Can Quantum Computers Help US Learn About the Inside a Neutron Star?

Newswise — A new paper in Nature Communications could put scientists on the path to understanding one of the wildest, hottest, and most densely packed places in the universe: a neutron star.

Christine Muschik, a faculty member at the University of Waterloo Institute for Quantum Computing (IQC) and a research associate faculty member at Perimeter Institute is part of a US-Canadian research group using a quantum computer to build on a theory of quantum chromodynamics that describes how different varieties of quarks and gluons (the most fundamental bits of nature) interact in nuclei.

To really understand the behaviour of the quark-gluon plasma in extreme conditions like the beginning of the universe, or the inside of a neutron star, scientists need a map, a so-called “phase diagram” to describe the phase transitions in those conditions that are so extreme — so dense and complex — that classical computer simulations of the models will fail.

But even with a quantum computer, the challenges of modelling such high particle density environments are huge.

“This is one of the areas where our current computers completely fail and we are motivated to use quantum computers,” says Muschik. “This work could teach us something about nature and which states of matter were possible in the early universe, for example.”

The team developed a simplified one-dimensional phase diagram that could be a launch point for the future study of quantum chromodynamics in such extreme environments. They successfully tested this in a trapped ion quantum computer with the team in the US, laying the foundation to explore QCD phenomena on quantum platforms, and making quantum simulators more efficient.

They used the motion of the trapped ions as auxiliary qubits for a new type of ancillae register that helped to make the quantum computations much more efficient.

“This is advancing the whole area of quantum computing, now that we have this new type of ancillae register that we can use to our advantage,” Muschik says.

The Waterloo team includes Abhijit Chakraborty, IQC postdoctoral fellow; Yasar Atas, joint research associate at IQC and Perimeter, and Jinglei Zhang, research associate at IQC.