Perspectives in string theory? L.Bonora SISSA,Trieste, Italy Belgrade, September 2012
Jan 28, 2016
Perspectives in string theory?
L.Bonora
SISSA,Trieste, Italy
Belgrade, September 2012
Prologue
We have good reasons to believe that there is ‘life’ beyond the standard model:
• dark energy
• dark matter
• inflation
• neutrino mass
• theoretical arguments….
What is beyond the SM?
• Grand unification• Supersymmetry• Supergravity / quantum gravity........... but certainly a renormalizable gauge field theory,
which means UV completeness
- and then ..... superstring theory which offers quantum gravity and UV compleness
….but what string theory?
• At present there are superstring / M-theory in 10/11 D. These theories are formulated perturbatively
• These theories are connected by s- and t-dualities
• There is no unique formulation.
A complete string theory can only be a string field theory
• We have Open Bosonic String Field Theory (à la Witten). It works
• Closed Bosonic SFT (not a field theory)
• Superstring FT’s (incomplete)
Summary
Review of SFT Exact solutions Dp-brane solutions Open-closed duality Prospects: fermions, supersymmetry (based on work done in collaboration with S.Giaccari,
C.Maccaferri, D.D.Tolla)
z z
Prospects
and
Conjectures
Open-closed string duality
D-branes can be expressed in terms of open strings (background independence)
Perturbative closed string states are they limits of S-branes?
Is there a unique string theory, rather than two?
Closed ST does not seem to be a field theory.
Is open SFT the fundamental theory?
Open SFT fundamental?
• It is unstable – is this important?
• It has a tachyon , perhaps two – so what?
• It does not contain gravity – gravity is effective
• It doesn’t contain fermions – this is worrying but not tragic, because….
D=26 or D=10 ?
• 26 = 10 + 16
• Fermions from bosons (old idea)
• Fermions exact solutions of bosonic SFT
• Susy as enhanced symmetry
• SSFT as effective theory of bosonic SFT
• Re-design the landscape….
THANKS