A Quantum Game Changer

Imagine a game of checkers, but instead of wooden pieces, lasers precisely maneuver ions across a minuscule grid. This concept, explored in a recent study published in Physical Review Letters, showcases a novel quantum “game” designed by theoretical physicists in colorado. This game can be played on a real quantum computer,a device that manipulates atoms to perform calculations.

Researchers tested their game on the Quantinuum System Model H1 Quantum Computer, developed by Quantinuum. This collaboration between the University of Colorado Boulder and Quantinuum highlights the potential of these devices.

According to study co-author Rahul Nandkishore, associate professor in the Department of physics at CU Boulder, the findings offer a glimpse into the capabilities of these devices. Small-scale quantum devices are rapidly coming online, said nandkishore. That really prompts the question: ‘What are they good for?’

The Quantum Advantage

Quantum computers hold the promise of revolutionizing various fields. Scientists believe they could one day perform tasks at speeds currently unimaginable,such as discovering new drugs or exploring atomic interactions.

Unlike conventional computers that use bits (switches representing zero or one), quantum computers rely on qubits. Qubits, made from atoms or other small objects, can represent zero, one, or both simultaneously, thanks to quantum physics.

However, controlling qubits is notoriously challenging. Study co-author David Stephen, a physicist at Quantinuum, explains that the research team assembled a network of qubits into a “topological” phase of matter, akin to a clump of tiny knots. This arrangement allowed them to play a mathematical game without disrupting the quantum computer.

In principle,there was nothing too surprising about this experiment. It worked exactly as we thought it would, in theory, Stephen said. But the fact that it did work so well can be seen as a benchmark for this quantum computer.

Quantum Pseudotelepathy

Quantum games, mathematical exercises that explore the possibilities of quantum physics, predate the frist quantum computer. Physicist David Mermin popularized the concept in 1990.

In a typical quantum game, players in separate rooms receive prompts and fill a grid with zeros and ones, aiming to complete a mathematical pattern. The catch? They can’t communicate during the game.

They can agree on whatever strategy they want in advance, but they can’t communicate during the game, said study co-author Oliver Hart, a postdoctoral associate in physics at CU Boulder. It’s relatively straightforward to show that there’s no strategy that wins the game with certainty.

Quantum physics offers a solution. Mermin proposed using entangled particles, where measuring one particle instantly affects the other, even when separated. Players can use these correlations to coordinate their answers, a phenomenon nicknamed quantum “pseudotelepathy.”

However, entangling particles in a quantum computer is challenging. Even slight disturbances can break the link between particles,and these errors accumulate as more qubits are added.

Tying Qubits in Knots

Nandkishore and his colleagues sought a more practical approach to quantum games.They utilized quantinuum’s System Model H1, a device with a chip that fits in the palm of your hand. This system uses lasers to control up to 20 ytterbium ions, which serve as qubits.

The researchers arranged the ytterbium ions into a two-dimensional grid, creating a unique quantum structure. Rather of simple entanglement between a few ions, the entire collection exhibited a “topological” order, as if the qubits were tied into knots.

We have order that’s associated with this global pattern of entanglement across the whole system, Nandkishore said. If you make a local disturbance, it shouldn’t mess it up.

The researchers,acting as quantum game players,made measurements of qubits inside H1-1. They achieved quantum pseudotelepathy, winning the game roughly 95% of the time, even with external disturbances and additional players.

While the team’s game may not solve real-world problems instantly, it demonstrates that today’s quantum computers can grow larger without losing their edge, at least in certain scenarios.

this study is proof of principle that there is something that quantum devices can already do that outperforms the best available classical strategy, and in a way that’s robust and scalable, he said.

FAQ: Quantum Computing

• What is a qubit? A qubit is the basic unit of facts in a quantum computer, capable of representing 0, 1, or both simultaneously.
• what are quantum computers good for? They are potentially useful for complex calculations like drug discovery,materials science,and cryptography.
• Are quantum computers replacing regular computers? No, they are designed for specific tasks that classical computers struggle with.
• What is quantum entanglement? It’s a phenomenon where two particles are linked, and measuring one instantly affects the other, even when separated.