# Three Impossible Theories

@inproceedings{Susskind2021ThreeIT, title={Three Impossible Theories}, author={Leonard Susskind}, year={2021} }

I will begin by conjecturing a cosmological generalization of black hole complementarity (also known as the central dogma). I will then discuss three theories and argue that they are inconsistent with second law of thermodynamics if the cosmological version of the dogma is correct. The three theories are: the big rip; cyclic cosmology; and the Farhi-Guth-Guven mechanism for creating inflating universes behind black hole horizons. ar X iv :2 10 7. 11 68 8v 1 [ he pth ] 2 4 Ju l 2 02 1

## 7 Citations

### The central dogma and cosmological horizons

- PhysicsJournal of High Energy Physics
- 2022

The central dogma of black hole physics — which says that from the outside a black hole can be described in terms of a quantum system with exp(Area / 4 G N ) states evolving unitarily — has recently…

### Encoding beyond cosmological horizons in de Sitter JT gravity

- Physics
- 2022

Black hole event horizons and cosmological event horizons share many properties, making it natural to ask whether our recent advances in understanding black holes generalize to cosmology. To this…

### A heuristic approach to the far-future state of a universe dominated by phantom energy

- Physics
- 2022

This work is based on a cosmological scenario of a universe dominated by phantom energy with equation of state parameter w < −1 and the analysis of its asymptotic behaviour in the far-future. The…

### The grand canonical Multiverse and the small cosmological constant

- PhysicsJournal of Cosmology and Astroparticle Physics
- 2022

We consider the Multiverse as an ensemble of universes. Using standard statistical physics analysis we get that the Cosmological Constant (CC) is exponentially small. The small and finite CC is…

### A mechanism of baryogenesis for causal fermion systems

- PhysicsClassical and Quantum Gravity
- 2022

It is shown that the theory of causal fermion systems gives rise to a novel mechanism of baryogenesis. This mechanism is worked out computationally in globally hyperbolic spacetimes in a way which…

### A Tail of Eternal Inflation

- Physics
- 2021

Non-trivial inflaton self-interactions can yield calculable signatures of primordial nonGaussianity that are measurable in cosmic surveys. Surprisingly, we find that the phase transition to slow-roll…

### A Local Wheeler-DeWitt Measure for the String Landscape

- Physics
- 2022

According to the ‘Cosmological Central Dogma’, de Sitter space can be viewed as a quantum mechanical system with a ﬁnite number of degrees of freedom, set by the horizon area. We use this assumption…

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