Data from one of Jeremy Levy’s experiments that measured electron spin in a magnetic field. The image shows the magnetic field (horizontal axis) as a function of time (vertical axis).  The blue and green colors represent the tumbling of the spin, which increases with the magnetic field.

“Beer is proof that God loves us and wants us to be happy,” wrote one of America’s great scientists, Benjamin Franklin. He would no doubt be pleased to see the marriage of beer and science taking place at Café Scientifique, a worldwide phenomenon that arrived in Pittsburgh this fall.

The next local Café Scientifique—7 p.m. Dec. 6at Penn Brewery on Pittsburgh’s North Side—will feature Pitt physics and astronomy professor Jeremy Levy leading a discussion of quantum computing, a technology so cutting-edge it doesn’t yet exist. (But Levy is working on that.)

The idea behind Café Scientifique is simply that science is worth discussing over a drink. Café Scientifique began in England in 1998, and cafés are now held all over the globe in coffeehouses and other locales—although “the best ones are all taking place in brew pubs,” says Tim Palucka, a writer in Carnegie Mellon University’s chemistry department. It was Palucka, together with local freelance science writer Leah Kaufman, who organized Pittsburgh’s Café Scientifique after reading about the movement in Science last year.

Attendance at the cafés has been steadily increasing, from around 50 attendees at first to more than 70 at the most recent talk. Topics have ranged from dark energy to genetically modified food. The event has gotten sponsorship from the Pittsburgh Technology Council and Alcoa.

Penn Brewery serves its own award-winning beer, made fresh on the premises, and hearty German food. The meetings usually begin with an informal half-hour talk, no PowerPoint presentations allowed—but Levy says he’s looking forward to that. “Actually, I sometimes fantasize about having my computer break down at the beginning of a talk, so I’m forced to discard all of the slides,” he jokes.

Levy plans to start his talk by trying to “convince the audience that the world really is quantum mechanical.”

“It’s a very strange subject,” he says. For example, the laws of quantum mechanics are reversible “if you change the direction of time” (which, though many people would be interested in turning back the clock, just doesn’t happen very often). And measuring anything about a quantum mechanical system changes it.

“When you tell people, it just sounds too weird; they just tune it out in some sense because they just don’t believe it,” Levy says. “But there’s no way around it—everything is quantum mechanical. We just don’t see it because we’re too big.”

The idea behind quantum computing is to use laws of quantum mechanics to make significantly faster computers. Although such “quantum computers” don’t yet exist, dozens of teams around the world, including Levy’s, are working on making them a reality. Levy doesn’t know how long it will take to build a functioning quantum computer, but he says, “I’d like to be able to hit the ‘On’ switch before I die.”

On a quantum computer, most programs wouldn’t run faster—a quantum screensaver wouldn’t run any faster than a normal screensaver, for example—but certain crucial applications would. “It’s something that could allow certain things to be calculated that would otherwise be basically impossible,” Levy says.

And that worries some people, particularly those at government security agencies. “The quantum computer really is a potentially disruptive technology,” notes Levy. “It’s actually quite scary for those people who like to guard their secrets.”

All of today’s Internet encryption schemes rely on the simple fact that it’s relatively easy to multiply two large prime numbers together, but very difficult to pull them apart. That difference allows two entities that have never before communicated with one another to send secure messages. Internet credit card transactions, for example, rely on this security measure.

Quantum computing is worrisome because a quantum computer could factor large prime numbers exponentially faster than ordinary computers can. “If these numbers are big enough, it can take longer than the age of the universe for ordinary computers to crack them,” says Levy. “But it would take a very reasonable amount of time for quantum computers.”

However, Levy believes that there could be an even more important use for quantum computers than decryption: solving the most important equation in quantum mechanics, the Schrödinger equation. Solving this equation efficiently would allow researchers to predict, for example, how chemical reactions or bonding would take place. “I believe that ultimately, once a quantum computer is built, those types of applications will probably overshadow the one that is causing a lot of people at these agencies to be all hot and bothered,” says Levy.

Quantum computers would work basically the same way all other computers do, relying on switches, or bits, that can be turned either “on” or “off.” In quantum computing, those bits would be based on the spin of the electron, which can be either “up” or “down” (or both at the same time—but don’t try to wrap your head around that one). To form quantum bits, Levy’s team lays carbon and germanium atoms onto a tiny slab of silicon and then adds another electron.

If this technology progressed to a working stage, it would literally represent a “quantum leap” in computing power. As Levy points out, “it’s not just the next generation of computers—it’s something totally different.”

After Levy’s talk, there will be a break (“so everybody can get more beer and order things,” says Palucka) followed by an hour or so of discussion.

Physicist Richard Feynman famously said, “Nobody understands quantum mechanics.” But after enough Penn Pilsner at next week’s Café Scientifique, attendees might either believe that they do, or won’t mind if they don’t.

Jeremy Levy will speak at Café Scientifique at 7 p.m. Dec. 6 in Penn Brewery, 800 Vinial St.,Pittsburgh. See www.cafescipgh.org for details and for more information on quantum computing. On May 2 at a time to be announced, Lisa Parker, a Pitt associate professor of human genetics and health services administration, will lead a Café Scientifique discussion on bioethics and genetics, also in Penn Brewery.