLA2 inhibitor on atherosclerosis in ApoE-deficient mice and its associated mechanisms.ApoE-deficient mice fed an atherogenic high-fat diet for 17 weeks were divided into two groups. One group was administered the specific lp-PLA2 inhibitor, darapladib (50 mg/kg/day; p.o.) daily for 6 weeks, while the control group was administered saline. We observed no differences in body weight and serum lipids levels between the two groups at the end of the dietary period. Notably, serum lp-PLA2 activity as well as hs-CRP (C-reactive protein) and IL-6 (Interleukin-6) levels were significantly reduced in the darapladib group, compared with the vehicle group, while the serum PAF (platelet-activating factor) levels were similar between the two groups. Furthermore, the plaque area through the arch to the abdominal aorta was reduced in the darapladib group. Another finding of interest was that the macrophage content was decreased while collagen content was increased in atherosclerotic lesions at the aortic sinus in the darapladib group, compared with the vehicle group. Finally, quantitative RT-PCR performed to determine the expression patterns of specific inflammatory genes at atherosclerotic aortas revealed lower expression of MCP-1, VCAM-1 and TNF-α in the darapladib group. inflammation and decreased plaque formation in ApoE-deficient mice, supporting an anti-atherogenic role during the progression of atherosclerosis
- …