What physicists want to know

Last week, Canada's esteemed Perimeter Institute for Theoretical Physics hosted its big vision conference Quantum to Cosmos. One panel revolved around the question, "What keeps you awake at night?" New Scientist synthesized the seven big questions that emerged from the discussion. Here are two biggies:
How does complexity happen? From the unpredictable behaviour of financial markets to the rise of life from inert matter, Leo Kadananoff, physicist and applied mathematician at the University of Chicago, finds the most engaging questions deal with the rise of complex systems. Kadanoff worries that particle physicists and cosmologists are missing an important trick if they only focus on the very small and the very large. "We still don't know how ordinary window glass works and keeps it shape," says Kadanoff. "The investigation of familiar things is just as important in the search for understanding." Life itself, he says, will only be truly understood by decoding how simple constituents with simple interactions can lead to complex phenomena.

What is reality really? The material world may, at some level, lie beyond comprehension, but Anton Zeilinger, professor of physics at the University of Vienna, is profoundly hopeful that physicists have merely scratched the surface of something much bigger. Zeilinger specialises in quantum experiments that demonstrate the apparent influence of observers in the shaping of reality. "Maybe the real breakthrough will come when we start to realise the connections between reality, knowledge and our actions," he says. The concept is mind-bending, but it is well established in practice. Zeilinger and others have shown that particles that are widely separated can somehow have quantum states that are linked, so that observing one affects the outcome of the other. No one has yet fathomed how the universe seems to know when it is being watched.
Seven questions that keep physicists up at night