Populating the Whole Landscape

Brown, Adam R.; Dahlen, Alex

doi:10.1103/physrevlett.107.171301

Cited by 36 publications

(44 citation statements)

References 23 publications

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“…This would erase all memory of the initial conditions. Furthermore Brown and Dahlen (2011) have argued that despite some potential problems -vacua not connected by instantons, or only connected through sinks (Clifton et al, 2007) -all dS vacua are reachable with non-zero transition rates. This result holds for minima of the same potential, but arguments were given for parts of the landscape with different topologies as well.…”

Section: The Dominant Vacuummentioning

confidence: 99%

Life at the interface of particle physics and string theory

Schellekens

2013

Rev. Mod. Phys.

130

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If the results of the first LHC run are not betraying us, many decades of particle physics are culminating in a complete and consistent theory for all non-gravitational physics: the Standard Model. But despite this monumental achievement there is a clear sense of disappointment: many questions remain unanswered. Remarkably, most unanswered questions could just be environmental, and disturbingly (to some) the existence of life may depend on that environment. Meanwhile there has been increasing evidence that the seemingly ideal candidate for answering these questions, String Theory, gives an answer few people initially expected: a huge "landscape" of possibilities, that can be realized in a multiverse and populated by eternal inflation. At the interface of "bottomup" and "top-down" physics, a discussion of anthropic arguments becomes unavoidable. We review developments in this area, focusing especially on the last decade.

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Section: The Dominant Vacuummentioning

confidence: 99%

Life at the interface of particle physics and string theory

Schellekens

2013

Rev. Mod. Phys.

130

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“…After emerging, the field will roll down the potential until the next minimum. This process allows to connect minima for which a CDL instanton does not exist, and has been argued to be essential to populate the landscape [48], since up-tunneling from AdS cannot proceed through usual CDL instantons. The decay rate of this stochastic diffusion process is equivalent to that of an homogeneous tunneling of the whole universe in which the bubble radius is R b ∼ l 4 .…”

Section: Jhep11(2017)066mentioning

confidence: 99%

“…[44][45][46][47][48] and references therein). A HM instanton describes the quantum transition of a field starting at the minimum and emerging at the top of the barrier due to quantum fluctuations in a sort of Brownian motion [46][47][48]. After emerging, the field will roll down the potential until the next minimum.…”

Section: Jhep11(2017)066mentioning

confidence: 99%

Constraining neutrino masses, the cosmological constant and BSM physics from the weak gravity conjecture

Ibáñez

Lozano²,

Valenzuela

2017

J. High Energ. Phys.

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It is known that there are AdS vacua obtained from compactifying the SM to 2 or 3 dimensions. The existence of such vacua depends on the value of neutrino masses through the Casimir effect. Using the Weak Gravity Conjecture, it has been recently argued by Ooguri and Vafa that such vacua are incompatible with the SM embedding into a consistent theory of quantum gravity. We study the limits obtained for both the cosmological constant Λ 4 and neutrino masses from the absence of such dangerous 3D and 2D SM AdS vacua. One interesting implication is that Λ 4 is bounded to be larger than a scale of order m 4 ν , as observed experimentally. Interestingly, this is the first argument implying a non-vanishing Λ 4 only on the basis of particle physics, with no cosmological input. Conversely, the observed Λ 4 implies strong constraints on neutrino masses in the SM and also for some BSM extensions including extra Weyl or Dirac spinors, gravitinos and axions. The upper bounds obtained for neutrino masses imply (for fixed neutrino Yukawa and Λ 4 ) the existence of upper bounds on the EW scale. In the case of massive Majorana neutrinos with a see-saw mechanism associated to a large scale M 10 10−14 GeV and Y ν 1 10 −3 , one obtains that the EW scale cannot exceed M EW 10 2 − 10 4 GeV. From this point of view, the delicate fine-tuning required to get a small EW scale would be a mirage, since parameters yielding higher EW scales would be in the swampland and would not count as possible consistent theories. This would bring a new perspective into the issue of the EW hierarchy.

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“…Domain walls between stable de Sitter vacua trigger an instability towards nonpositive vacuum energy [18][19][20][21][22][23].…”

Section: Jhep12(2016)155mentioning

confidence: 99%

“…Therefore, the presence of a domain wall between metastable vacua will generically de-stabilize some moduli, as illustrated in figure 1. The instability towards a runaway phase leads to the collapse of the interior de Sitter vacuum and naively poses an obstacle to populating the landscape [19][20][21][22][23].…”

Section: Jhep12(2016)155mentioning

confidence: 99%

Inflation expels runaways

Bachlechner

2016

J. High Energ. Phys.

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We argue that moduli stabilization generically restricts the evolution following transitions between weakly coupled de Sitter vacua and can induce a strong selection bias towards inflationary cosmologies. The energy density of domain walls between vacua typically destabilizes Kähler moduli and triggers a runaway towards large volume. This decompactification phase can collapse the new de Sitter region unless a minimum amount of inflation occurs after the transition. A stable vacuum transition is guaranteed only if the inflationary expansion generates overlapping past light cones for all observable modes originating from the reheating surface, which leads to an approximately flat and isotropic universe. High scale inflation is vastly favored. Our results point towards a framework for studying parameter fine-tuning and inflationary initial conditions in flux compactifications.

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Populating the Whole Landscape

Abstract: Every de Sitter vacuum can transition to every other de Sitter vacuum despite any obstacle, despite intervening anti-de Sitter sinks, despite not being connected by an instanton. Eternal inflation populates the whole landscape.

Cited by 36 publications

References 23 publications

Life at the interface of particle physics and string theory

Life at the interface of particle physics and string theory

Constraining neutrino masses, the cosmological constant and BSM physics from the weak gravity conjecture

Inflation expels runaways

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