New Frontiers: Big Questions Conference I

A slow liveblog of the conference.

The New Frontiers in Astronomy and Comsology is having its awards conference at the Franklin Institute in Philadelphia.

The 20 odd winning researchers and research groups are presenting summaries of their proposed research, to be followed in a couple of years with another conference in Chicago where they will, hopefully, present their results.

The high school and college essay winners are also here to receive their awards and schmooze with the random astroboffins.

I plan to do my usual intermittent blogging of the presentations, time permitting.
The list of topics is fascinating and it will be fun to hear peoples' take on them and what approach they plan in actually, like, answering the Big Questions.

Must say, the boffins are definitely on their best behaviour, never seen a collection of scientists erring this heavily on overdressing.

First some coffee.
Then some Chernoff...

First an introduction by Don York from U Chicago who actually put this all together, for which he deserves a big thanks.

Then Jack Templeton introduces the Templeton Foundation and the motivation behind the funding of this scheme.

I. What was the earliest state of the universe?

1) Dave Chernoff on "Detecting Cosmic Superstrings"
Looking for cosmic strings stretched out from inflation, can combine with ekpyrotic models where string networks come from brane collisions mimicking classical Big Bang.
Strings stretch collide and break - get large string loops, concentrated in high density parts of the universe.

Look for deficit angle microlensing by cosmic string loops - mirror image lenses. Get quantities if detected - number density, size and string tension.

Not like old CSL-1 (not a real cosmic string lens).
This is looking for transient microlensing on minute-to-day time scales as loops traverse our line of sight.
Distinct signature from stellar/planetary microlensing, the flux doubles exactly then goes back to normal, no smooth ramp in flux.
Achromatic variability of course.

Hmmm - does pulsar glitching (or lack thereof in the peculiar way cosmic strings would glitch pulsars) put a useful upper limit on the cosmic string network? Probably not but worth thinking about.

2) Next: Mathew Holman from CMU on "CosmoArchaeology: Digging for the Initial State"

Signatures of onset of inflation.
"No real physicist tries to explain everything at once..."
Look for signatures of parametrised effective inflation theories in the CMB data.
Cosmic variance will be a confounder, as always.

and we're back:

3) Alex Maloney from McGill on "Computing the Wave Function of the Universe"

Looking at the issue of unitarity and holography in the context of cosmological evolution.

Wants to compute Hartle-Hawking wavefunction of the Universe...
solve the Wheeler-DeWitt equation in de Sitter space

interesting solution on probabilities of geometries for a toy 2+1 general relativity model

preference for highly inhomogenous states

preliminary result that complex topologies are suppressed.
Possible bound on probable complexity of topologies.
That would be very very interesting.
If it generalises, and if the physics that drives this is understood.
Reminiscent of some preliminary results in string landscape musings

Issue of observer bias - given that inflation ended (temporarily) and we exist, does that weight probabilities to homogenous initial states?

4) Parampreeet Singh from LSU - "Probing the genesis of spacetime using supercomputers"

Penrose-Hawking theorem...?
Using quantum gravity to get around cosmological singularities.

numerical loop quantum cosmology - solve quantum discrete geometry a la Ashtekar and Bojowald numerically.

mildly curious - such models bounce - avoids singularities, finite density because of irreducible volume


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