Three Roads To Quantum Gravity

236 THREE ROADS TO QUANTUM GRAVITY
REFERENCE TO THE SCIENTIFIC LITERATURE
........................................................................
Virtually the whole of the scienti®c literature on topics relevant to
theoretical physics since 1991 is available in an electronic archive,
which can be found at http://xxx.lanl.gov/. Note that while you
generally have to have a professional af®liation to publish at this site,
anyone can download and read the articles archived there. The papers
of relevance to this book are mostly found in the archives hep-th and grqc.
A search for the people mentioned below will return a list of the
papers which underlie the developments described.
Another very good source for the ideas and mathematical developments
used in quantum gravity is John Baez's Website, This Week's
Finds in Mathematical Physics, at http://math.ucr.edu/home/baez/
TWF.html. He also has a nice online tutorial introduction to general
relativity at http://math.ucr.edu/home/baez/gr/gr.html. The reader
wanting a general introduction to the history of quantum gravity and
its basic issues may ®nd the following articles interesting: Carlo
Rovelli, `Notes for a brief history of quantum gravity', gr-qc/0006061;
Carlo Rovelli, `Quantum spacetime ± what do we know?', gr-qc/
9903045, and Lee Smolin, `The new universe around the next corner',
in Physics World, December 1999.
Most of the following key references are in the xxx.lanl.gov archive. A
more complete list of references is available at the Website mentioned
above.
CHAPTER 2
The discussion of the logic of observers inside the universe is based on
F. Markopoulou, `The internal description of a causal set: What the
universe looks like from the inside', gr-qc/9811053, Commun. Math.
Phys. 211 (2000) 559±583.
CHAPTER 3
The consistent histories interpretation is described in R.B. Grif®ths,
Journal of Statistical Physics 36 (1984) 219; R. Omnes, Journal of
Statistical Physics 53 (1988) 893; and M. Gell-Mann and J.B. Hartle in
Complexity, Entropy, and the Physics of Information, SFI Studies in the
Sciences of Complexity, Vol. VIII, edited by W. Zurek (Addison Wesley,
Reading, MA, 1990). The criticisms of Kent and Dowker are found in
Fay Dowker and Adrian Kent, `On the consistent histories approach to
quantum mechanics', Journal of Statistical Physics. 82 (1996) 1575.
Gell-Mann and Hartle comment in `Equivalent sets of histories and
multiple quasiclassical realms', gr-qc/9404013; J. B. Hartle, gr-qc/