Ignacio Cirac

Director of the Theory Division, Max Planck Institute for Quantum Optics (Germany)

Ignacio Cirac (Manresa, Spain; 1965) earned his PhD in Physics in 1991 from the Universidad Complutense de Madrid. From then until 1996, he was an associate professor in the Department of Applied Physics at the University of Castilla-La Mancha. After a postdoctoral stay (1993-1994) with Peter Zoller at the Joint Institute for Laboratory Astrophysics of the University of Colorado (United States), he moved to the University of Innsbruck (Austria) to take up a professorship in the Institute of Theoretical Physics (1996-2001).

Since 2001, he has led the Theory Division at the Max Planck Institute for Quantum Optics in Garching, Germany. He is an honorary professor at the Technical University of Munich (TUM), and a Distinguished Visiting Professor and Research Advisor at the Institute of Photonic Sciences (ICFO) in Barcelona. He has been a member of research teams at Massachusetts Institute of Technology and the universities of Harvard, Hamburg, Hannover, Bristol and Paris, among others.

After winning the BBVA Foundation Frontiers of Knowledge Award jointly with Peter Zoller, both men went on to receive the Wolf Prize in Physics (2013), considered the second most important after the Nobel Prize, and the Benjamin Franklin Medal of the Franklin Institute (2010, along with David Wineland). Cirac also holds the Quantum Electronics Prize of the European Science Foundation (2005) and the Niels Bohr Institute Medal of Honor (2013), and is a member of the American Physical Society and the Spanish and Austrian Academies of Science. In Spain, he has been granted the Medal of the Royal Physical Society of Spain (2002), the National Blas Cabrera Prize for Physical, Material and Earth Sciences (2007) and the Grand Cross of the Order of the Second of May (2011).

“We are entering a new world, a microscopic world which we are learning to manipulate and control, and where we are encountering new laws of nature”. This could be the opening of a science fiction film. But no. The words belong to physicist Ignacio Cirac and refer to the research being done in the world of the infinitesimal, at the atomic and molecular scale. In the realm of quantum mechanics.

The last great revolution in physics began around a century ago and posed a huge challenge to human intuition and creativity. Could anyone have predicted that the same thing could be in two places at once? Or that two objects far apart and physically unconnected could interact so closely that a change in one is instantly mirrored in the other? Confronted with phenomena that contradict the version of the world we receive through our senses, our first reaction is inevitably disbelief. And yet that is how things are. The laws that govern the quantum universe often clash with our common-sense view of reality, but are nonetheless strictly observed in nature. Today’s physicists have a wealth of evidence to prove that quantum mechanics is hard fact, and are now learning to exploit its possibilities.

Peter Zoller (Austria, 1952) and Ignacio Cirac are past masters at this particular art. And their work together could open the door to the quantum computer of the future; a revolutionary machine able to process data on a scale undreamt of in the past. A computer that runs using quantum mechanics could for instance, crack open the codes encrypting information, improve the accuracy of the mathematical simulations used for everything from predicting climate change to designing new materials, and, in all likelihood, crunch its way through some of the problems that today’s scientists find irresolvable, like deducing the three-dimensional structure of a protein based on its sequence of amino acids.

Zoller and Cirac’s collaboration dates back to the beginning of the 1990s. At the time, scientists were already speculating about building a quantum computer, but no one was sure if it could actually be done. Cirac was investigating the physical properties of ions – electrically charged atoms – and realized that some of these properties might hold the key to the long-sought machine. And what he then discovered, together with Peter Zoller, produced not one but two strides forward: not only was the quantum computer a real possibility – no fundamental laws ruled it out – but there was also a way to build one. The two scientists based their conjectures on what are known as “ion traps”, in which electrically charged and cooled atoms are trapped by an electric field and manipulated with lasers. The captive ions would then act as q-bits, the basic data units of quantum computing.

This research was written up in a joint paper published in 1995 by the prestigious journal Physical Review Letters: “Quantum Computation with Cold Trapped Ions,” which has since become one of the most widely cited articles in atomic physics and quantum optics. Shortly after it appeared, a series of laboratories worldwide began to experiment successfully with Zoller and Cirac’s ideas. In fact some small-scale prototypes have already been built based on the ion trap idea, and this technique still holds out the best promise for quantum computation.

But Zoller and Cirac’s collaboration did not end there. Both men have embarked on the study of a new state of matter called the “Bose-Einstein condensate,” in which atoms cooled to the lowest temperatures ever achieved – a billionth of a degree above absolute zero or -273 degrees Centigrade – oscillate in unison and coalesce into a single wave. Here too, Zoller and Cirac have produced visionary and ground-breaking work, which has not only built new bridges between quantum optics and solid state physics, but has also, crucially, paved the way for later discoveries.

The society that stands to benefit from all this research is avid for results. And a question both scientists are frequently asked is: when will we see a fully operating quantum computer? Peter Zoller has a short answer ready: “That is certainly the goal, though we still have a long way to go”. But the longer answer looks to the means and not just the ends. Ignacio Cirac, in particular, foresees a future rich in new developments. “We must remember that the road to quantum computation is paved with exciting phenomena which we can analyze using the physics we have today, and which will produce even more surprising results. That is always the way with basic research; you never know what you are going to discover. All we know is that we are entering a new world and what we do find is going to be important”.

Peter Zoller is full professor at the University of Innsbruck and, since 2003, scientific director at the Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences. Ignacio Cirac has headed the Theory Division at the Max Planck Institute for Quantum Optics in Garching, Germany, since 2001. Each has pursued his own separate research in the last decade, though finding time for occasional collaborations. Both men have over two hundred articles to their names in leading journals, but what colleagues single out is something unrecorded on their resumes: their enormous creativity.