# Toward inflation models compatible with the no-boundary proposal

@article{Hwang2014TowardIM, title={Toward inflation models compatible with the no-boundary proposal}, author={Dong-il Hwang and Dong-han Yeom}, journal={Journal of Cosmology and Astroparticle Physics}, year={2014}, volume={2014}, pages={007 - 007} }

In this paper, we investigate various inflation models in the context of the no-boundary proposal. We propose that a good inflation model should satisfy three conditions: observational constraints, plausible initial conditions, and naturalness of the model. For various inflation models, we assign the probability to each initial condition using the no-boundary proposal and define a quantitative standard, typicality, to check whether the model satisfies the observational constraints with probable…

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## References

SHOWING 1-10 OF 90 REFERENCES

### No-boundary measure and preference for large e-foldings in multi-field inflation

- Physics
- 2013

The no-boundary wavefunction of quantum gravity usually assigns only very small probability to long periods of inflation. This was a reason to doubt about the no-boundary wavefunction to explain the…

### No-boundary measure of the universe.

- MathematicsPhysical review letters
- 2008

The no-boundary proposal for homogeneous isotropic closed universes with a cosmological constant and a scalar field with a quadratic potential predicts classical behavior at late times if the scalarField is large enough.

### Hartle–Hawking no-boundary proposal in dRGT massive gravity: making inflation exponentially more probable

- Physics
- 2013

It is known that the no-boundary proposal in the traditional Einstein gravity does not prefer inflation, that is, the probability of realizing a large number of e-folds is exponentially suppressed.…

### Multiple Inflationary Stages with Varying Equation of State

- Physics
- 2012

We consider a model of inflation consisting a single fluid with a time-dependent equation of state. In this phenomenological picture, two periods of inflation are separated by an intermediate…

### Why does inflation start at the top of the hill

- Physics
- 2002

We show why the universe started in an unstable de Sitter state. The quantum origin of our universe implies one must take a ``top down'' approach to the problem of initial conditions in cosmology, in…

### Planck 2015. XX. Constraints on inflation

- Physics
- 2015

We analyse the implications of the Planck data for cosmic inflation. The Planck nominal mission temperature anisotropy measurements, combined with the WMAP large-angle polarization, constrain the…

### Populating the landscape: A Top down approach

- Physics
- 2006

We put forward a framework for cosmology that combines the string landscape with no boundary initial conditions. In this framework, amplitudes for alternative histories for the universe are…

### Prescription for successful new inflation

- Physics
- 1984

The conditions on the effective (de Sitter space) scalar potential that are required to obtain a successful new-inflationary-Universe scenario are codified into a general prescription. These…

### Susskind’s challenge to the Hartle–Hawking no-boundary proposal and possible resolutions

- Physics
- 2007

Given the observed cosmic acceleration, Leonard Susskind has presented the following argument against the Hartle–Hawking no-boundary proposal for the quantum state of the universe: it should most…