Last Updated on July 29, 2026 by Staff
Quantum computers are going to change the way we do computing by solving problems that’re too hard for the computers we use today. These quantum computers do not use the binary bits like our regular computers. Instead they use something called bits or qubits. These qubits can be in states at the same time, which is really unique.
This special ability of qubits can help scientists do a lot of things. They can use qubits to simulate materials, make complicated systems work better and solve problems in fields like medicine, artificial intelligence and physics.
There is a big problem with quantum computing. It is hard to measure the state of a qubit. Before a quantum computer can give us results we need to know if a qubit is in a state that means zero or one.
A team of researchers led by Pasquale Scarlino at EPFL has found a way to measure qubits faster and more accurately. They published their findings in PRX Quantum. Introduced a simpler way to do things that could make quantum computers work better.
Measurement Problem
One way to build a computer is to use superconducting circuits. These circuits are special because they can carry electricity without losing any energy. Only when they are very very cold. In these systems we measure qubits using something called microwave resonators. These resonators act like sensors that tell us what state a qubit is in.
However the old way of doing things has a limitation. The qubit and the microwave resonator are connected by a capacitor. This connection lets us detect the state of the qubit. It also makes the qubit and the resonator interact with each other.
This interaction is what allows us to measure the qubit. It can also disturb the qubit and make it lose its information or change its state. This is a problem because quantum computers need qubits to stay in their states for as long as possible.
New Design
To solve this problem the researchers at EPFL came up with a way to connect the qubit and the microwave resonator. By just using a capacitor they added something called a Josephson junction.
A Josephson junction is a component that lets electricity flow through a barrier. This creates an element that is very useful.
In the design the Josephson junction changes how the qubit and the resonator interact. This helps protect the qubit from losing its information during measurement. As a result we can use signals to detect the state of the qubit without disturbing it.
This new approach makes it easier to tell the difference between states of the qubit, which makes measurements faster and more accurate.
Strong Results
The researchers tested their design using transmon qubits which are a type of qubit that is less sensitive to noise. The results were very good. The system correctly identified the state of the qubit 99.4% of the time. It only took 68 nanoseconds to do the measurement.
The researchers also found that the measurement process did not change the state of the qubit 98.4% of the time. This is important because usually measuring a qubit can change its state.
The results matched what the researchers had predicted, which shows that the new design works as expected.
Future Impact
The new system is not better at measuring qubits but it is also simpler. Today’s quantum computers often need components like Purcell filters and special amplifiers to improve measurements. These extra components make the hardware more complicated and harder to build.
The new design does not need these components, which makes it easier to build and maintain. It also works well with readout which is a way to measure many qubits at the same time using the same hardware.
Researchers think that this new approach could be very useful for quantum computers. By making measurements faster, accurate and simpler this new technology could help solve one of the big challenges in quantum computing.
As quantum computers get bigger and more complex, good measurement systems like this one will be very important for making them work. This could help make computers that are practical and useful a reality.