#### Podcast Link

Ian Sample has a 38 min talk with Gerard t’Hooft about a paper he presented at EmQM2011 in Vienna. The EmQM conference is held every two years, in 2015 I presented a poster called Can a sub-quantum medium be provided by General Relativity?. He also chats with Kings College London’s Dr Eleanor Knox, for some historical perspective, and Professor Carlo Rovelli for a bit about the, relational interpretation of quantum mechanics.

Ian writes

The 20th century was a golden one for science. Big bang cosmology, the unravelling of the genetic code of life, and of course Einstein’s general theory of relativity. But it also saw the birth of quantum mechanics – a description of the world on a subatomic level – and unlike many of the other great achievements of the century, the weird world of quantum physics remains as mysterious today as it was a century ago. But what if strange quantum behaviour emerged from familiar, classical physics? How would this alter our view of the quantum world? And, more importantly, what would it tell us about the fundamental nature of reality?

Some notes while listening…

*1min* The Podcast starts off with Feynman’s guess snippet. Which is as funny as it is right.

*2min* That is followed by a very short well known (to quantum mechanics like us) intro to quantum mechanics.

*4min* Then – Ian actually uses the words ‘Emergent Quantum Mechanics’!

*5-7min* Gerard talks about the accuracy and weirdness of quantum mechanics.

*8min* Gerard – “Classical Physics is an approximation.” – not incompatible.

*8min* Ian brings out ‘God does not play dice’.

*9min* Knox – talks about the measurement problem. The collapse. The Copenhagen Interpretation.

*10min* Knox talks about emergent theories – like biology, thermodynamics. So is quantum mechanics emergent? – Will EmQM help with the measurement problem?

*13min* Gerard – perhaps the randomness of QM does arise from stochastic classical actions. The answer is no – its not classical – “its different to its bones” from classical. Its a fundamental difference. (i.e. Bell).

*15min* Gerard talks about the Standard Model of Particle Physics. – Lots of people think that is all we need.

*16min* Gerard says the SM+QM does not feel right. It lacks a certain internal logic. Gerard thinks that the laws of QM are something of an optical illusion, ‘what is it actually that we are describing’.

*17min* Gerard does not want to change the equations of QM. He keeps the equations of QM. (Tom says this is at odds with most EmQM practitioners today).

*18-22min* Ian asks if EmQM is controversial. Gerard says yes its controversial. Bell proves that its impossible to have a classical computer reproduce QM. But Gerard has looked at the small print, and finds a way around the Bell theorem – by long range correlations – linked. This correlation is the heart of QM and is not weird – but needs a natural explanation.

*22min* Ian asks if this solves ‘Spooky action at a distance’. Gerard says yes it does these correlations can explain these peculiar correlations.

*23min* Ian says Knox calls Gerards plan ‘superdeterminism’.

*25min *Ian asks why do we need to change QM if it works so well? Gerard says the positive outlook on QM as being exactly correct is the Many World Interpretation. Gerard finds MWI ‘unsatisfactory’.

26min Ian points out that Gerard and EmQM are controversial.

27min Ian talks to Carlo Rovelli.

28min Carlo says we need to get used to QM – it will not be explained or overturned soon. The weakness in EmQM’s are that they do not lead to ‘new ways of thinking’ (Tom says what??). Then he talks about String theory and QM. We should just accept it as is.

*30min* Ian talks to Gerard about being comfortable with a theory that like QM. Gerard says that the present situation is bad with the MWI multiverse. Gerard thinks that while this works its ‘unsatisfactory’.

*31min* Gerard – the MWI shows that we are not there yet. We have not found the right description for our universe. All we have today are templates – that is our description, but its not what it actually is.

*34min* Carlo – his relational theory. Which is not MWI. Take QM seriously, relational QM takes QM at face value. The properties of objects are always measured with respect to something else. Velocity is the property of an object relative to something else.

*36min* Carlo starts talking about quantum gravity. We need to use relational QM to help us get to quantum gravity.

37min Science is a long sequence of us discovering that we were wrong. The world is different. If we end up agreeing on QM then this changes realism and philosophy – which Carlo thinks that will be the case. QM is the final theory for him.