How much do we really know about the objects around us? We know that everyday materials (like the ceramic in your coffee cup) are made of billions of tiny particles. Scientists who study materials usually investigate their properties by describing them as composite systems in terms of their basic particles.
“New exciting phenomena are expected in systems made of particles that interact with each other so strongly that the emergent behavior of the material cannot be understood in terms of independent constituent entities,” says Adolfo del Campo, associate professor of physics at UMass Boston.
In other words, there are types of materials that are so complex that scientists can’t just divide up the problem into a bunch of individual systems. A technologically relevant example is that of certain superconductors, through which an electrical current can flow without resistance. To understand them, physicists need new tools that can account for the description of the material as a whole. “Holographic” superconductors are one type of material that needs this kind of novel approach.
Adolfo del Campo studies the behavior of systems made of strongly-interacting particles. In a new paper published in the journal Nature Communications, he collaborated with Julian Sonner of MIT and Wojciech Zurek of Los Alamos National Laboratory to look at what happens when a superconductor is heated up, and then cooled down at different rates.
“We can show, using so-called holographic models, that the dynamics of these superconducting materials is universal,” says del Campo.
Knowing that they can make universal statements about how the dynamics of these superconductors gives scientists a new way to understand those materials that are made up of strongly correlated systems.
In order to describe this discovery in formulae, the scientists used Einstein’s theory of general relativity, which is normally used in astrophysics and cosmology. One of the most unexpected results at the cutting-edge of physics, known as “holographic mapping”, or more technically, “gauge/gravity duality” is that there is a connection between Einstein’s famous theory and the behavior of materials with strong interactions.
According to del Campo, working with Sonner and Zurek was one of the best aspects of this project. “It’s like playing with the Rolling Stones,” he says of his colleagues.
When asked why he decided to study this particular branch of physics, del Campo says that he might as well answer why he likes a certain piece of music or a piece of art.
“Believe me, there’s a lot of beauty . . . It’s creative. There’s lots of creativity in physics. You might say it’s a bit hidden because we use jargon,” he says.
He compares it to another subject he’s passionate about, classical music: “There are pieces that I could not understand at the beginning. The first time I listened to them, I said ‘too crazy for me.’”
But, over time, he came to appreciate the history and theory behind these complex pieces.
“In physics, it’s like that – you develop a taste. There’s a mathematical beauty . . . you appreciate the reasoning of other people. You marvel at how you can predict things, and you can say something about nature,” he says.