Multiverse in Karch-Randall Braneworld: Application to Grandfather Paradox

Table of Links

Abstract & Introduction

Brief Review of Wedge Holography

Emerging Multiverse from Wedge Holography

Application to Information Paradox

Application to Grandfather Paradox

Conclusion

Acknowledgements and References

5 Application to Grandfather Paradox

This section states the “grandfather paradox” and its resolution in our setup.

“Grandfather paradox” says that Bob can not travel back in time. Because if he can travel back in time, he can land in another universe where he can kill his grandfather. If Bob’s grandfather is dead in another universe, then he will not exist in the present [61].

Now let us see how this problem can be avoided in our setup. We discussed in sections 3.1 and 3.2 that a multiverse consists of 2n Karch-Randall branes, which we call “universes”. The geometry of these branes is AdS and de-Sitter spacetime in sections 3.1 and 3.2. In all the setups, all “universes” are connected at the “defect” via transparent boundary condition. Transparent boundary condition guarantees that all these universes are communicating with each other.

Suppose Bob lives on Q1 and his grandfather lives on Q2. Then to avoid the paradox, Bob can not travel to Q2, but he can travel to Q−2, Q−3 etc. where he can meet Robert and Alice. Hence “grandfather paradox” can be resolved in this setup. Further traversable wormhole solution is also possible [63]. This discussion is consistent with “many world theory” where “grandfather paradox” has been resolved using the similar idea.