What is ‘trans-Planckian’ physics?
Thanks for the thoughtful comments Paul. While “trans-Planckian” physics is essentially a placeholder for whatever physics replaces current physics at the Planck scale and below, I think the ideas of Volovik and others, outlined in my post, could be a fruitful starting point. The matter and fields that we perceive could be like music generated by a trans-Planckian material reality that we don’t perceive yet.
As you say, the holographic principle, and higher-dimensional string theories with branes and all that, are another useful starting point. I started to cover this ground in “Simulation physics and theology for Qubitzers.” I suspect these two approaches, starting from respectively condensed matter analogies and string theories, could turn out to be strongly related.
I think hidden variables don’t contradict experimental evidence if they operate non-locally (e.g. non-local pilot waves, Nelson’s quantum fluctuations etc.), and both approaches to trans-Planckian physics above could be formulated in terms of non-local hidden variables.
In both cases, quantum physics is still fundamental, and I guess our current understanding of quantum physics isn’t good enough yet. I think your “entangled with states of matter that we have no current access to” could be a very useful concept.
I don’t understand your last point about alternate dimensions, could you elaborate?