Photon-propagation model with random background field: Length scales and Cherenkov limits

We present improved experimental bounds on typical length scales of a photon-propagation model with a frozen (time-independent) random background field, which could result from anomalous effects of a static, multiply connected spacetime foam.Comment: 6 pages with revtex4; v3: final versio

Lorentz-noninvariant neutrino oscillations: model and predictions

We present a three-parameter neutrino-oscillation model for three flavors of massless neutrinos with Fermi-point splitting and tri-maximal mixing angles. One of these parameters is the T-violating phase \epsilon, for which the experimental results from K2K and KamLAND appear to favor a nonzero value. In this article, we give further model predictions for neutrino oscillations. Upcoming experiments will be able to test this simple model and the general idea of Fermi-point splitting. Possible implications for proposed experiments and neutrino factories are also discussed.Comment: 22 pages, v5: final version to appear in IJMP

Possible energy-dependence of Theta_13 in neutrino oscillations

A simple three-flavor neutrino-oscillation model is discussed which has both nonzero mass differences and timelike Fermi-point splittings, together with a combined bi-maximal and trimaximal mixing pattern. One possible consequence would be new effects in \nu_{\mu} \to \nu_{e} oscillations, characterized by an energy-dependent effective mixing angle \Theta_{13}. Future experiments such as T2K and NOvA, and perhaps even the current MINOS experiment, could look for these effects.Comment: 15 pages with revtex4; title changed in journa

New Type of Traversable Wormhole

We review a new traversable-wormhole solution of the gravitational field equation of general relativity without exotic matter. Instead of having exotic matter to keep the wormhole throat open, the solution relies on a 3-dimensional "spacetime defect," which is characterized by a locally vanishing metric determinant. We also discuss the corresponding multiple-vacuum-defect-wormhole solution and possible experimental signatures from a "gas" of vacuum-defect wormholes. Multiple vacuum-defect wormholes appear to allow for backward time travel.Comment: Invited paper at Bahamas Advanced Study Institute & Conferences (BASIC), February 8-14, 2023, Stella Maris, Long Island, Bahamas. v2: final version to appear in Bulg. J. Phy

Sphalerons, spectral flow, and anomalies

The topology of configuration space may be responsible in part for the existence of sphalerons. Here, sphalerons are defined to be static but unstable finite-energy solutions of the classical field equations. Another manifestation of the nontrivial topology of configuration space is the phenomenon of spectral flow for the eigenvalues of the Dirac Hamiltonian. The spectral flow, in turn, is related to the possible existence of anomalies. In this review, the interconnection of these topics is illustrated for three particular sphalerons of SU(2) Yang-Mills-Higgs theory.Comment: 35 pages with revtex4; invited paper for the August special issue of JMP on "Integrability, topological solitons and beyond