Browsing by Author "Potting, R."

Now showing 1 - 7 of 7

Analytical construction of a nonperturbative vacuum for the open bosonic string
(American Physical Society, 2001) Kostelecký, V.A.; Potting, R.
Using analytical methods, a nonperturbative vacuum is constructed recursively in the field theory for the open bosonic string. Evidence suggests it corresponds to the Lorentz-invariant end point of tachyon condensation on a D25-brane. The corresponding string field is a twisted squeezed state.
$CPT$, strings, and meson factories
(American Physical Society, 1995) Kostelecký, V.A.; Potting, R.
Spontaneous breaking of $CPT$ is possible in string theory. We show that it can arise at a level within reach of experiments at meson factories currently being built or designed. For $\varphi$, $B$, and $\tau$-charm factories, we discuss the likely experimental string signatures and provide estimates of the bounds that might be attained in these machines.
Expectation values, Lorentz invariance, and $\text{CPT}$ in the open bosonic string
(Physics Letters B, 1996) Potting, R.; Kostelecký, V.A.
The issue of spontaneous breaking of Lorentz and $\text{CPT}$ invariance is studied in the open bosonic string using a truncation scheme to saturate the string-field action at successively higher levels. We find strong evidence for the existence of extrema of the action with nonzero expectation values for certain fields. The Lorentz- and $\text{CPT}$-preserving solution previously suggested in the literature is confirmed through level 12 in the action. A family of Lorentz-breaking, $\text{CPT}$-preserving solutions of the equations of motion is found to persist and converge through level 18 in the action. Two sequences of solutions spontaneously breaking both Lorentz invariance and $\text{CPT}$ are discussed. The analysis at this level involves the analytical form of over 20,000 terms in the static potential.
Gravity from spontaneous Lorentz violation
(American Physical Society, 2009) Kostelecký, V.A.; Potting, R.
We investigate a class of theories involving a symmetric two-tensor field in Minkowski spacetime with a potential triggering spontaneous violation of Lorentz symmetry. The resulting massless Nambu-Goldstone modes are shown to obey the linearized Einstein equations in a fixed gauge. Imposing self-consistent coupling to the energy-momentum tensor constrains the potential for the Lorentz violation. The nonlinear theory generated from the self-consistent bootstrap is an alternative theory of gravity, containing kinetic and potential terms along with a matter coupling. At energies small compared to the Planck scale, the theory contains general relativity, with the Riemann-spacetime metric constructed as a combination of the two-tensor field and the Minkowski metric. At high energies, the structure of the theory is qualitatively different from general relativity. Observable effects can arise in suitable gravitational experiments.
Off-shell structure of the string sigma model
(American Physical Society, 2000) Kostelecký, V.A.; Perry, M.J.; Potting, R.
The off-shell structure of the string sigma model is investigated. In the open bosonic string, nonperturbative effects appear to depend crucially on the regularization scheme. A scheme retaining the notion of string width reproduces the structure of Witten's string field theory.
$\text{CPT}$ Violation and Baryogenesis
(Physics Letters B, 1997) Bertolami, O.; Colladay, Don; Kostelecký, V.A.; Potting, R.
We examine the effects on baryogenesis of spontaneous $\text{CPT}$ violation in a string-based scenario. Under suitable circumstances, certain $\text{CPT}$-violating terms can produce a large baryon asymmetry at the grand-unified scale that reduces to the observed value via sphaleron or other dilution mechanisms.
$\text{CPT}$ violation and baryogenesis
(Physics Letters B, 1997) Bertolami, O.; Colladay, Don; Kostelecký, V.A.; Potting, R.
We examine the effects on baryogenesis of spontaneous $\text{CPT}$ violation in a string-based scenario. Under suitable circumstances, certain $\text{CPT}$-violating terms can produce a large baryon asymmetry at the grand-unified scale that reduces to the observed value via sphaleron or other dilution mechanisms.