Birds are migrating north, flowers are blooming, juniper pollen is making us sneeze. Spring is on its way — and we owe much of the season's vibrancy to what physicist Seth Lloyd likes to call "quantum mechanical hanky-panky."

Life, it turns out, has quite a lot to do with quantum mechanics, the area of physics first developed to understand what Albert Einstein and his contemporaries thought was some pretty strange behavior on the part of elementary particles like electrons. Since then, scientists have shown how quantum physics could, theoretically, lead to faster, more efficient and more secure computers — an area of study called quantum computing.

The fun part, Lloyd says, is that plants may have had a billion-year head start on actually building quantum computers.

Lloyd, a renowned Massachusetts Institute of Technology professor visiting Santa Fe as a Santa Fe Institute Miller Scholar, got interested in the quantum underpinnings of life in an unusual way. Back in 2007, the New York Times reported on a team of physicists who suggested that a particular microorganism called green sulphur bacteria acted like a quantum computer, and it was doing so to make photosynthesis — the process plants use to convert light energy into chemical energy — more efficient.

Initially, Lloyd and his colleagues, all experts in quantum computing, didn't take it seriously. "We thought this was really funny, (but) I got designated to look into it," he says.

While some of the details in the article were off, it turned out that green sulphur bacteria really were doing quantum computations. That discovery eventually led Lloyd to organize a series of small workshops at the Santa Fe Institute earlier this year on the relatively new field of quantum biology, which aims to understand how living things use quantum processes to become more efficient, more sensitive and generally better than classical physics and chemistry seem to allow.

It shouldn't come as a surprise that quantum physics lies at the foundation of life. After all, the fundamental processes of living things go on at the level of atoms and molecules — the level quantum mechanics was designed to understand. Still, physicists and others had thought biological processes lay in the so-called "semi-classical" domain, where quantum physics matters, but many of its finer details can be ignored.

For something like photosynthesis, however, semiclassical physics only gets you so far. Biologists and physicists had this much right: When plants absorb energy from the sun's rays, that energy gets passed among molecules called chromophores until it reaches a place called a reaction center, where the light energy is converted into chemical energy.

Less clear was how, given the many paths the energy might take through the chromophores, plants could photosynthesize efficiently enough to stay alive. What Lloyd and others figured out is that plants make it happen using a phenomenon called quantum coherence, which means the energy can take all those paths at once and use information from each path to find the reaction center very quickly.

When Lloyd and other physicists looked beyond photosynthesis, they found other, more surprising places where quantum biology seems to be taking place.

New research on our highly discriminating sense of smell, for example, suggests that a molecule's quantum mechanical vibrations determine its odor — molecules with different shapes but that vibrate the same way smell the same, and molecules with the same shapes but different vibrations smell different.

Weirder still, birds might be using quantum mechanics when they migrate north and south. Scientists know that birds can tell when they're flying in line with Earth's magnetic field, but how they can tell remains a mystery.

Recent experiments suggest birds can detect changes to the spin of an electron — sort of like the spin of a tether ball — as its gets pushed around by a magnetic field. Birds, it seems, might be using a deeply quantum property of the tiny particles within their molecules as a built-in compass.

The results are exciting, though Lloyd says he isn't sure where the field is headed.

"One possibility is there's loads of quantum hanky-panky going on in these living systems that's just waiting to be discovered," or quantum biology might comprise photosynthesis and a few other things. Likewise, the field might give us new insight into the origin of life — or it might only reveal some of nature's more impressive feats of engineering.

Either way, the work that's been done so far is revealing. Looking out over Santa Fe and the surrounding landscape one recent afternoon from the Santa Fe Institute, Lloyd points out that photosynthesis — and quantum physics — is responsible for every plant we see and thus pretty much all life on Earth.

"The unphotosynthetic life," Lloyd says in his characteristically sly way, "is not worth living."

Nathan Collins is an Omidyar Fellow at the Santa Fe Institute and holds graduate degrees in physics and political science. He is studying how voters' choices change over time as well as topics in evolutionary biology. When not researching weighty scientific matters, Collins is a science writer for publications such as New Scientist and Scientific American Mind.

ABOUT THE SERIES

• The Santa Fe Institute is a private, not-for-profit, independent research and education center founded in 1984. At the Santa Fe Institute, more than 150 top researchers from around the world gather to study and understand the theoretical foundations and patterns underlying the complex systems that are most critical to society — economies, ecosystems, conflict, disease human social institutions, and the global condition. By freely synthesizing ideas from many fields, they are pursuing creative insights to improve our world. 

This column is the fourth in a series by researchers at the Santa Fe Institute to be published in The New Mexican.