The mechanism is completely different from the usual string paradigm: spacetime is not introduced ab initio as a target, but emerges as the space of degree 1 worldsheet instantons in the twistor space target. ❋ Unknown (2008)
The fact that it is consistent, in not really a big point in its favor, because all the consistency is really coming from the two dimensional conformal field theory of the worldsheet. ❋ Sean (2007)
Afterwards it was discovered that the existence of fermions (something we see every day) required that the string worldsheet have supersymmetry. ❋ Sean (2007)
Any possibility that the worldsheet bosons and fermions of string theory are related to the spin networks of LQG? ❋ Sean (2007)
For example, in the bosonic string there are 26 bosonic fields which ‘live’ on the string worldsheet which are interpreted as dimensions. ❋ Sean (2007)
As strings move through time, they trace out a worldsheet similar to the worldlines of point theory. ❋ Unknown (2006)
Simple bosonic strings can be described by a field theory defined on the string worldsheet where the action is dependent upon the metric h_ {mn} on the worldsheet, the 2-curvature R_ {2} of the worldsheet, and a dilaton \phi (a scalar field on the worldsheet). ❋ Sean (2005)
If we demand that the worldsheet field theory is conformally invariant (scale invariant), then the so-called beta functions must vanish (this is necessary for us to gauge-fix the metric to the conformal gauge). ❋ Sean (2005)
If the background is curved, then it has a metric which enters the field theory on the worldsheet as a set of couplings between the string coordinates. ❋ Sean (2005)
Why do you demand that the worldsheet field theory is conformally invariant on the quantum level? ❋ Sean (2005)
So locality on the worldsheet (or being localized on the worldsheet) has nothing to do with location in spacetime. ❋ Mark (2005)
With worldsheet SUSY this disaster is avoided, one gets spectrum with no (classical linearized) instabilities. ❋ Mark (2005)
The spacetime metric appears on the worldsheet as a set of field dependent couplings of those worldsheet fields. ❋ Mark (2005)
“The worldsheet is everywhere” would in fact be a wrong answer. ❋ Mark (2005)
November 17th, 2005 at 9: 46 pm rof: - the spacetime coordinates are fields on the worldsheet. ❋ Mark (2005)
Generally worldsheet structures are invisible from the spacetime viewpoint, they are just mathematical tricks (it is unnecessarily confusing to think about string worldsheet as embedded in spacetime, as one has to sum over worldsheet metrics, where the induced metric from spacetime is only one of the metrics to be summed over). ❋ Mark (2005)
Instead, Gamma appears upon the insertion of a “vertex operator” on the worldsheet, corresponding to the string moving in a background “R-R flux”, a sort of background field in the model generated by closed strings. ❋ Cjohnson (2005)
You mentioned some specific issue to do with string worldsheet making sense only on static backgrounds (and w/o horizons) because of worldsheet SUSY. ❋ Mark (2005)
So we have to impose additional conditions to cancel the tachyon to find a worldsheet theory that could descrive the excitations of a stable ground state. ❋ Mark (2005)
