Dancing to invisible choreography, quantum computers can balance the noise
Large-scale quantum computers are waiting in the wings. One of the main reasons we don't have them yet is because quantum hardware is so noisy.
This isn’t the type of noise you’d want to shush in a crowded theater. When it comes to computers, noise means errors that crop up when conditions aren’t perfect.
“We need to find a way to detect errors and correct for them,” said graduate student Evangelos Piliouras. Working with physicist Ed Barnes, Piliouras devised a method to reduce the noise and make quantum computers more noise tolerant. His work was published last month in Nature Partner Journal Quantum Information.
Noise can have real-world implications even in a traditional computer, which uses a stream of electrical signals called bits that represent the 1s and 0s that make up binary code. Noise can knock a 0 into a 1, and a credit card transaction, for instance, might fail.
A quantum computer uses qubits, which are typically subatomic particles such as electrons or photons that can represent many possible combinations of 1 and 0 at the same time.
Occupying multiple states at once is called superposition and gives quantum computers tremendous power. But it’s a precarious move to hold.
Researchers get a qubit into superposition using electromagnetic pulses, like a precision laser or microwave beam. Once it's in superposition, even a little bit of noise — a slight vibration or temperature change — can cause a qubit to stumble out of superposition like a beginner ballerina.
To keep qubits on point, researchers do their best to protect them from the outside world in supercooled fridges and vacuum chambers. They’ve experimented with new materials and equipment to minimize noise, but there’s only so much that can be done to improve the hardware.
So they found another way: Over the past few decades, physicists discovered that they could lower error rates by tailoring the shape of those electromagnetic pulses that put the qubits into superposition.
This technique is called quantum control, and it’s endlessly configurable. The duration, frequency, and intensity of the pulses can be adjusted to change the qubit’s state and perform different operations.
“The blessing and the curse of quantum control is that you have infinitely many ways to achieve the same task, but nobody tells you the best way,” Piliouras said.
For many years, researchers believed that there was an inherent trade-off in quantum control: You can design the perfect pulse for a certain quantum operation, but the noise would be through the roof.
This is where Barnes, Piliouras, and their team come in: Their solution is built on a framework that describes the shape of the pulse as something cast by a hidden geometrical structure — as if it were a shadow of a 3D object on a wall. In the field of quantum physics, this perspective is referred to as quantum geometry.
The curves and corners of the invisible shape can dictate the parameters of the pulse, like a dancer’s choreography. The Virginia Tech researchers realized that they could simply adjust the shape of a 3D space curve to design a pulse that suppressed noise errors.
“We’ve been surprised multiple times by how simple and elegant the requirements for noise suppression become once we translate them into this geometric language,” Barnes said.
After honing their technique, Barnes and Piliouras teamed up with Hisham Amer, another Virginia Tech graduate student, who was able to verify it by running experiments on IBM’s quantum computing hardware.
With these performance improvements, we are one day closer to a large-scale quantum computing premiere.
Original study DOI 10.1038/s41534-026-01190-6
END
This isn’t the type of noise you’d want to shush in a crowded theater. When it comes to computers, noise means errors that crop up when conditions aren’t perfect.
“We need to find a way to detect errors and correct for them,” said graduate student Evangelos Piliouras. Working with physicist Ed Barnes, Piliouras devised a method to reduce the noise and make quantum computers more noise tolerant. His work was published last month in Nature Partner Journal Quantum Information.
Noise can have real-world implications even in a traditional computer, which uses a stream of electrical signals called bits that represent the 1s and 0s that make up binary code. Noise can knock a 0 into a 1, and a credit card transaction, for instance, might fail.
A quantum computer uses qubits, which are typically subatomic particles such as electrons or photons that can represent many possible combinations of 1 and 0 at the same time.
Occupying multiple states at once is called superposition and gives quantum computers tremendous power. But it’s a precarious move to hold.
Researchers get a qubit into superposition using electromagnetic pulses, like a precision laser or microwave beam. Once it's in superposition, even a little bit of noise — a slight vibration or temperature change — can cause a qubit to stumble out of superposition like a beginner ballerina.
To keep qubits on point, researchers do their best to protect them from the outside world in supercooled fridges and vacuum chambers. They’ve experimented with new materials and equipment to minimize noise, but there’s only so much that can be done to improve the hardware.
So they found another way: Over the past few decades, physicists discovered that they could lower error rates by tailoring the shape of those electromagnetic pulses that put the qubits into superposition.
This technique is called quantum control, and it’s endlessly configurable. The duration, frequency, and intensity of the pulses can be adjusted to change the qubit’s state and perform different operations.
“The blessing and the curse of quantum control is that you have infinitely many ways to achieve the same task, but nobody tells you the best way,” Piliouras said.
For many years, researchers believed that there was an inherent trade-off in quantum control: You can design the perfect pulse for a certain quantum operation, but the noise would be through the roof.
This is where Barnes, Piliouras, and their team come in: Their solution is built on a framework that describes the shape of the pulse as something cast by a hidden geometrical structure — as if it were a shadow of a 3D object on a wall. In the field of quantum physics, this perspective is referred to as quantum geometry.
The curves and corners of the invisible shape can dictate the parameters of the pulse, like a dancer’s choreography. The Virginia Tech researchers realized that they could simply adjust the shape of a 3D space curve to design a pulse that suppressed noise errors.
“We’ve been surprised multiple times by how simple and elegant the requirements for noise suppression become once we translate them into this geometric language,” Barnes said.
After honing their technique, Barnes and Piliouras teamed up with Hisham Amer, another Virginia Tech graduate student, who was able to verify it by running experiments on IBM’s quantum computing hardware.
With these performance improvements, we are one day closer to a large-scale quantum computing premiere.
Original study DOI 10.1038/s41534-026-01190-6
END