DBI realizations of the pseudo-conformal universe and Galilean Genesis scenarios

Hinterbichler, Kurt; Joyce, Austin; Khoury, Justin; Miller, Godfrey E. J.

doi:10.1088/1475-7516/2012/12/030

Cited by 84 publications

(96 citation statements)

References 162 publications

(316 reference statements)

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“…The galileons have been used to address cosmic acceleration [516][517][518][519][520][521][522][523][524][525] and the origin of density perturbations in the early universe through inflation [526][527][528][529][530][531][532][533][534][535][536] and inflationary alternatives [537][538][539][540][541][542][543][544][545]. They have also been used to violate the null energy condition [537,[544][545][546][547][548][549][550][551][552][553].…”

Section: The Vainshtein Mechanism: Galileonsmentioning

confidence: 99%

Beyond the cosmological standard model

et al. 2015

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After a decade and a half of research motivated by the accelerating universe, theory and experiment have a reached a certain level of maturity. The development of theoretical models beyond Λ or smooth dark energy, often called modified gravity, has led to broader insights into a path forward, and a host of observational and experimental tests have been developed. In this review we present the current state of the field and describe a framework for anticipating developments in the next decade. We identify the guiding principles for rigorous and consistent modifications of the standard model, and discuss the prospects for empirical tests.We begin by reviewing recent attempts to consistently modify Einstein gravity in the infrared, focusing on the notion that additional degrees of freedom introduced by the modification must "screen" themselves from local tests of gravity. We categorize screening mechanisms into three broad classes: mechanisms which become active in regions of high Newtonian potential, those in which first derivatives of the field become important, and those for which second derivatives of the field are important. Examples of the first class, such as f (R) gravity, employ the familiar chameleon or symmetron mechanisms, whereas examples of the last class are galileon and massive gravity theories, employing the Vainshtein mechanism. In each case, we describe the theories as effective theories and discuss prospects for completion in a more fundamental theory. We describe experimental tests of each class of theories, summarizing laboratory and solar system tests and describing in some detail astrophysical and cosmological tests. Finally, we discuss prospects for future tests which will be sensitive to different signatures of new physics in the gravitational sector.The review is structured so that those parts that are more relevant to theorists vs. observers/experimentalists are clearly indicated, in the hope that this will serve as a useful reference for both audiences, as well as helping those interested in bridging the gap between them.

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Section: The Vainshtein Mechanism: Galileonsmentioning

confidence: 99%

Beyond the cosmological standard model

et al. 2015

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“…[48,69,70,49,50,71]). One assumes that at early times t → −∞, the space-time is Minkowskian, energy and pressure vanish, the Universe is empty.…”

Section: Genesis Scenariomentioning

confidence: 99%

“…As we discuss in Section 3, there exist finite number of classes of second-derivative Lagrangians yielding second-derivative field equations [33,44,45,46]. At least some of these Lagrangians admit NEC-violation [47,48,49,50,51,52], with the NEC-violating solutions and their neighborhoods being perfectly healthy. In Section 4 we give a few examples of using these theories for constructing fairly non-trivial cosmological models and giving a proof-of-principle construction for creating a universe in the laboratory.…”

Section: Introductionmentioning

confidence: 99%

The null energy condition and its violation

2014

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“…There is an alternative to inflation, in which the primordial universe is slowly expanding, i.e. genesis scenario [20], [21], [22], also earlier [23], see [24] for a review. In this scenario, n T = 2, thus its tensor amplitude is exponentially low at large scale, which is negligible.…”

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confidence: 99%

“…Initially |t| ≫ |t * | and M b (t * − t) b ≫ 1, the universe is slowly expanding [20], [21], [22], see [31], [32] for alternatives. Here,…”

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confidence: 99%

Preinflationary genesis with CMB B-mode polarization

Liu

Li²,

Piao³

2014

Phys. Rev. D

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Recent B-mode polarization observation seems to imply the tensor tilt n T 1 at large angular scale, if the primordial signal is dominated. We show that for a primordial universe, which is in a slowly expanding genesis phase before the slow-roll inflation, the primordial tensor spectrum will get a large-scale cutoff, i.e. n T 1 at large scales while n T ≃ 0 at small scale. We find that this inflationary scenario not only may be consistent with the observation, but also predicts a large-scale anomaly in BB power spectrum, i.e. due to the large suppression of tensor perturbation amplitude we will hardly see the reionization bump at low-l, which may be falsified by the Planck polarization data.

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DBI realizations of the pseudo-conformal universe and Galilean Genesis scenarios

Cited by 84 publications

References 162 publications

Beyond the cosmological standard model

Beyond the cosmological standard model

The null energy condition and its violation

Preinflationary genesis with CMB B-mode polarization

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