QuantumG rav ity

Tapio Salminen

Chapter 1.

Motivation

Theoretical physics

You should do things that make

you happy!

Or could it possibly be?

Have to dig a little deeper...

“Curiosity is a powerful human impulse – some distance below sex and greed, I grant you, but far ahead of altruism – and I was simply curious.”

-- Robert Harris, Ghost

Chapter 2.

Quantum gravity

QuantumG rav ity

Loops

Horavagravity

Quantumgraphity

NC QFT

Strings

The heart of the problem- Einstein's equations

Geometry = Energy

Ideas of emergent gravity

String theory

Ideas of emergent gravity

A coherent state of gravitons A coherent state of gravitons

String theory

A coherent state of gravitons

Still background dependent!

Ideas of emergent gravity

A coherent state of gravitons

Loop quantum gravity

Background independent

Problem of time

Ideas of emergent gravity

The problem of time

The problem of time

Quantum mechanics

The problem of time

General relativity

“Motion and change are primary. Nothing is, except in a very approximate and temporary sense. ... if we want to think fundamentally we must not lose sight of the essential fact that 'is' is an illusion.”

-- Lee Smolin

QuantumG rav ity

Loops

Horavagravity

Quantumgraphity

NC QFT

Strings

Chapter 3.

Quantum spacetime

Quantum theory

Quantum mechanics

Quantum oscillator

Quantum phase space

Quantum field theory

Quantum felds

and their excitations

Quantum coordinates

Quantum spacetime

Looks like it will be very complicated...

Start with a usual, commutative, quantum field theory:

Noncommutative quantum field theory

Noncommutative quantum field theory

...and insert modified products:

You will still have to check everything starting from scratch!

particles

symmetries

Interactions

causality

spin-statistics

CPT

Start checking!

So this is all just familiar calculations with a bit more math?