PHYSICS is often a waiting game. Exploring the deepest foundations of reality is rarely straightforward. Take tests of relativity, for example. Gravity Probe B, which is due to deliver its initial results on relativity later this year, took 40 years to launch into space.
And LIGO, the Laser Interferometer Gravitational-Wave Observatory, begun in the early 1970s is only operational now. Even so it is unlikely to see any gravity waves, from the birth of a black hole for example, without an upgrade that is not due until 2010. In fact, we probably will not be certain about the existence of gravity waves until after a space-based gravitational wave detector called LISA launches in 2015.
By then, we might have clues from a different source about the kind of physics that will replace Einstein鈥檚 theory. The Large Hadron Collider (LHC) at CERN, the European centre for particle physics, near Geneva, will tell us more about the subatomic world, which will feed into theories of how general relativity can be united with quantum mechanics. The LHC should produce results in 2008, more than 20 years after it was proposed.
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Meanwhile, researchers in solid-state physics are starting to wonder if they might beat the big machines to the answers. Solid-state physics, which deals with the behaviour of structures such as metals and semiconductors, is in turmoil over 鈥渜uantum critical鈥� materials (鈥淭he quantum cocktail鈥�). In these crystals, the uncertainty principle produces strange behaviours that hold great promise.
For a start, many of these crystals display high-temperature superconductivity 鈥� a phenomenon that has defied explanation for decades. Now it seems that quantum criticality might do the trick. Even more exciting is speculation that these materials offer analogues for some of the most intriguing phenomena in physics, including black holes and the 鈥渦nification of forces鈥�, the idea that all forces, including gravity, arose from a single primeval force.
Physicists have long wanted to recreate the high energies of the big bang, and the LHC is designed to take us part way towards that goal. Quantum critical crystals may give us the means to probe something like the early universe in low-temperature physics labs.
Big Physics remains a necessary part of exploring reality. But it is heartening to see that not all approaches to answering the big questions need to be hugely expensive and time-consuming. Solid-state physics 鈥� the field that gave LIGO its lasers and the LHC its particle detectors 鈥� may yet hold its own in the race to understand how the universe works. If so, the wait for answers may not be nearly as long as we expected.
