Cosmological constant in the quantum multiverse

Larsen, Grant; Nomura, Yasunori; Roberts, H. L. L.

doi:10.1103/physrevd.84.123512

Cited by 18 publications

(18 citation statements)

References 49 publications

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“…At this moment the subject is still very much in a state of flux, without clear convergence to a definitive answer. For example, using different assumptions about the measure and different ways of parametrizing observers, , De Simone et al (2008) and (Larsen et al, 2011) obtained cosmological constant distributions that peak closer to the observed value than earlier work using the Weinberg bound. The first authors used the amount of entropy produced in a causal patch as a proxy for observers.…”

mentioning

confidence: 51%

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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confidence: 51%

Life at the interface of particle physics and string theory

Schellekens

2013

Rev. Mod. Phys.

130

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“…von Bloh et al 2003;Cirkovic 2004;Vukotic & Cirkovic 2007), the rate of planetsterilizing events (Tegmark & Boström 2005) and anthropic selection biases affecting cosmological parameters (e.g. Lineweaver et al 2007;Barreira & Avelino 2011;Larsen et al 2011), whereas the distributions of planets among galaxies of different type in the local Universe and throughout the observable Universe (i.e. galaxies on our past light cone) are relevant for the prospects of SETI on extragalactic scales (e.g.…”

Section: Introductionmentioning

confidence: 99%

Terrestrial Planets Across Space and Time

Zackrisson

Calissendorff

Gonzalez

et al. 2016

ApJ

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The study of cosmology, galaxy formation and exoplanets has now advanced to a stage where a cosmic inventory of terrestrial planets may be attempted. By coupling semi-analytic models of galaxy formation to a recipe that relates the occurrence of planets to the mass and metallicity of their host stars, we trace the population of terrestrial planets around both solar-mass (FGK type) and lowermass (M dwarf) stars throughout all of cosmic history. We find that the mean age of terrestrial planets in the local Universe is 7 ± 1 Gyr for FGK hosts and 8 ± 1 Gyr for M dwarfs. We estimate that hot Jupiters have depleted the population of terrestrial planets around FGK stars by no more than ≈ 10%, and that only ≈ 10% of the terrestrial planets at the current epoch are orbiting stars in a metallicity range for which such planets have yet to be confirmed. The typical terrestrial planet in the local Universe is located in a spheroid-dominated galaxy with a total stellar mass comparable to that of the Milky Way. When looking at the inventory of planets throughout the whole observable Universe, we argue for a total of ≈ 1×1019 and ≈ 5×10 20 terrestrial planets around FGK and M stars, respectively. Due to light travel time effects, the terrestrial planets on our past light cone exhibit a mean age of just 1.7 ± 0.2 Gyr. These results are discussed in the context of cosmic habitability, the Copernican principle and searches for extraterrestrial intelligence at cosmological distances.

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“…For an explicit calculation of in the present context, see Ref. [20].) To put it simply, the multiverse lives in probability space.…”

Section: The Multiverse As a Quantum Mechanical Universementioning

confidence: 99%

Quantum Mechanics, Gravity, and the Multiverse

Nomura

2012

Astronomical Review

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The discovery of accelerating expansion of the universe has led us to take the dramatic view that our universe may be one of the many universes in which low energy physical laws take different forms: the multiverse. I explain why/how this view is supported both observationally and theoretically, especially by string theory and eternal inflation. I then describe how quantum mechanics plays a crucial role in understanding the multiverse, even at the largest distance scales. The resulting picture leads to a revolutionary change of our view of spacetime and gravity, and completely unifies the paradigm of the eternally inflating multiverse with the many worlds interpretation of quantum mechanics. The picture also provides a solution to a long-standing problem in eternal inflation, called the measure problem, which I briefly describe.

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Cosmological constant in the quantum multiverse

Cited by 18 publications

References 49 publications

Life at the interface of particle physics and string theory

Life at the interface of particle physics and string theory

Terrestrial Planets Across Space and Time

Quantum Mechanics, Gravity, and the Multiverse

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