#### marcus

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In the last couple of years there'v been several papers on this, often by people I hadn't heard of before. The question came up in another thread "can you summarize in a single post" the various ideas being discussed? Personally I couldn't but I can dig up some links. Toss them out for you to look at. Maybe I can evaluate and organize some later. Busy this afternoon with other stuff, though.

I only want 2007-2009 stuff. Here's one that was accepted by Physical Review Letters:

http://arxiv.org/abs/0902.0928

Xin Zhang, Jingfei Zhang, Jinglei Cui, Li Zhang

6 pages, accepted for publication in Mod. Phys. Lett. A

(Submitted on 5 Feb 2009)

"In this paper we discuss the inflationary universe in the context of a Chaplygin gas equation of state within the framework of the effective theory of loop quantum cosmology. Under the slow-roll approximation, we calculate the primordial perturbations for this model. We give the general expressions of the scalar spectral index, its running, and the tensor-to-scalar ratio, etc. For the chaotic inflation with a quadratic potential, using the WMAP 5-year results, we determine the parameters of the Chaplygin inflation model in loop quantum cosmology. The results are consistent with the WMAP observations."

Here's one by Jack Mielczarek of whom I have a good impression from past work

http://arxiv.org/abs/0902.2490

Jakub Mielczarek

13 pages, 13 figures

(Submitted on 14 Feb 2009)

"In this paper we consider tensor perturbations produced at a bounce phase in presence of the holonomy corrections. Here bounce phase and holonomy corrections originate from Loop Quantum Cosmology. We re-derive formulas for the of the corrections for the model with a scalar field content. Background dynamics with a free scalar field and multi-fluid potential are considered. Both analytical approximations as well as numerical investigations were performed. We have found analytical solutions on super-horizontal and sub-horizontal regimes and derived corresponding power spectra. Also occupation number [tex]n_{\bf k}[/tex] and parameter [tex]\Omega_{\text{gw}}[/tex] were derived in sub-horizontal limit, leading to its extremely low present value. Final results are numerical power spectra of the gravitational waves produced in the presence of quantum holonomy corrections. In the super-horizontal limit the obtained spectrum behaves like [tex]\mathcal{P}_T \propto k^3(C_1+\log^2(k))[/tex] while on sub-horizontal scales it exhibits oscillations around [tex]\mathcal{P}_T \propto k^2[/tex]. These results can be directly applied as initial conditions for the inflationary modes. We mention possible resulting observational features of the CMB in particular BB spectrum of polarization."

http://arxiv.org/abs/0810.0104

E. J. Copeland, D. J. Mulryne, N. J. Nunes, M. Shaeri

8 pages, 3 figures

(Submitted on 1 Oct 2008)

"We investigate the behaviour of tensor fluctuations in Loop Quantum Cosmology, focusing on a class of scaling solutions which admit a near scale-invariant scalar field power spectrum. We obtain the spectral index of the gravitational field perturbations, and find a strong blue tilt in the power spectrum with [tex]n_t \approx 2[/tex]. The amplitude of tensor modes are, therefore, suppressed by many orders of magnitude on large scales compared to those predicted by the standard inflationary scenario where [tex]n_t \approx 0[/tex]."

Sorry, there's a bunch more but I've other things I have to do. Will try to add to this later...

I only want 2007-2009 stuff. Here's one that was accepted by Physical Review Letters:

http://arxiv.org/abs/0902.0928

**Chaplygin inflation in loop quantum cosmology**Xin Zhang, Jingfei Zhang, Jinglei Cui, Li Zhang

6 pages, accepted for publication in Mod. Phys. Lett. A

(Submitted on 5 Feb 2009)

"In this paper we discuss the inflationary universe in the context of a Chaplygin gas equation of state within the framework of the effective theory of loop quantum cosmology. Under the slow-roll approximation, we calculate the primordial perturbations for this model. We give the general expressions of the scalar spectral index, its running, and the tensor-to-scalar ratio, etc. For the chaotic inflation with a quadratic potential, using the WMAP 5-year results, we determine the parameters of the Chaplygin inflation model in loop quantum cosmology. The results are consistent with the WMAP observations."

Here's one by Jack Mielczarek of whom I have a good impression from past work

http://arxiv.org/abs/0902.2490

**Tensor power spectrum with holonomy corrections in LQC**Jakub Mielczarek

13 pages, 13 figures

(Submitted on 14 Feb 2009)

"In this paper we consider tensor perturbations produced at a bounce phase in presence of the holonomy corrections. Here bounce phase and holonomy corrections originate from Loop Quantum Cosmology. We re-derive formulas for the of the corrections for the model with a scalar field content. Background dynamics with a free scalar field and multi-fluid potential are considered. Both analytical approximations as well as numerical investigations were performed. We have found analytical solutions on super-horizontal and sub-horizontal regimes and derived corresponding power spectra. Also occupation number [tex]n_{\bf k}[/tex] and parameter [tex]\Omega_{\text{gw}}[/tex] were derived in sub-horizontal limit, leading to its extremely low present value. Final results are numerical power spectra of the gravitational waves produced in the presence of quantum holonomy corrections. In the super-horizontal limit the obtained spectrum behaves like [tex]\mathcal{P}_T \propto k^3(C_1+\log^2(k))[/tex] while on sub-horizontal scales it exhibits oscillations around [tex]\mathcal{P}_T \propto k^2[/tex]. These results can be directly applied as initial conditions for the inflationary modes. We mention possible resulting observational features of the CMB in particular BB spectrum of polarization."

http://arxiv.org/abs/0810.0104

**The gravitational wave background from super-inflation in Loop Quantum Cosmology**E. J. Copeland, D. J. Mulryne, N. J. Nunes, M. Shaeri

8 pages, 3 figures

(Submitted on 1 Oct 2008)

"We investigate the behaviour of tensor fluctuations in Loop Quantum Cosmology, focusing on a class of scaling solutions which admit a near scale-invariant scalar field power spectrum. We obtain the spectral index of the gravitational field perturbations, and find a strong blue tilt in the power spectrum with [tex]n_t \approx 2[/tex]. The amplitude of tensor modes are, therefore, suppressed by many orders of magnitude on large scales compared to those predicted by the standard inflationary scenario where [tex]n_t \approx 0[/tex]."

Sorry, there's a bunch more but I've other things I have to do. Will try to add to this later...

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