# Iman Marvian: The “Magical Power” of Quantum Systems

*Tuesday, November 21, 2017*

**Iman Marvian**, a quantum information theorist, will be joining the Duke faculty in January 2018, with a joint appointment in physics and electrical and computer engineering. He’ll be adding to the efforts of others in physics and engineering who are working to design and build quantum computers. But Marvian has a broader vision. “The field is not just about building quantum computers,” he says. “That’s a big part, but not the only part.”

**Harold Baranger**, professor of physics, says, “Iman brings a very new perspective. He is the first theorist at Duke whose main central research program is in quantum information.”

In quantum computing, information is encoded in quantum states, which can represent more than the binary one or zero of classical computing. By taking advantage of quantum states and quantum behavior, these new computers have the potential to solve problems beyond the capabilities of today’s supercomputers. So far, only very small demonstration quantum computers have been built, but the field is progressing quickly. IBM recently unveiled a demonstration quantum computer made of 50 quantum bits, or qubits.

Other applications of quantum information theory include secure communications (quantum cryptography) and ultraprecise measurements of time and distance (quantum metrology). The latter was used in the LIGO experiment that documented Einstein’s gravitational waves in 2015.

At Duke, Marvian would like to expand his collaboration with experimentalists, and to help provide theory to support the development of quantum computers, quantum cryptography, and quantum metrology. He enjoys the iterative process of collaborative projects, particularly the continual refinement of theory based on input from experiments or numerical simulations. When Marvian visited Duke, it struck him as a place that fosters such collaboration.

Baranger says, “Quantum information is an interdisciplinary topic which involves physics and computer engineering and computer science. Iman is really an excellent researcher and an exciting fit for us in terms of making contacts with all three of those communities.”

One of Marvian’s interests is error correction, which is a set of theories and methods devised to protect quantum computers from errors introduced by noise in the environment. The field was pioneered in the mid-1990s by **Robert Calderbank** among others, who is now the Charles S. Sydnor Professor of Computer Science at Duke.

“The quantum system is very fragile,” Marvian says. “When it interacts with the environment, it can start acting like a classical system and the magical power of a quantum system is lost.” Error correction preserves the “magical power” even in the presence of noise.

In addition to making quantum computers possible, error correction turns out to be relevant in other areas of physics as well. “It was originally developed for answering this very practical question, ‘Is quantum computing still possible in the presence of noise or not?’” Marvian says. “Later people realized it has other implications.” For example, theorists working on quantum gravity have begun incorporating ideas from quantum error correction into their work.

Aside from computers and other applications, quantum information theory can also be used to flesh out theories in other areas of physics, including quantum mechanics, thermodynamics, and condensed matter systems.

Marvian is interested in using quantum information theory to illuminate quantum mechanics itself. “Quantum mechanics is not just a theory, it’s a framework for physical theories,” he says. “All of our physical theories are built on this framework, but we don’t understand quantum mechanics very well yet. In my opinion, quantum information theory gives us a lot of interesting tools to understand the foundations of quantum mechanics better.”

He also wants to use tools from quantum information theory to more fully develop some very old theories, including thermodynamics, and some newer ones, such as the branch of condensed matter theory involving a zero-temperature phase of matter called topological order.

Marvian, originally from Iran, is coming to Duke from a postdoctoral position at MIT. He enjoys listening to different kinds of music, from classical to jazz and blues, and is looking forward to attending shows at DPAC. “Durham is not a big city but it gives you a lot that you don’t expect from a city this size,” he says.

He also enjoys hiking and being in nature. Walking helps him relax and generate new ideas. “A lot of the time I just walk around and think about the questions I’m working on,” he says. “Of course at the end, you have to sit down and do some math.”

*Mary-Russell Roberson is a freelance science writer who lives in Durham.*

See Duke Electrical and Computer Engineering (ECE)'s new faculty profile on Prof. Marvian here. He was also featured in the *DukeToday* story "A Quantitative Investment in Promoting the Sciences at Duke." Read it here.