One of the prime applications for quantum computers is to simulate natural quantum phenomena, and in a newly published study, researchers from Canada’s D-Wave Systems have demonstrated how to do it.
The phenomenon that they simulated involves a topological phase transition associated with thin-film superconductivity and superfluidity. It’s called the Kosterlitz-Thouless phase transition, and figuring out how the transition could be done earned Brown University’s Michael Kosterlitz and the University of Washington’s David Thouless shares of the 2016 Nobel Prize in physics.
Today Kosterlitz hailed the quantum computer simulation, which is described in a paper published by Nature.
“This paper represents a breakthrough in the simulation of physical systems which are otherwise essentially impossible,” Kosterlitz said in a D-Wave news release. “The test reproduces most of the expected results, which is a remarkable achievement.”
D-Wave’s chief scientist, Mohammad Amin, said the feat represents “a landmark in the field of quantum computation.”
“For the first time, a theoretically predicted state of matter was realized in quantum simulation before being demonstrated in a real magnetic material,” Amin said. “This is a significant step toward reaching the goal of quantum simulation, enabling the study of material properties before making them in the lab, a process that today can be very costly and time-consuming.”
The Kosterlitz-Thouless phase transition has been modeled previously, using more conventional simulation methods. D-Wave — which is headquartered in Burnaby, a suburb of Vancouver, B.C. — achieved results that were consistent with those classical simulations, using its fully programmable, 2,048-qubit annealing quantum computer.
D-Wave’s 2000Q computer makes use of superconducting quantum interference device flux qubits, or SQUIDs, fabricated as an integrated circuit. Unlike classical bits, which represent a definite value of either one or zero, qubits can represent both values simultaneously in the course of a calculation.
Over the years, researchers have debated whether D-Wave’s computers truly exhibit quantum effects. The newly published research, added to a different type of simulation that D-Wave described in a paper published last month by Science, firms up D-Wave’s quantum pedigree.
Richard Feynman, a pioneer in the field of quantum physics, first proposed the idea of using quantum computers to simulate quantum phenomena back in 1982.
“The ability to demonstrate two very different quantum simulations … illustrates the programmability and flexibility of D-Wave’s quantum computer,” said D-Wave’s Andrew King, the Nature study’s principal author. “This programmability and flexibility were two key ingredients in Richard Feynman’s original vision of a quantum simulator.”
If quantum computers work the way researchers expect, the behavior of custom-designed superconductors and other exotic materials could be predicted — and tweaked as necessary — well in advance of fabrication.
“This gives hope that future quantum simulators will be able to explore more complex and poorly understood systems, so that one can trust the simulation results in quantitative detail as a model of a physical system,” Kosterlitz said. “I look forward to seeing future applications of this simulation method.”
D-Wave Systems has attracted total funding of more than $200 million from a bevy of high-profile investors, including Amazon founder Jeff Bezos’ venture capital fund, Goldman Sachs and In-Q-Tel. Lockheed Martin, Google, NASA, Los Alamos National Laboratory and Oak Ridge National Laboratory number among D-Wave’s customers.
King and Amin are among 29 authors of the Nature paper, titled “Observation of Topological Phenomena in a Programmable Lattice of 1,800 Qubits.” All are from D-Wave Systems, except for Juan Carrasquilla of the Vector Institute.