2,388 research outputs found
Dark Energy and Its Interactions with Neutrinos
In this talk I will firstly review on the current constraints on the equation
of state of the dark energy from observational data, then present a new
scenario of dark energy dubbed {\it Quintom}. The recent fits to the type Ia
supernova data and the cosmic microwave background and so on in the literature
find that the behavior of dark energy is to great extent in consistency with a
cosmological constant, however the dynamical dark energy scenarios are
generally not ruled out, and one class of models with an equation of state
transiting from below -1 to above -1 as the redshift increases is mildly
favored. The second part of the talk is on interacting dark energy. I will
review briefly on the models of neutrino dark energy.Comment: 7 pages, 6 figures, plenary talk given at PASCOS 2005, May 30 - June
4, Gyeongju, Kore
Dark Matter and Cosmic Strings in Particle Models
In this talk, I will discuss the mechanism of nonthermal production of the
neutralino cold dark matter from the decay of cosmic strings and the embedded
defects, the and strings in the strong interaction sector
of the standard model.Comment: 9 pages, no figure, Invited Plenary Talk Given at COSMO'99, ICTP,
Trieste, Sept.27-Oct.2, 199
Cosmological CPT violating effect on CMB polarization
A dark energy scalar (or a function of the Ricci scalar) coupled with the
derivative to the matter fields will violate the symmetry during the
expansion of the Universe. This type of cosmological violation helps to
generate the baryon number asymmetry and gives rise to the rotation of the
photon polarization which can be measured in the astrophysical and cosmological
observations, especially the experiments of the cosmic microwave background
radiation. In this paper, we derive the rotation angle in a fully general
relativistic way and present the rotation formulas used for the cosmic
microwave background data analysis. Our formulas include the corrections from
the spatial fluctuations of the scalar field. We also estimate the magnitude of
these corrections in a class of dynamical dark energy models for quintessential
baryo/leptogenesis.Comment: 12 page
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Using EPECs to model bilevel games in restructured electricity markets with locational prices
CWPE0619 (EPRG0602) Xinmin Hu and Daniel Ralph (Feb 2006) Using EPECs to model bilevel games in restructured electricity markets with locational prices We study a bilevel noncooperative game-theoretic model of electricity markets with locational marginal prices. Each player faces a bilevel optimization problem that we remodel as a mathematical program with equilibrium constraints, MPEC. This gives an EPEC, equilibrium problem with equilibrium constraints. We establish sufficient conditions for existence of pure strategy Nash equilibria for this class of bilevel games and give some applications. We show by examples the effect of network transmission limits, i.e. congestion, on existence of equilibria. Then we study, for more general EPECs, the weaker pure strategy concepts of local Nash and Nash stationary equilibria. We model the latter via complementarity problems, CPs. Finally, we present numerical examples of methods that attempt to find local Nash or Nash stationary equilibria of randomly generated electricity market games. The CP solver PATH is found to be rather effective in this context
Probing the gauge symmetry breaking of the early universe in 3-3-1 models and beyond by gravitational waves
Taking the 3-3-1 models (with gauge
group) as examples, we study that a class of new physics models with extended
gauge group could undergo one or several first-order phase transitions
associated with the spontaneously symmetry breaking processes during the
evolution of the universe, which can produce detectable phase transition
gravitational wave (GW) signals at future GW experiments, such as LISA, BBO,
DECIGO, SKA and aLIGO. These GW signals can provide new sources of GWs with
different peak frequencies, and can be used to probe the evolution history of
the universe.Comment: Published version for Physics Letters
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