A deeper understanding of the vacuum structure in QCD invites one to rethink certain aspects of axion physics. The recent advances are mostly due to developments in super-symmetric gauge theories and the brane theory, in which QCD can be embedded. They include, but are not limited to, the studies of metastable vacua in multicolor gluodynamics, and the domain walls. We briefly review basics of axion physics and then present a modern perspective on a rich interplay between the QCD vacuum structure and axion physics.
Bibliographical noteFunding Information:
The authors would like to thank S. Dimopoulos, A. Smilga, L. Susskind and E. Zhitnitsky for useful discussions. The work is supported by DOE grant DE-FG02-94ER408.
- Domain walls
- QCD vacuum