IBM's 3D qubit device brings quantum computing even closer

IBM says it has made a significant advance towards creating mind-bendingly powerful quantum computers with it superconducting 3D qubit device.

With experts hoping to construct a full working quantum computer in the next decade or so, the ability by IBM boffins to reduce errors in quantum processing and withhold information has made this even more likely.

Qubits, or quantum bits, are the basic units of information used to process information in a quantum computer.  Unlike ‘bits’ used in regular computers, which can switch between 0 and 1, quantum bits can be either 0 or 1.  Rather more perplexingly, the weird world of quantum mechanics means that they can also be both at the same time.

It is this ability to exist in multiple states that opens up potential for massively increased computing power.

To use one particularly brain-wrenching example of the power, most fast modern computers will allow a user to work on a small number of computations simultaneously. However, a single 250-qubit state could simultaneously contain more bits of information than there are atoms in the universe.

Such processing power is almost unbelievably faster than what is possible today, but with advances being made by IBM, the reality is almost within reach.

The number of qubits which are able to function is a lot smaller at the moment – just two or three.  But the possibility of putting these into a working computer has received a boost by reducing the number of errors in calculations made by previous attempts at quantum computers, and lengthening the time in which the qubits retain their quantum properties.

IBM scientists have now been able to achieve this with 3D superconducting qubits, which it believes are likely to work well in the transition to upscaling and manufacturing.

With this it was possible to get qubits to retain their quantum states for up to 100 microseconds, up to four times faster than what was previously possible. Crucially, this beats the threshold for enough time to allow for error correction in the qubits.

According to IBM, this leaves scientists with almost the minimum requirements for a full scale quantum computing system.

Intriguingly, the scientist reckon that we are now beginning to get out of the drawing board phase of development, with questions needing answering about processing demands for “error correction, I/O issues, feasibility, and costs with scaling”.

IBM says a practical quantum computing system is likely to be run on a “classical system” which can be connected to quantum computing hardware.

Mark Ketchen, manager of the Physics of Information group at IBM, tells TechEye that there is still a good way to go. “Our best guess is 20 years or more for commercially viable systems,” Ketchen said.

Ketchen believes that there are still significant hurdles to be jumped before we start thinking about full systems.

“On the quantum side, qubit metrics must still be significantly improved so that error correction can be implemented with practical overhead,” he said. “We are just now crossing the threshold where error correction can work. The overhead will be reduced significantly as metrics further improve. We have to perfect the technology to very rapidly read out the states of many of the qubits in parallel, also with a very low error rate and limited quantum noise. And we must figure out how to scale up.

“We are still at the level of a few qubits. How do we integrate many together? Hundreds, then thousands, perhaps a few million eventually, but billions are not needed such as the number of transistors in classical computing systems.”

Aside from the functionality of quantum processing there are also challenges in creating a working computer with the almost incomprehensible masses of data.

“On the classical side there are many difficult practical problems,” Ketchen said. “How do we package such a system at 15 milikelvin (mK) and handle the huge number of inputs and outputs to and from the quantum system? How do we handle the thermal engineering for such a large system running at 15 mK?

“A very special conventional computer will be required to operate the much more powerful quantum computer.”