Brane annihilations during inflation

Battefeld, Diana; Battefeld, Thorsten; Firouzjahi, Hassan; Khosravi, Nima

doi:10.1088/1475-7516/2010/07/009

Cited by 25 publications

(70 citation statements)

References 105 publications

(223 reference statements)

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“…We derived this bound in a sudden transition approximation, which cuts out the intermediate, non-trivial dynamics of the heavy field and truncates fluctuations to the light sector. This approximation is not new and the result is identical to the one derived for decaying inflatons in [65]. However, it is far from obvious that this simplistic approximation provides a good estimate: the temporary deviation of the equation of state parameter during the excitation event is considerably bigger than its asymptotic change relevant for the estimate, see Fig.…”

Section: Resultssupporting

confidence: 58%

“…Plugging the solutions in (3.39) and (4.22) into the matching conditions, we can calculate the Bogoliubov coefficients to Since the details of the excitation mechanism, and in fact the effect of the heavy field at the perturbed level, are cut out in the sudden transition approximation, we deduce that the above Bogoliubov coefficients are a generic feature. Not surprisingly, the same coefficents were found in [65] where inflatons in multi-field brane/anti-brane inflation decayed during inflation as the associated pairs of branes annihilate, leaving some radiation as decay products (see also [66,[71][72][73]). …”

Section: Sudden Transition Approximationmentioning

confidence: 57%

“…Since the transition takes place at a uniform φ h surface, the conditions reduce to the continuity of [65] [R]…”

Section: Matching Conditions At T * and The Power-spectrummentioning

confidence: 99%

“…2. We follow [61,65,66] to compute the resulting power-spectrum in the sudden transition approximation, see Sec. 2.3.…”

Section: Introductionmentioning

confidence: 99%

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A universal bound on excitations of heavy fields during inflation

Battefeld

Freitas

2014

J. Cosmol. Astropart. Phys.

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Abstract. We discuss a universal bound on any excitation of heavy fields during inflation: the ratio of the heavy field's energy density to the one driving inflation must be less than the maximally allowed relative amplitude of oscillations in the power-spectrum (ρ h /ρ I 0.01 according to PLANCK). This bound can be traced back to the sudden change of the equation of state parameter across the excitation event.We employ a sudden transition approximation at the perturbed level, which has been used before in different settings; we check its validity by comparison to the full multi-field result in a concrete case study involving a sudden mass change of an inflaton.

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Section: Resultssupporting

confidence: 58%

Section: Sudden Transition Approximationmentioning

confidence: 57%

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A universal bound on excitations of heavy fields during inflation

Battefeld

Freitas

2014

J. Cosmol. Astropart. Phys.

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“…An inflaton potential with a step was studied in the Einstein frame [45] (see also [46]) and shown to result in oscillations in the power spectra. Fading oscillatory features in the primordial scalar power spectrum can also occur from jumps in the potential [47][48][49][50][51], particle production during inflation [52][53][54] or turns in the inflaton trajectory in the landscape of heavy fields [55][56][57][58][59]. For a discussion of observed features in the primordial power spectrum, see for instance [60] and references therein.…”

Section: Introductionmentioning

confidence: 99%

Effect of transitions in the Planck mass during inflation on primordial power spectra

et al. 2014

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We study the effect of sudden transitions in the effective Planck mass during inflation on primordial power spectra. Specifically, we consider models in which this variation results from the non-minimal coupling of a Brans-Dicke type scalar field. We find that the scalar power spectra develop features at the scales corresponding to those leaving the horizon during the transition. In addition, we observe that the tensor perturbations are largely unaffected, so long as the variation of the Planck mass is below the percent level. Otherwise, the tensor power spectra exhibit damped oscillations over the same scales. Due to significant features in the scalar power spectra, the tensor-to-scalar ratio r shows variation over the corresponding scales. Thus, by studying the spectra of both scalar and tensor perturbations, one can constrain sudden but small variations of the Planck mass during inflation. We illustrate these effects with a number of benchmark singleand two-field models. In addition, we comment on their implications and the possibility to alleviate the tension between the observations of the tensor-to-scalar ratio performed by the Planck and BICEP2 experiments.

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The D3-$$ \overline{D}3 $$-brane inflation model revisited

Tye

2024

J. High Energ. Phys.

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Combining previous results, the D3-$$ \overline{D}3 $$ D ¯ 3 -brane pair potential U(T, ϕ) is presented here, where the inflaton ϕ measures the separation between the D3-brane and the anti-D3-brane, and the complex scalar mode T becomes tachyonic when the annihilation of the branes happens as they collide. Besides the distinct form of the inflationary potential, this hybrid inflationary model differs from a typical hybrid model in 2 important aspects: (1) U(T, ϕ) becomes complex when T becomes tachyonic, where Im U(T, ϕ) plays an important role in the dynamics towards the end of the inflationary epoch; (2) tunnelling during the inflationary epoch can happen; this is particularly relevant if there are multiple D3-$$ \overline{D}3 $$ D ¯ 3 -brane pairs in different warped throats. Besides the production of cosmic superstrings, the model offers the possibility of first order phase transition that may generate large enough density perturbation for the primordial black hole production. Stochastic gravitational wave background from these sources remain to be fully investigated.

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Brane annihilations during inflation

Cited by 25 publications

References 105 publications

A universal bound on excitations of heavy fields during inflation

A universal bound on excitations of heavy fields during inflation

Effect of transitions in the Planck mass during inflation on primordial power spectra

The D3-$$ \overline{D}3 $$-brane inflation model revisited

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