1,131,084 research outputs found
The Dark Energy Survey
We describe the Dark Energy Survey (DES), a proposed optical-near infrared
survey of 5000 sq. deg of the South Galactic Cap to ~24th magnitude in SDSS
griz, that would use a new 3 sq. deg CCD camera to be mounted on the Blanco 4-m
telescope at Cerro Telolo Inter-American Observatory (CTIO). The survey data
will allow us to measure the dark energy and dark matter densities and the dark
energy equation of state through four independent methods: galaxy clusters,
weak gravitational lensing tomography, galaxy angular clustering, and supernova
distances. These methods are doubly complementary: they constrain different
combinations of cosmological model parameters and are subject to different
systematic errors. By deriving the four sets of measurements from the same data
set with a common analysis framework, we will obtain important cross checks of
the systematic errors and thereby make a substantial and robust advance in the
precision of dark energy measurements.Comment: White Paper submitted to the Dark Energy Task Force, 42 page
Dark energy without dark energy
It is proposed that the current acceleration of the universe is not
originated by the existence of a mysterious dark energy fluid nor by the action
of extra terms in the gravity Lagrangian, but just from the sub-quantum
potential associated with the CMB particles. The resulting cosmic scenario
corresponds to a benigner phantom model which is free from the main problems of
the current phantom approaches.Comment: 4 pages, 1 figure, to appear in AIP proceedings of "Dark side of the
Universe
The Dark Energy Survey
We describe the Dark Energy Survey (DES), a proposed optical-near infrared survey of 5000 sq. deg of the South Galactic Cap to ~24th magnitude in SDSS griz, that would use a new 3 sq. deg CCD camera to be mounted on the Blanco 4-m telescope at Cerro Telolo Inter-American Observatory (CTIO). The survey data will allow us to measure the dark energy and dark matter densities and the dark energy equation of state through four independent methods: galaxy clusters, weak gravitational lensing tomography, galaxy angular clustering, and supernova distances. These methods are doubly complementary: they constrain different combinations of cosmological model parameters and are subject to different systematic errors. By deriving the four sets of measurements from the same data set with a common analysis framework, we will obtain important cross checks of the systematic errors and thereby make a substantial and robust advance in the precision of dark energy measurements
Quantum Informational Dark Energy: Dark energy from forgetting
We suggest that dark energy has a quantum informational origin. Landauer's
principle associated with the erasure of quantum information at a cosmic
horizon implies the non-zero vacuum energy having effective negative pressure.
Assuming the holographic principle, the minimum free energy condition, and the
Gibbons-Hawking temperature for the cosmic event horizon we obtain the
holographic dark energy with the parameter , which is consistent
with the current observational data. It is also shown that both the
entanglement energy and the horizon energy can be related to Landauer's
principle.Comment: revtex,8 pages, 2 figures more detailed arguments adde
Dark Energy and Dark Matter
It is a puzzle why the densities of dark matter and dark energy are nearly
equal today when they scale so differently during the expansion of the
universe. This conundrum may be solved if there is a coupling between the two
dark sectors. In this paper we assume that dark matter is made of cold relics
with masses depending exponentially on the scalar field associated to dark
energy. Since the dynamics of the system is dominated by an attractor solution,
the dark matter particle mass is forced to change with time as to ensure that
the ratio between the energy densities of dark matter and dark energy become a
constant at late times and one readily realizes that the present-day dark
matter abundance is not very sensitive to its value when dark matter particles
decouple from the thermal bath. We show that the dependence of the present
abundance of cold dark matter on the parameters of the model differs
drastically from the familiar results where no connection between dark energy
and dark matter is present. In particular, we analyze the case in which the
cold dark matter particle is the lightest supersymmetric particle.Comment: 4 pages latex, 2 figure
Dark Matter and Dark Energy due to Photons that Attract or Repel Each Other
The Through a simple model we study the possibility of photon with mass and charge that can produce an attractive or repulsive force at galactic distances. The main source of the dark energy can be provided by the non-vanishing photon mass during the period of dark radiation of the Universe. A simple analysis shows that the non-vanishing photon mass of the order of is consistent with the current observations. For distances separating nearby galaxies dominates the force of Newtonian attraction between photonic masses (Dark Matter). For distant galaxies dominates the repulsive electrical force between photon charges (Dark Energy)
Dark Energy and Dark Matter
A brief overview of our current understanding of abundance and properties of
dark energy and dark matter is presented. A more focused discussion of
supersymmetric dark matter follows. Included is a frequentist approach to the
supersymmetric parameter space and consequences for the direct detection of
dark matter.Comment: 12 pages, 8 figures, Summary of talk given at the XXIV International
Symposium on Lepton Photon Interactions at High Energies, Hamburg Germany,
August 200
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