Alán Aspuru-Guzik is a professor of chemistry and chemical biology at Harvard University, where he applies quantum computing to chemical calculations and studies charge transfer in materials used for renewable energy. He founded the Harvard Clean Energy Project, the world’s largest distributed computing effort, to search for possible molecules for use in organic solar cells. Neil Savage recently spoke with Aspuru-Guzik about his love of computing and chemistry, as well as the role of open-access science in solving big problems.Alán Aspuru-Guzik, Harvard University
How did you end up mixing chemistry and computing?
When I was
in junior high school, I represented Mexico in the International Chemistry
Olympiad in Norway. That was very important because it made me realize
how much I loved science and chemistry. At the same time I was a computer
hacker, which was fun.So I’ve fulfilled my two goals
that I had when I was a kid: hacking computers and learning chemistry.
My group works at the interface of all these fields—chemistry, applied mathematics, computer science, and physics. It is at the interfaces
that we find the most interesting and most challenging research questions.
We take an idea from one field and apply it to the other and vice
versa, or grow new ideas from all these different fields.
Why apply quantum
computing to chemistry?
Ultimately, all matter obeys the
rules of quantum mechanics. If you want to find out, for example,
whether a molecule will work for a battery, work for solar cells,
or be a useful coating, you need to dig into the quantum mechanical
properties of that particular material. Classical types of studies
will not begin to even be able to address this question.The
problem is that solving quantum mechanical equations on a regular
computer is too hard. If you have a molecule large enough, even if
you have the largest supercomputer in the world, you cannot do it.If you had a device that followed the rules of quantum mechanics
for doing computations, you could in principle simulate matter exactly.
We’ve been developing programs for quantum computers and using
the early quantum simulators that are coming along to perform calculations
for small molecules. Quantum computing has been picking up, and it’s
not crazy to think that in the next few years, maybe in a decade,
we will have quantum computers that perform very nontrivial chemistry
calculations. Because a quantum computer can do exact calculations
efficiently, you’ll basically put the classical computers into
retirement.
While you’re waiting for quantum computers to mature,
what are you doing to tackle the same problems through the Harvard Clean Energy Project?
We’ve run approximate calculations
on donated computer time from many people around the world. We’re
talking about literally hundreds of millions of calculations done
over tens of thousands of years of computer time through the IBM World Community Grid. The idea is to find new molecules for organic solar
cells. These devices promise to be low-cost, useful applications for
developing countries where there is no electrical grid. You could
have these very nice, flexible solar cells that are easy to make and
easy to transport. We’ve ranked a list of about 75,000 molecules
that could be very good for making solar cells, and we’re working
with people around the world to actually start making the first molecules.Recently, we designed a molecule for the first organic batteries.
It was made in this accelerated process of computational design coupled
to experiment. It’s been one of our biggest successes recently.
The
project is open access, so that anybody can see the results of your
calculations. Why set it up that way?
One of my convictions
is that the more we open scientific data to the world, the bigger
impact it will have on society. It is important, I think, that if
people are donating the computer time for free that they get access
to their results so that humanity as a whole can benefit from it.
In the context of journals, open access is worth a lot to me because
it means that there are no pay walls for the papers. When I was an
undergraduate in Mexico, there were many journals that I didn’t
have access to or that were very hard to get. You had to make a request
for the university to purchase that particular article for you. These
things actually stop people from being able to do research as quickly
as possible. So I think that not only scientific data, but also scientific
publications, should be as available as possible.Ultimately,
our goal should be advancing scientific progress. Having journals
available to everybody in the world really maximizes
the impact of our science. I promised myself that I would publish
as much as possible in open-access journals, and in the last year
we’ve published seven.Neil Savage is a freelance contributor to Chemical & Engineering News, the weekly newsmagazine of the American Chemical Society.