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Renaissance men: Jaz (left) and Piers Coleman at the European premier of Music of the Quantum.

On almost every street corner in Prague, someone is handing out flyers for a concert in one of the city's historic churches. In one, it's a recital of Mozart; in another, Vivaldi. But on this balmy July evening, I join a crowd of physicists at the Bethlehem Chapel who have come to hear something less familiar: music by a contemporary composer, whose muse tonight is the science of quantum matter.

First, we are treated to a lecture by Tony Leggett of the University of Illinois at Urbana-Champaign, who shared the 2003 physics Nobel for his theories on the behaviour of superfluid helium-3. Then the overhead projector is removed to make way for two harps, a double bass, violin and accordion. A quintet of young Czech musicians takes to the stage. Against a painted backdrop of musical scores from the fifteenth century, melodies from the violin and accordion intertwine to create Music of the Quantum.

The concert is the brainchild of the brothers Coleman — one clad tonight in a short-sleeved shirt and tie, the other in a long black jacket over jeans and sandals. The sober-looking Piers is a theoretical physicist at Rutgers University in New Jersey. At 46, he is the elder by two years, but looks more boyish than his bohemian brother. Jeremy 'Jaz' Coleman is composer-in-residence with the Prague Symphony Orchestra. But to many fans, he is better known as leader of the experimental rock group Killing Joke, formed in 1979 from the embers of the British punk scene.

Music of the Quantum was commissioned by the Institute for Complex Adaptive Matter, a network of researchers that aims to advance condensed-matter science (see 'Small science thinks big', overleaf). It premiered in 2003 at Columbia University in New York, on the weekend that the United States invaded Iraq. This resulted in a disappointing attendance, as most New Yorkers remained glued to their TV sets.

The brothers are hoping for a more enthusiastic reception in the Czech capital, where the music was composed. Earlier in the day, in a wide-ranging discussion over lunch in Prague's old quarter, they talk about their motivations. "Whether it is science or art, the idea is to make the world a more beautiful place," says Jaz. For Piers, the ultimate goal is to communicate ideas about physics to a wider public. "Scientists have a duty to explain to those who are footing the bill what makes our hearts beat faster," he says.

The da Vinci road
The brothers' respective interests took them down separate paths from an early age. "This is the first time we've done anything together since we were kids," says Piers. They both recall a happy childhood in Cheltenham, UK, nurtured by an English father and a half-Bengali mother — both of them teachers — who encouraged the boys to aspire to Leonardo da Vinci's Renaissance thinking.

D. PARKER/IMI/A. HAVLICKOVA/CMD20 SECRETARIAT

Concerted effort: Tomas Damec (above) and Veronika Vachalova wrestle with physics.

For Jaz, school proved a less harmonious environment. He was bullied because of his mixed-race background, but reckons that these hard knocks have served him well. "My father always said it was good training for the music industry," he says. Jaz gave up on conventional schooling at 14, and three years later formed Killing Joke.

While Piers studied physics at the University of Cambridge and then at Princeton University in New Jersey, Jaz lived the stateless existence of a touring rock musician. Listening to Killing Joke has always been an intense experience — 'doom-laden' is a common description of their heavy, rhythmic sound — and Jaz soon acquired a reputation for eccentric behaviour. In 1982, he suddenly disappeared to Iceland, fearing an imminent apocalypse.

The conflagration never came, and over the subsequent years, Jaz has done his best to live up to his parents' Renaissance ideals. In 2003, Killing Joke released a critically acclaimed eleventh studio album. In parallel, Jaz has built a career as a classical composer. He delights in crossing boundaries, whether composing contemporary music for Maori singers and Czech folk groups or collaborating with Vanessa-Mae on a Disney film soundtrack. He has recorded with artists as diverse as Sarah Brightman and Mick Jagger, and is now working on his second opera.

Piers' career has been more conventional, even though he would love to be able to jump between scientific disciplines in the same way that Jaz leaps from one musical genre to another. "I'd like to think it is possible," Piers says — but concedes that the specialization required of today's scientists makes this an unlikely dream. In tutoring his students, however, Piers tries to encourage a broader outlook, telling them that "equations are like haiku", with their own poetic beauty.

For Piers, the collaboration with his brother represents an unusual opportunity to meld science and art. He first got Jaz interested in physics by sending him The Dancing Wu Li Masters, a 1979 book by Gary Zukav that sought to engage the public with theoretical physics by drawing parallels with Eastern philosophy.

