Microsoft's New Quantum Computer Shows Why They Are So Hard to Build

Microsoft scientists claim to have made an advance that brings practical quantum computers a step closer to reality, but experts say the field is still in its infancy. 

Teams around the world are racing to build quantum computers that could outperform classical computers. But high error rates have hindered efforts to build a reliable quantum computer. Now Microsoft researchers say they have made a breakthrough that could make quantum computers more dependable. 

"While Microsoft has recently shared some interesting experimental results, they have not yet demonstrated an operational qubit, much less multiple qubits executing a quantum circuit," Paul Lipman, Chief Commercial Officer at the quantum computing company Infleqtion, told Lifewire via email. "However, we should applaud all efforts toward the eventual goal of a large-scale, error-corrected quantum computer. Such a device will transform the world for the better, and it is far too early in the race to say which approach will ultimately prove out. In fact, it may well be that different approaches prove appropriate for different use cases."

Quantum Leap?

The Microsoft engineers reported that they had engineered a new way to represent a logical qubit with hardware stability. The device can induce a phase of matter characterized by Majorana zero modes, a fermion. Using this type of matter can aid in producing quantum supercomputers with low error rates. 

Microsoft claims that they have created a way to represent qubits and superposition combined with the hardware stability that would be required to "legitimately start moving towards a commercial quantum computer," Michael Nizich, the director of the  Entrepreneurship & Technology Innovation Center at the New York Institute of Technology, said in an email to Lifewire. 

"To date, the complex hardware solutions used in research-based quantum computers have been prone to errors due to their complexity, and Microsoft's discoveries may allow the next phase of discussions regarding commercially available quantum processors and, more importantly, for Microsoft, Quantum Operating Systems (QOS), to begin." 

At the heart of quantum computing is the physics of a viable qubit, the quantum version of the classic binary bit, Bill Lawrence, the CISO of the cybersecurity company Hopr told Lifewire via email. Qubits operate in the realm of quantum physics, while classical physics is the home of conventional computing.

Conventional computers work at room temperature, and the 'Bit' is the basic unit for storage and computation. It is either a '1' or a '0,' and strings of bits can represent numbers, characters, pictures, audio, etc., that can be stored and manipulated by the conventional computer's processors.  

Quantum computers work in the realm of quantum subatomic physics, where something can be a particle or a wave at the same time, Lawrence said. Objects at this tiny scale can be in two places simultaneously, and there are limits to how accurately the value of a physical quantity can be predicted before its measurement, given a complete set of initial conditions. Quantum computers use qubits that deal with all possible values of each qubit simultaneously but in a fashion that the quantum processor can interpret to solve complex problems quickly.

Herding Qubits

Using qubits in computers is incredibly difficult. Qubits are extremely sensitive to noise and hold their quantum state typically for very short periods, Lipman pointed out. He said the largest quantum computers currently available consist of only a few hundred noisy physical qubits. 

Dozens of competing companies are pouring research money into qubit technologies, and there are likely over a dozen very different qubit technology approaches underway, Lawrence said.

"Microsoft's claim does appear to be interesting but also controversial, as it claims to be solving the very important error-rate issues by relying on a newly discovered 'elusive particle,'" he added. "This would imply that significant research and development will still be needed."

Creating a commercially valuable quantum computer will require millions of near-perfect qubits, with exquisite control of their quantum state and noise, and sophisticated approaches to error mitigation and error correction, Lipman said. 

"The world's collective quantum computing efforts have been described as a 'moon shot,'" he added. "However, the scientific and engineering challenges required to deliver on this quantum computing dream are arguably far harder than those required to put people on the moon."