Contents

spin geometry

string geometry

# Contents

## Idea

The Velo-Zwanziger problem is is a phenomenon in theoretical physics: the “evident” action functionals for fields which

1. have spin higher than 1

2. are in an irreducible massive representation of the Lorentz group

tend to have equations of motion which are not hyperbolic and hence may violate the usual causality relation of general relativity.

## References

The original references are

• G. Velo, D. Zwanziger, Phys. Rev. 186 (1969) 1337,

• G. Velo, D. Zwanziger, Phys. Rev. 188 (1969) 2218;

• G. Velo, Nucl. Phys. B 43 (1972) 389

• M. Hortacsu, Phys. Rev. D 9, 928 (1974).

Adjustments of the action functional for spin massive $3/2$-particles (Rarita-Schwinger field) by non-minimal coupling that evades the Velo-Zwanziger problem is discussed in

• Massimo Porrati, Rakibur Rahman, Causal Propagation of a Charged Spin 3/2 Field in an External Electromagnetic Background, Phys.Rev.D80:025009,2009 (arXiv:0906.1432)

Discussion for the higher string excitations that appear in string theory is for instance in

• Massimo Porrati, Rakibur Rahman, Augusto Sagnotti, String Theory and The Velo-Zwanziger Problem, Nucl. Phys. B846:250-282,2011 (arXiv:1011.6411)

Last revised on June 10, 2014 at 04:06:41. See the history of this page for a list of all contributions to it.