Silence of the Lambda? Farewell, dark energy?

[foghorn]

Are there any attempts at making those models?

I take it that it would be around the time T+10^-43 seconds?

Are there any forces at work then that might apply?

Yes the Planck time when equations start forming infinities going further back in time.

I’m no expert, but for what I do think I ‘understand’…
Einstein’s GR becomes unusable because of singularities forming in the equations at such early times.
If you remember GR is a geometrical modelling of spacetime events which form a manifold.

Well, to stop spacetime modelling becoming a singularity(unusable) at such densities and energies present at these early periods in the universe, there is a need for a model for the quantisation of spacetime.
And such a quantum model of spacetime would allow a ‘deeper’ back in time probe.

The ‘model’ Loop quantum gravity is an attempt at that quantisation of spacetime.
I think

 

[Pinball1970]

quantisation of spacetime.

Above my pay grade. From what I have read regarding supergravity, QLG, string Theory on some of the other discussion forums, usually in the "Beyond the standard model" sections, things have not moved on that much.
Leonard Susskind one of the fathers of String Theory practically admitted defeat on this. Strings have failed.
There is certainly no experimental evidence from particle accelerators regarding supersymmetric particles or extra dimensions.
I read an abstract from a paper that started, "it is safe to say we as yet do not have a working theory of quantum gravity"
The author? Stephen Hawking.
The year, 1975. Fifty years and no further forward. Perhaps they have ruled some things out?
The experimental stuff seems to be the driving force right now while the theorists catch up.
Regarding the cosmos that is, we are in a golden era of data from ground based and space telescopes.
Gaia is being retired to make way for superior instruments, things must be getting congested at L2!
Data from there is said to be enough till 2030!
That is with the current computer technology available, with the growth of AI and possibilities with Quantum computers who knows?