CMB Temperature Anisotropy Quadrupole Generated by Tensor Perturbation

Using the method suggested in Ref.[1] and the Cosmic Microwave Background Radiation (CMB) temperature anisotropy quadrupole observed by COBE, we find that C 2 /C S 2 = 5.9± 2.7, where C 2 and C S 2 are the CMB anisotropy quadrupole generated by tensor perturbation and scalar perturbation respectively. But if using the C 2 predicted by the standard inflationΛCDM models, we can find that C 2 /C S 2 = 0.11± 0.04. This result consists with prediction of inflation models, it also consists with the upper limit of the tensor perturbation which got from Ref.[2]. From this result, we find the contribution on the CMB anisotropy is not too small to be omitted. So it is necessary to reestimate the cosmological parameters after considering the effect of the tensor perturbation. This result also suggests that the much damping of the CMB anisotropy quadrupole may be only occurring on the contribution of scalar perturbation, but not on the tensor perturbation, this is a new character of this damping, and will be a very constraint on the explanation of it. PACS numbers: 98.80.-k 98.80.Es 04.30.-w 04.62.+v, e-mail: [email protected] The normal inflation models predict the tensor perturbation besides the scalar perturbation[3]. The detection of this kind of perturbation is very important for fixing the energy scale of the inflation, and studying the evolution of the inflation and following stages. Especially, recently a lot of people had advised some new inflation mechanizm[4], some of which suggested the inflation may occurred at very low energy scale, such as TeV . This low scale predicts that the tensor perturbation generated from inflation stage is too small to be detected. We also have study the effect of the reheating and dark energy on the tensor power spectrum, and found that the different models can give different spectrum[5]. So the research on the tensor perturbation is a kind of new way to studying the evolution process of the Universe, especially the inflation physics. There are three main ways to detect this tensor perturbation at different frequency: the direct detecting with LIGO and LISA, their sensitive frequency is 10 ∼ 10Hz[6]; the way by analyzing the timing