Abstract
We provide a derivation for the particle number densities on phase space for scalar and fermionic fields in terms of Wigner functions. Our expressions satisfy the desired properties: for bosons the particle number is positive, for fermions it lies in the interval between zero and one, and both are consistent with thermal field theory. As applications we consider the Bunch-Davies vacuum and fermionic preheating after inflation.
| Original language | English |
|---|---|
| Pages (from-to) | 135-143 |
| Number of pages | 9 |
| Journal | European Physical Journal C |
| Volume | 38 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2004 |
| Externally published | Yes |