The impossible dream
In keeping with this introduction, Jaz has a spiritual approach to science, and is drawn to outlandish ideas. He is fascinated, for instance, by anything to do with antigravity. "As you can see, we have great discussions," says Piers, laughing. He has told Jaz that antigravity cannot exist, but argues that what science can do — levitating a magnet above a superconductor, for instance, as he shows in a movie during the concert — is just as wonderful. "If you want to do great science, or great art, you need a dream of what is possible," Piers concludes.

Aside from a chance to collaborate with his brother, Jaz was attracted by the ambitious brief that Piers gave him. Each of the composition's three movements tries to embody different concepts: emergence and broken symmetry, phase transformation and criticality, and the duality of the quantum world.

Criticality is a tough concept to explain in words, let alone music. Physicists know that new forms of order can develop within matter through phase transformations, which drastically change the material's properties. Examples include the emergence of magnetism or superconductivity at certain temperatures. Matter that is close to such a transformation is said to be in a critical state, and Piers wanted the movement to convey its dynamic behaviour.

"I am forever trying to understand my brother and his work," says Jaz. "I'm a musician and composer, so I love numbers." But when it comes to theoretical physics, Jaz admits that Piers might as well be speaking Chinese. So they communicate in visual terms. For the final movement on quantum duality, Piers wanted a piece from which the listener can either hear two things at once, or by listening carefully just one or the other. So he urged Jaz to create the musical equivalent of an Escher drawing.

Given his own dual musical existence, Jaz may be the ideal composer to write about the quantum world. For him, the rock band is a collective, visceral experience, whereas the life of a classical composer is solitary and cerebral. Killing Joke is about getting "the anger and sickness out of me", he says. But when it comes to his classical compositions, Jaz is a romantic purist, stressing melody above all else.

Jaz also divides his time between contrasting environments. He spends half the year in Europe, immersed in the cultural intensity of Prague, retreating to a remote island off the coast of New Zealand for the remainder. There he is building a house of his own design, which will be powered by renewable energy.

Raising the bar
 

In writing Music of the Quantum, both Jaz and Piers wanted to engage non-physicists with the beauty of its underlying scientific concepts. "The idea of these concerts is to inspire, to make people think in different ways," says Jaz.

But the two performances can't claim to have achieved great outreach. Half of the audience in New York were scientists, the rest what Jaz calls "science groupies". And owing to restrictions surrounding the use of the venue, the Prague event is not open to the public. Instead, it has been organized as a cultural evening for those attending a meeting on condensed matter, hosted by the European Physical Society.

Piers is disappointed, but hopes that his example will inspire other condensed-matter physicists to reach out to a wider public. "It's a controversial issue," he says — some of his colleagues believe that the beauty of science should emerge naturally from the work, and doesn't need to be packaged for a wider audience. "How élitist," Jaz observes.

A. HAVLICKOVA/CMD20 SECRETARIAT

Take note: Piers Coleman discusses the physics concepts that inspired the music.

In the Bethlehem Chapel, Piers introduces each movement with a brief lecture on some of the physics concepts that inspired the work, leaving the audience with a final thought or image — a snowflake to represent broken symmetry, for instance.

Jaz is up next. He's a very physical conductor, often moving his whole body, whipping round his shoulder-length hair, with the music. "The three movements are essentially dances," he explains.

Music of the Quantum is uplifting, and the musicians are clearly talented. Piers' talks before each movement are refreshingly wide-ranging and entertaining. Some physicists might baulk at the reincarnation of Schrödinger's cat as the cartoon character Garfield, but Piers says that his 14-year-old son loved it.

Are the physical concepts successfully expressed within the harmony? I'm not entirely convinced, so I seek the views of scientists with a musical bent in the audience. Michelle Prevot, a chemist from the Max Plank Institute of Colloids and Interfaces in Potsdam, Germany, plays the clarinet and flute. She was impressed by the skill of the musicians and intrigued by the unconventional nature of the quintet — using the contrasting sounds of a violin and accordion to carry overlapping melodies. But Bedrich Velicky, a theorist at Charles University in Prague, and also an amateur musician, felt that the three movements failed to reflect the depth of the concepts involved.

Perhaps physicists are too close to the subject matter — the music was composed for a wider public, after all. And Piers hopes that this goal won't be lost forever. There are plans for a CD and a website, which will include sound and film clips from the concerts, along with interactive quantum experiments and soundbites from interviews conducted with audience members from the New York performance.

The website should be finished by early autumn, but that will depend on the brothers' other commitments. "In parallel with this, serious physics is going on in my life, and serious music is going on in Jaz's," he says.

For his part, Jaz seems happy to be kept busy. "There's no slowing down in our family," he says. It's about "hurtling to the grave, grinning as we go".