For the first time, researchers at the University of Waterloo's Institute for Quantum Computing (IQC) and the University of Innsbruck in Austria have performed a quantum simulation of a two-dimensional particle physics theory on a qudit quantum computer, bringing us closer to understanding nature at its most fundamental level.
By using a qudit quantum computer, scientists hope to understand fundamental mysteries about the nature of our universe - what happens inside a neutron star, or what states of matter are possible - with fewer errors than a qubit quantum computer and much faster.
IQC and University of Innsbruck researchers performed a quantum electrodynamic simulation including particles, antiparticles, and the electric and magnetic fields between them on a two-dimensional grid. Their paper, Simulating 2D lattice gauge theories on a qudit quantum computer, was published in Nature Physics earlier this week.
The research group at IQC was led by Dr. Christine Muschik, professor in the Department of Physics and Astronomy. They developed the qudit mathematical framework to run the physics simulation and the protocol that was used for the quantum computations.
Dr. Christine Muschik (Photo credit: Perimeter Institute).
Dr. Martin Ringbauer, professor at the University of Innsbruck, led the team that built the qudit quantum computer using Calcium ions.
"Quantum technology has so much promise and qudits play an important part because they make quantum computers much more resource efficient," Muschik says.
Most quantum computers use qubits to process information. Like classical bits, qubits are represented by zeros and ones, but they can also be in superposition states of zero and one. Qudits, on the other hand, can hold multiple states beyond just two. The qudits in this research encoded information in five different states.
Beyond deepening our understanding of the natural world, faster and more resource-efficient qudit quantum computers can speed up potential applications of quantum computations ranging from drug discovery to designing new materials.
Dr. Martin Ringbauer, professor at the University of Innsbruck.
"Qudits have the potential to greatly improve the resource efficiency of quantum computers and with that bring interesting applications closer within reach," Ringbauer says.
"This is the first complex qudit algorithm," Muschik says. "Before, several basic building blocks for a qudit quantum computer had been developed. In this work, we developed improved qudit gates, put all the parts together and took the results for a test drive around the block so to speak; and it drove well."
The standard model of particle physics explains the matter and forces that shape our world at the atomic level and describes particles and antiparticles interacting with electric and magnetic fields. But many important questions in modern physics still can't be answered, even with today's biggest supercomputers.
"Large problem classes within the standard model of particle physics are inaccessible to standard computational methods, and this is why science is fundamentally roadblocked to find out what nature can do. But programming a quantum computer can answer questions of modern science where we can't make inroads today," Muschik says. "A quantum computer can help us to understand what is allowed and possible within the standard model of particle physics."
But a common bottleneck with qubit quantum computers are long circuits and computations. Using qudits, IQC and University of Innsbruck researchers made the circuit ten times smaller than its qubit counterpart would be.
"Resource efficiency is key and qudits are a promising avenue for that," Ringbauer says.
