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Andy Strominger's 74 questions

While at Strings 2014, Clifford Johnson particularly liked one of the "visions talk", the talk by Andy Strominger.

Quantum Gravity and String Theory
Andy gave a realistic i.e. enthusiastic summary of the last three decades in the research of stringy quantum gravity. Most of the advances couldn't have been guessed 30 years ago, Andy observes, and "it is a mistake in science to imagine that you ever know the limits of what we can see", Andy quotes John Kovacs, the BICEP2 boss, who said it at the March 2014 Harvard colloquium.

The amount of progress in the last 30 years really looks impressive with the hindsight.

Andy has also sent e-mails to all speakers at Strings 2014 and/or physicists who were sufficiently important for the conference. Their task was to send a short "interest question" that should be answered by the future research, and perhaps a hint.

He has received 74 contributions. Most of them are closely linked to some of the proponents' recent papers – so some of them are not so impartial advertisements of some of the technical and perhaps "not everlasting" research that was done. But if you look at the questions statistically, you will see that there are lots of questions that are really deep and interesting – yet accessible to doable research that actually has a high chance to nail the questions down.

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reader Michael said...

Interesting. It seems Polchinski's question, however, has long since been answered on this blog and elsewhere.

reader Leo Vuyk said...

May I reduce the number to 9x qustions and change some?

1: Is Dark Matter the same as Black Holes of all sizes which consume photons and
gravitons, repel fermions and have negative electric potential at the outside
and positive potential at the inside?
2: Is Dark Energy the same as the oscillating Higgs Field with Casimir push effect and
push- gravity potential?.
3: Is Quantum Gravity based on a dual Casimir-Graviton push system ? (Higgs-Casimir
push opposing Graviton push= attraction?).
4: Is the Big Bang a symmetric (entangled matter- anti-matter-multiverse ) splitting Dark
Matter Black Hole (DM-BH) into smaller primordial DM-BH Splinters and
evaporating into the oscillating Dark Energy Higgs field.
5: Is the Big Bang self organizing and quiet inflating, by the splitting and pairing
DM-BHs which could be able in succession to produce all the universal plasma
and dual BH based Herbig Haro systems as a base for stars in open star clusters
and as a start for Spiral Galaxies and the Lyman Alpha forest?
6: Is the dual DM-BH based spiral galaxy able to merge with other spirals to form
elliptical systems and are the DM-BHs able to anchor the galaxy in the middle
and coined: Galaxy Anchor Black Holes ( GABHs)?
7: Is a GABH still able to form pairs and produce plasma after Galaxy Merging and
create Dwarf galaxies in between, but outside the main galaxy?
8: Is a sub-quantum structure of elementary particles able to explain all particle
decay trajectories and the repulsion of fermions at the black hole horizon by
so called spin flip?
9: Is the vacuum structure chiral and responsible for the fact that we live inside a
material bubble of the (CP) symmetric multiverse?
(questions are related to Quantum FFF Theory ( Function Follows Form)

reader Giotis said...

Apparently Susskind is seeing something deep in computational complexity.

Is this really the case?

I don’t have a clue but I have the feeling there will be a popular book on the subject.

reader Gordon said...

If Strominger ever abandons physics, he could sell his
artwork to the Pompidou Centre :)

reader Alfred J. said...


Could you take a shot at explaining emergent space/time and also how QM might be emergent?

reader Luboš Motl said...

LOL, Andy has four daughters and he is very playful with them but because I've seen the girls and it's some time ago, the pictures make it look like Andy must have new children. Fifth, sixth etc. ;-)

reader Luboš Motl said...

He's certainly into it in recent years.

reader Luboš Motl said...

Just to repeat, he asks whether old black holes have smooth horizons. "The answer must be justified by a quantum gravity defined from first principles."

This is a very subtle thing. If we want a "constructive" definition from the first principles, we must use specific enough definitions of string/M-theory, and indeed, they don't "directly" tell us anything about the black hole interior.

But quantum gravity with this name - quantum gravity as opposed to string theory - is supposed to be defined as a consistent reconciliation of QM/QFT and GR, and yes, I would argue that in particular Raju+Papadodimas' answer is exactly what Joe is asking about then.

reader Luboš Motl said...

Quantum mechanics is exact, so it is not emergent. That doesn't mean that we won't ever understand why it is what it is in some more unified way but it does mean that the postulates that were formulated in the 1920s will never really break down.

Explaining emergent spacetime is like explaining most of the modern string theory research, and I did it in many blog posts before.

reader Gordon said...

Hmm, that explains it. Either he contracted with new infants to do his illustrations, or else he got a pet
(Note: the artwork, though, is superior to my efforts...)

reader JollyJoker said...

You probably both know which question this was about, but just because I looked it up:

30. Question: What is time and how does quantum mechanics emerge?
Hint: Given that space is emergent so should time. Since it's hard to formulate QM without time, QM itself should be an emergent theory.

(Nathan Seiberg)

I'm reminded of some Nima A-H talk where he suggested (iirc) that QM could be extended; probably something related to the scattering -without-spacetime work.

reader tomandersen said...

trolling, or has not looked at Lubos' recent articles on the subject.

reader Giotis said...

Finally some of the videos are now online!

BTW I don't like the expression used by Strominger:

"...anything could lie ahead".

What does this mean? It implies that people don't have a clue and we have not learned anything from ST and other established theories.

IMHO this expression is wrong and misleading.

reader Luboš Motl said...

I understand where you're coming from but I agree with Andy. What "lies ahead" explicitly refers to future discoveries in the field which are obviously unknown. Things that are already understood are not lying ahead of us; they are behind us in this language, aren't they?

reader Dilaton said...

Haha, Andy Strominger s hand written slides and amusing drawings are a lot of fun :-D, they convey the impression that even though doing very serious work, string theorists are a bunch of cool funny likable people with a good portion of nicely geeky humor ...

And be warned sifting through the exciting questions make me feel very tempted to steel them for certain purposes ...;-)

Yes I know that I am late to this party but finally I am here and had fun anyway :-P