Johnson, C.V. (2003) D-Branes. Cambridge University Press, Cambridge, UK. (See in particular pages 85-87 for conformal ghosts and page 43 for negative norm states)

has been cited by the following article:

• TITLE: On the Stringy Ghosts Which We Call the Missing Dark Energy of the Cosmos

  AUTHORS: Mohamed S. El Naschie

  KEYWORDS: Quantum Spacetime, Quantum Ghost States, Dark Energy, Spacetime Cobordism, E-Infinity Theory, Fractal-Cantorian Spacetime, Noncommutative Geometry, ‘t Hooft-Susskind Holography

  JOURNAL NAME: Journal of Applied Mathematics and Physics, Vol.4 No.6, June 7, 2016

  ABSTRACT: Dark energy is explained using familiar notions and concepts used in quantum field theory, string theory and the exact mathematical theory of spacetime. The main result of the present work is first a new mathematical definition of pre-quantum spacetime (QST) as a multiset made of infinitely many empty Cantor sets connected to pre-quantum wave empty set (QW) and the pre-quantum particle (QP) zero set via the cobordism equation ∂(QW) = (QP)U(QST). Second, and in turn, this new path of reasoning is used to validate the quantum splitting of Einstein’s E = mc2 into the sum of the ordinary energy E = mc2/22 of the quantum particle and the dark energy E = mc2(21/22) of the quantum wave, used predominantly to explain the observed accelerated expansion of the universe.