A What are the recent advancements in quantum gravity?

[ProtonNeutron]

I am currently doing my masters in theoretical physics and I would like for my phd to be something quantum gravity oriented. However it seems hard to find what's "hot" in the field those past few years and I only know the basics of these topics (though I believe this can be improved). What are some of the relatively revent advances? Is getting into the field really worth it (asking this from a research perspective)? And if it is how do I approach this?

 

[Fractal matter]

Everyone has his own opinion on the matter. One of the most generaly accepted development is probably holographic duality.

 

[Keith_McClary]

whats "hot"

That usually means that all the easy stuff has already been done.

From an article about Werner Israel (one of my undergrad professors):

Israel’s proof became known as the “No Hair Theorem of Black Holes, with “hair” being physicists’ slang for mathematical complications. It shows only two numbers are needed to describe any black hole: its mass and its spin.“

It surprised everybody,” said Israel. “Even Stephen was surprised and very, very impressed by that paper.”

He said Hawking in one of his popular books later credited Israel with having “revolutionized black-hole physics.”

“I think he was being a little too kind,” said Israel.

He called his discovery a mixture of luck and timing. It was early on in the physicists’ examination of black holes and not many were interested.

“Back then very few people even believed in them, even Einstein didn’t believe,” said Israel. “Black holes were just too exciting.”

“So it was very good to get in at the beginning.” he said. “It was actually very easy then to make great discoveries.”

 

[ProtonNeutron]

That usually means that all the easy stuff has already been done.

Yeah that's obviously fair to say. However I still find the subject immensly interesting and compelling. I would like to examine some approaches like causal sets, causal dynamical triangulation or asymptotic safety as well as improve my general knowledge on the subject and its associated mathematics. I know this will surely be an extremely hard journey but I'm willing to take it.

 

[judiefletcher]

I would recommend that you read the following papers for an overview, and I am sure that you will find inspiration for your thesis.

String Theory

https://arxiv.org/pdf/hep-ex/0008017.pdf

Particle Physics and String Theory

https://www.nikhef.nl/~t58/RMP_Extended.pdf

String Theory and Cosmology

https://arxiv.org/pdf/1412.0579.pdf

Quantum Gravity

https://arxiv.org/pdf/0907.4238.pdf

Swampland

https://arxiv.org/pdf/2102.01111.pdf

 

[judiefletcher]

Here is a paper that suggests a way that we could indirectly detect gravitons.

https://journals.aps.org/prd/pdf/10.1103/PhysRevD.103.044017

 

[haushofer]

Maybe the way classical spacetime emerges from quantum entanglement using tensor networks? See e.g. "It from bit", Van Raamsdonk, Preskil, etc.

 

[atyy]

Some stuff like what haushofer mentioned
https://arxiv.org/abs/1812.01171
https://arxiv.org/abs/1902.10157