相关论文: Noncommutative KKLMMT Model
A generic class of string theories predicts the existence of light moduli fields, and they are expected to have masses $m_\phi$ comparable to the gravitino mass $m_{3/2}$ which is in a range of $10^{-2}$keV--1GeV in gauge-mediated…
We review the quantization of open string in NS-NS background and demonstrate that its endpoint becomes noncommutative. The same approach allows us to determine the noncommutativity that arises for a charged open string in background gauge…
We study the phases of the 1+1 dimensional Non-Commutative Open String theory on a circle. We find that the length scale of non-commutativity increases at strong coupling, the coupling in turn being dressed by a power of D-string charge.…
We perform an extensive suite of N-body simulations of the matter power spectrum, incorporating massive neutrinos in the range M = 0.15-0.6 eV, probing the non-linear regime at scales k < 10 hMpc-1 at z < 3. We extend the widely used…
We analyze cosmic superstring models in light of NANOGrav 15-year pulsar timing data. A good fit is found for a string tension $G \mu \sim 10^{-12} - 10^{-11}$ and a string intercommutation probability $p \sim 10^{-3} - 10^{-1}$.…
General Relativity receives quantum corrections relevant at cosmological distance scales from the conformal scalar degrees of freedom required by the trace anomaly of the quantum stress tensor in curved space. In the theory including the…
We elaborate on the dynamics of noncommutative two-dimensional gauge field theories. We consider U(N) gauge theories with fermions in either the fundamental or the adjoint representation. Noncommutativity leads to a rather non-trivial…
A deformed Bianchi type I metric in noncommutative gauge gravity is obtained. The gauge potential (tetrad fields) and scalar curvature are determined up to the second order in the noncommutativity parameters. The noncommutativity correction…
Noncommutative solitons are easier to find in a noncommutative field theory. Similarly, the one-loop quantum corrections to the mass of a noncommutative soliton are easier to compute, in a real scalar theory in 2+1 dimensions. We carry out…
In this paper we present noncommutative version of scalar field cosmology. We find the noncommutative Friedmann equations as well as the noncommutative Klein-Gordon equation. Interestingly the noncommutative contributions are only present…
The existence of a fundamental length (or fundamental time) has been conjecture in many contexts. Here one discusses some consequences of a fundamental constant of this type, which emerges as a consequence of deformation-stability…
The recent WMAP data represents a milestone in cosmology and helps constrain cosmological parameters with unprecedented accuracy. In this work we combine the WMAP data with previous CMB anisotropy measurements at smaller angular scales to…
Understanding the behavior of the matter power spectrum on non-linear scales beyond the $\Lambda$CDM model is crucial for accurately predicting the large-scale structure (LSS) of the Universe in non-standard cosmologies. In this work, we…
We examine W pair production in the Noncommutative Standard Model constructed with the Seiberg-Witten map. Consideration of partial wave unitarity in the reactions WW to WW and e+e- to WW shows that the latter process is more sensitive and…
A new approach to composite superconformal strings is considered . This composite string model has two scales: first one (~1 Gev) is for edging surfaces and second one (Planck scale) is for ridge surfaces . Nonlinear realization of…
Recently, two issues concerning the three-year WMAP likelihood code were pointed out. On large angular scales ($l \lesssim 30$), a sub-optimal likelihood approximation resulted in a small power excess. On small angular scales ($l \gtrsim…
We present a fitting formula for the non-linear evolution of the bispectrum in CDM models, obtained from measurements in high resolution numerical simulations. The formula interpolates between the perturbative and highly non-linear regimes,…
Localized noncommutative structures for manifolds with connection are constructed based on the use of vertical star products. The model's main feature is that two points that are far away from each other will not be subject to a deviation…
We study linear power spectra and formation of large scale structures in flat cosmological models with $\Lambda \ge 0$ and cold plus hot dark matter components (MLM). The hot component consists of massive neutrinos with cosmological density…
We show that in a wide class of string derived models of particle physics, heavy string modes with masses around the GUT scale can serve as a viable dark matter candidate. These heavy string modes wind around specific cycles in the…