Axions as dark matter – a new search strategy

The dark matter of the universe probably consists of some sort of new elementary particles, although we have no specific clue as to their identity. The axion is a traditional hypothesis that is lately receiving a lot of renewed attention with many new activities. If these extremely low-mass particles are the dark matter of our galaxy, we should picture them as a kind of classical wave phenomena that can be picked up with a special antenna, producing a microwave signal. A new idea to realize this effect opens up new perspectives in our search for dark matter.