Quantum computer can simulate infinite row of chaotic particles

Using just a handful of quantum bits, researchers have used a quantum computer to simulate an infinite line of electron-like particles. The technique can be used to better understand the behavior of molecules in materials


Physics


August 4, 2022

Quantum bits made of charged ytterbium atoms, kept in a chamber of glass and metal

Quantum bits made of charged ytterbium atoms, kept in a chamber of glass and metal

quantum

A quantum computer made of charged atoms can use just a handful of quantum bits to simulate how an infinitely long and chaotic line of interacting particles behaves over time.

The behavior of special materials, such as superconductorsand molecules that undergo interesting chemical reactions are often too complex to simulate even on supercomputers. Researchers have long thought that quantum computers would be better at such tasks if they could build one big enough.

Eli Chertkovy at the quantum computer company Quantinuum in Colorado and his colleagues have now devised a simulation algorithm that gets around this size constraint, allowing a quantum computer to simulate an infinitely long chain of interacting electron-like particles with very few quantum bits (qubits).

The researchers used qubits made of charged ytterbium atoms. They programmed them to run the new algorithm, which simulates a chain of particles all interacting with each other. The team set up the interactions so that the proposed mathematical analyzes from the past would make the particles behave chaotically – a mathematical concept that means that very small changes to the original setup have a big impact later on.

Usually, the number of particles a quantum computer can simulate depends on the number of qubits it can use. Here, the researchers used only three to eleven qubits.

Chertkov says the Quantinum quantum computer could do this because the algorithm told him to keep “recycling” qubits during the computation. If the computer needed more qubits, it would pick one it had already used, reset it, and then use it again, all without interfering with other qubits involved in the ongoing calculation.

The researchers already knew from previous calculations how a line of particles should behave over time and that’s what they saw in their simulation, which suggests it works.

Miles Stoudenmire at the Flatiron Institute in New York says the next test for the new algorithm would be to simulate a system that conventional computers can’t handle, such as particles in 2D materials rather than just in a line. Understanding what electrons do in those materials over time, for example, could help develop more efficient electronic devices.

Kaden Hazzard at Rice University in Texas says the chaotic element makes the simulation more relevant to the real world. If you were to pick any random nature-inspired system, it would probably be chaotic, he says.

Reference: physics, DOI: 10.1038/s41567-022-01689-7

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