The researchers were able to use half the usual quantum processing power to perform a detailed simulation using tangle forging.
IBM researchers have found a way to double the size of quantum simulations while using half the qubits on a quantum computer, through a process called tangle forging.
The tech company’s researchers said the technique can solve bigger problems on a quantum processor than before – enabling larger circuits on smaller hardware.
In a paper recently published in the journal PRX Quantum, the team succeeded in creating an accurate simulation of the ground state energy of a water molecule, representing 10 spin orbitals across five qubits of a CPU IBM quantum.
In an accompanying blog post, the IBM team said the tangle-forging technique takes a circuit operating on 2N qubits and separates that circuit into two N-qubit halves.
Usually, if researchers wanted to simulate 10 spin orbitals of a water molecule, they would need to use at least 10 qubits, since most quantum simulation techniques require one qubit for each relevant “feature” of the systems they are simulating. .
With tangle forging, the IBM researchers were able to split the problem in two, separating the 10 spin orbitals into two groups of five, then processing each group using only five qubits.
The team said entanglement forging is scalable and has wide application in a variety of problem structures, meaning it could extend the computing power of quantum systems.
“We have demonstrated a method that in many cases will allow you to run larger problems on your quantum processor than you otherwise could,” said Andrew Eddins, lead author of the paper.
“Entanglement forging provides an efficient method of using classical computational resources on quantum problems in a way that, in some ways, doubles your capacity. This effectively increases your qubit count by a factor of two, which is truly remarkable.
Paper co-author Sarah Sheldon said tangle forging represents an important addition to a family of quantum computing techniques known as “circuit knitting”.
“Other groups have worked on similar ideas of breaking circuits into smaller pieces, either by qubits or over time – like breaking gates – to solve larger problems. Tangle forging is a particularly scalable, at least for weak entanglement problems that have this amenable structure,” Sheldon said.
As IBM’s quantum computers are rolled out around the world, the tech company has been hard at work proving what these machines can do.
In a research paper last July, its researchers showed that quantum machine learning was able to discern patterns where classical computers missed the signal in the noise.
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