2008 : WHAT HAVE YOU CHANGED YOUR MIND ABOUT? WHY?

When journalists asked me about 20 years ago what the use of my research is, I proudly told them that it has no use whatsoever. I saw an analog to the usefulness of astronomy or of a Beethoven symphony. We don't do these things, I said, for their use, we do them because they are part of what it means to be human. In the same way, I said, we do basic science, in my case experiments on the foundations of quantum physics. it is part of being human to be curious, to want to know more about the world. There are always some of us who are just curious and they follow their nose and investigate with no idea in mind what it might be useful for. Some of us are even more attracted to a question the more useless it appears. I did my work only because I was attracted by both the mathematical beauty of quantum physics and by the counterintuitive conceptual questions it raises. So I told them all the time up to the early 1990s.

Then a new surprising development started. The scientific community discovered that the same fundamental phenomena of quantum physics suddenly became relevant for more and more novel ways of transmitting and processing of information. We now have the completely new field of quantum information science where some of the basic concepts are quantum cryptography, quantum computation and even quantum teleportation. All this points us towards a new information technology where the same strange fundamental phenomena which attracted me initially into the field are essential. Quantum randomness makes it possible for us in quantum cryptography to send messages such that they are secure against unauthorized third parties. Quantum entanglement, called by Einstein "spooky action at a distance" makes quantum teleportation possible. And quantum computation builds on all counterintuitive features of the quantum world together. When journalists ask me today what the use of my research is I proudly tell them of my conviction that we well have a full quantum information technology in the future, though its specific features are still very much to be developed. So, never say that your research is "useless".