55,613 research outputs found
Holographic Geometry and Noise in Matrix Theory
Using Matrix Theory as a concrete example of a fundamental holographic
theory, we show that the emergent macroscopic spacetime displays a new
macroscopic quantum structure, holographic geometry, and a new observable
phenomenon, holographic noise, with phenomenology similar to that previously
derived on the basis of a quasi-monochromatic wave theory. Traces of matrix
operators on a light sheet with a compact dimension of size are interpreted
as transverse position operators for macroscopic bodies. An effective quantum
wave equation for spacetime is derived from the Matrix Hamiltonian. Its
solutions display eigenmodes that connect longitudinal separation and
transverse position operators on macroscopic scales. Measurements of transverse
relative positions of macroscopically separated bodies, such as signals in
Michelson interferometers, are shown to display holographic nonlocality,
indeterminacy and noise, whose properties can be predicted with no parameters
except . Similar results are derived using a detailed scattering calculation
of the matrix wavefunction. Current experimental technology will allow a
definitive and precise test or validation of this interpretation of holographic
fundamental theories. In the latter case, they will yield a direct measurement
of independent of the gravitational definition of the Planck length, and a
direct measurement of the total number of degrees of freedom.Comment: 19 pages, 2 figures; v2: factors of Planck mass written explicitly,
typos correcte
Helically symmetric N-particle solutions in scalar gravity
Within a scalar model theory of gravity, where the interaction between
particles is given by the half-retarded + half-advanced solution of the scalar
wave equation, we consider an N-body problem: we investigate configurations of
N particles which form an equilateral N-angle and are in helical motion about
their common center. We prove that there exists a unique equilibrium
configuration and compute the equilibrium radius explicitly in a post-Newtonian
expansion.Comment: 5 pages, 1 figure; minor corrections and changes; accepted for
publication in Physical Review Letter
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Analysis of the Importance of Extension in Accounting for the Post-Carboniferous Subsidence of the North Sea Basin
Post Carboniferous sedimentary deposition in the Central North Sea basins can be separated into three major periods: Permian, Triassic and mid-Jurassic through present. Most efforts to explain the basin within an extensional framework have concentrated on the post mid-Jurassic subsidence. These efforts have ignored the large amount of prior extension required to account for the observed crustal thinning and the substantial Permian and Triassic sediment fill. In addition the models predict a mid-Jurassic through early Cretaceous extension that significantly exceeds estimates of the horizontal displacement observed on high angle faults on multichannel seismic lines. We show in areas of minimal pre-Permian subsidence that adding two earlier phase extensions, one in the late Carboniferous through early Permian and the other in the Triassic produces a nearly horizontal late Carboniferous crustal thickness. The time-dependent extensional model required to account for the three periods of sediment deposition gives an excellent match to the observed subsidence history of the basement. We present an analysis of a recent seismic reflection line nm across the Central Graben in the vicinity of published refraction and well data. We show that the extension required in the third phase of the three phase model is compatible with the observed displacement on the high angle mid-Jurassic through early Cretaceous faults. However, we find no evidence for major extension either in the Triassic or late Carboniferous through early Permian.Institute for Geophysic
Post-weaning performance and carcass characteristics of steer progency from different suckler cow breed types
peer-reviewedIn two experiments a total of 44 steer progeny of spring-calving Charolais (C) and
Hereford × Friesian (HF) suckler cows and C sires were slaughtered at approximately
2 years of age. Following weaning they were offered silage and 1 kg of concentrate per
head daily during a 5 month winter after which they spent 7 months at pasture. In
Experiment 1, animals were given a silage/concentrate diet during a finishing period of
either 95 or 152 days. In Experiment 2, steers were offered either a daily diet of silage
plus 6 kg of concentrates or concentrates to appetite plus 5 kg of silage (fresh weight)
during the final 140-day finishing period. Following slaughter, an 8-rib pistola from
each animal was dissected. For the two experiments combined C and HF progeny had
carcass weights of 372 and 385 (s.e. 6.1) kg, proportions of carcass as pistola of 467 and
454 (s.e. 2.8) g/kg and pistola meat proportions of 676 and 642 (s.e. 5.1) g/kg, respectively.
All fat traits were lower for the C than HF progeny but there was no difference
in carcass conformation score. Increasing slaughter weight increased carcass weight
(P < 0.001), kidney plus channel fat weight (P < 0.001), and pistola fat proportion
(P < 0.001) and decreased the proportions of carcass as pistola (P < 0.05), pistola
meat (P < 0.01), and bone (P < 0.05). In conclusion, breed type had no effect on carcass
growth but the C progeny had higher meat yield than the HF. Increasing slaughter
weight increased fatness and reduced meat yield
Dust in regions of massive star formation
It is suggested that protostars increase mass by accreting the surrounding gas and dust. Grains are destroyed as they near the central protostar creating a dust shell or cocoon. Radiation pressure acting on the grains can halt the inflow of material thereby limiting the amount of mass accumulated by the protostar. General constraints were considered on the initial dust-to-gas ratio and mass accretion rates that permit inflow. These results were constrained further by constructing a numerical model, including radiative deceleration on grains and grain destruction processes. Also the constraints on dust properties were investigated which allow the formation of massive stars. The obtained results seem to suggest that massive star formation requires rather extreme preconditioning of the grain and gas environment
Detection of Hemlock Woolly Adelgid (Hemiptera: Adelgidae) Infestations with Sticky Traps
We deployed sticky traps underneath the crown of eastern hemlock, Tsuga canadensis (L.) Carrière, to assess their sensitivity at detecting crawlers (1st instar nymphs) of the non-native hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae). We found these traps more sensitive at detecting infested trees with low densities of A. tsugae than branch-tip sampling with pole pruners. We observed two peaks of crawler abundance at all sites: these peaks likely represented the timing of the progrediens and sistens crawler stages of A. tsugae. Deployment of sticky traps in treated and high-risk stands may prove useful at detecting residual and new infestations, respectively
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