arXiv subjects

P. Mansfield

Publications and source records attributed to P. Mansfield.

3 recordsLinked to original sources

arXiv2005

Timelike T-duality in the string field Schrodinger functional

Timelike T-duality of string theory appears as a symmetry of time evolution in string field theory, exchanging evolution through times t and 1/t, and exchanging boundary states with backgrounds. This is demonstrated by constructing the string field Schrodinger functional, the generator of time evolution, based on Feynman diagram arguments and in analogy with quantum field theory. There, the functional can be described using only properties of first quantised particles on a timelike orbifold. Using new sewing rules applicable to both open and closed strings we generalise this approach to bosonic string theory and express the string field Schrodinger functional in terms of strings on S^1/Z_2.

hep-th↗

arXiv1998

Finite VEVs from a Large Distance Vacuum Wave Functional

We show how to compute vacuum expectation values from derivative expansions of the vacuum wave functional. Such expansions appear to be valid only for slowly varying fields, but by exploiting analyticity in a complex scale parameter we can reconstruct the contribution from rapidly varying fields.

hep-th↗

arXiv1998

Non-perturbative VEVs from a Local Expansion

We propose a method for the calculation of vacuum expectation values (VEVs) given a non-trivial, long-distance vacuum wave functional (VWF) of the kind that arises, for example, in variational calculations. The VEV is written in terms of a Schrödinger-picture path integral, then a local expansion for (the logarithm of the) VWF is used. The integral is regulated with an explicit momentum cut-off, $Λ$. The resulting series is not expected to converge for $Λ$ larger than the mass-gap but studying the domain of analyticity of the VEVs allows us to use analytic continuation to estimate the large-$Λ$ limit. Scalar theory in 1+1 dimensions is analyzed, where (as in the case of Yang-Mills) we do not expect boundary divergences.

hep-th↗