# HEP/Astro Seminar -- Wednesday, 21 February 2001

##
Nontopological finite temperature induced fermion number

### Abstract

Topologically nontrivial backgrounds can induce novel quantum numbers
on fermion fields. In this talk I discuss this phenomenon
at finite temperature, where some new features arise.
While the zero temperature induced fermion number in a chiral sigma model
background depends only on the asymptotic values of the chiral field,
at finite temperature the induced fermion number depends also
on the detailed shape of the chiral background. This can be interpreted
physically as the different effect of the chiral background
on virtual pairs of the Dirac sea and on the real particles
of the thermal plasma.

### References

Nontopological finite temperature induced fermion number,
I. J. R. Aitchison and G. V. Dunne,
hep-th/0006229

Finite temperature effective action in monopole background,
G. V. Dunne and J. Feinberg, Phys. Lett. **B477**, 474 (2000),
hep-th/9912195

On the finite temperature Chern-Simons coefficient,
G. V. Dunne, K. Lee and C. Liu, Phys. Rev. Lett. **78**, 3434 (1997),
hep-th/9612194

## 3:30pm, Smith Lab 1094

George T. Fleming
(
gfleming@mps.ohio-state.edu
),
last updated 27 October 2000.