superconducting qubits last 10 times longer

Superconducting quantum technology has long held promise for bridging the gap between existing electronic devices and the subtle quantum world behind them. Unfortunately, progress in ensuring the stability of critical processes has stalled over the past decade.

Now, a significant step forward has finally been taken, thanks to University of Maryland researchers who have created superconducting qubits that last 10 times longer than before.

Qubits are so useful in computing because their quantum properties are entangled in ways that are mathematically convenient for solving certain complex algorithms, solving selected problems in moments that would take other technology decades or more.

Unfortunately, these critical properties not only get entangled with other qubits – they can mix with anything in their environment, often before their valuable information can be measured.

Now researchers have built what is called a Fluxonian qubit that can store information for 1.43 milliseconds. This may seem like a very short time, but it’s a 10x improvement over the previous record.

There are several ways to build a qubit, and each approach has its proponents.

Fluxonium is a kind of qubit based on operations at critical nodes in a superconducting circuit.

One of the big advantages of using superconducting systems to measure the quantum properties of electrons is that they are already based on electronic circuits – something we have a lot of manufacturing experience with.

This is one of the reasons why Fluxonian qubits are, in theory, better suited for large systems and error reduction. But until now, the coherence time (the time that data can be recorded) has been too short to be useful.

This latest advance brings fluxonium qubits back into the game with transmon qubits, which are the type of superconducting qubit currently favored by companies like Google and IBM for their quantum computers.

“Remarkably, even in the millisecond range, the coherence time is limited by material absorption and can be further improved with more stringent fabrication,” the researchers write in their published paper.

“Our demonstration could be useful for error suppression in the next generation of quantum processors.”

In other words, the researchers are confident that Fluxonium qubits can go even further in terms of coherence and stability. This will be important as scientists seek to scale their quantum computing systems using a variety of metrics.

The key to improvement here was adjustments to the operating frequency and circuit parameters, which increased the qubit’s relaxation time: the time it takes between its possible states, during which data can be recorded.

Clearly, there is still a lot of work to be done to make qubits usable in practice – most of the time they still need ultra-low temperatures to work, for example – but if we jump ahead 10x with each new research, our quantum computing future could come faster. than we think.

Study was published in Physical Review Letters.