Tiny Mechanical Devices Could Power Quantum Computers

It’s the same tech that’s in your phone

  • Simple mechanical devices inspired a recent advance in quantum computing. 
  • Stanford researchers invented a computing technique using acoustic devices that harness motion. 
  • Quantum computing has made significant progress in recent years, most notably with the demonstration of so-called quantum supremacy.
Angled-view photograph of the fully packaged device. The top (mechanical) chip is secured facedown to the bottom (qubit) chip by an adhesive polymer.
Angled-view photograph of the fully packaged device. The top (mechanical) chip is secured facedown to the bottom (qubit) chip by an adhesive polymer.

Agnetta Cleland

Practical quantum computers may be a step closer to reality thanks to new research inspired by simple mechanical devices.

Stanford University researchers claim to have developed a critical experimental device for future quantum physics-based technologies. The technique involves acoustic instruments that harness motion, such as the oscillator that measures movement in phones. It’s part of a growing effort to harness the strange powers of quantum mechanics for computing. 

"While many companies are experimenting with quantum computing today, practical applications beyond 'proof of concept' projects are probably 2-3 years away," Yuval Boger, the chief marketing officer of the quantum computing company Classiq told Lifewire in an email interview. "During these years, larger and more capable computers will be introduced, and software platforms that allow taking advantage of these upcoming machines will be adopted."

The Role of Mechanical Systems in Quantum Computing

The researchers at Stanford are trying to bring the benefits of mechanical systems down to the quantum scale. According to their recent study published in the journal Nature, they accomplished this goal by joining tiny oscillators with a circuit that can store and process energy in a qubit, or quantum 'bit' of information. The qubits generate quantum mechanical effects that could power advanced computers. 

"The way reality works at the quantum mechanical level is very different from our macroscopic experience of the world."

"With this device, we’ve shown an important next step in trying to build quantum computers and other useful quantum devices based on mechanical systems," Amir Safavi-Naeini, the senior author of the paper, said in the news release. "We’re in essence looking to build ‘mechanical quantum mechanical’ systems."

Making the tiny mechanical devices took a lot of work. The team had to make hardware components at nanometer-scale resolutions and put them onto two silicon computer chips. The researchers then made a kind of sandwich that stuck the two chips together, so the elements on the bottom chip faced those on the top half. 

The bottom chip has an aluminum superconducting circuit that forms the device’s qubit. Sending microwave pulses into this circuit generates photons (particles of light), which encode a qubit of information in the machine. 

Unlike conventional electrical devices, which store bits as voltages representing either a 0 or a 1, qubits in quantum mechanical devices can also represent combinations of 0 and 1 simultaneously. The phenomenon known as superposition allows a quantum system to exit in multiple quantum states at once until the system is measured.

"The way reality works at the quantum mechanical level is very different from our macroscopic experience of the world," said Safavi-Naeini.

A single quantum of motion, or phonon, is shared between two nanomechanical devices, causing them to become entangled.
A single quantum of motion, or phonon, is shared between two nanomechanical devices, causing them to become entangled.

Agnetta Cleland

Progress in Quantum Computing

Quantum technology is advancing rapidly, yet there are hurdles to clear before it’s ready for practical applications, Itamar Sivan, the CEO of Quantum Machines, told Lifewire in an email interview. 

"Quantum computing is probably the most challenging moonshot we as a society are occupied with right now," Sivan said. "For it to become practical, it will require significant progress and breakthroughs in multiple layers of the quantum computing stack."

Currently, quantum computers are haunted by noise which means that, over time, qubits become so noisy that we have no way to understand the data that is on them, and they become useless, Zak Romaszko, an engineer with the company Universal Quantum said in an email. 

"In practice, this means that algorithms for quantum computers are limited to only a small amount of time or number of operations before failure," Romaszko said. "It is not clear whether this noisy regime can produce practical results, although several researchers believe simulating basic chemicals is within reach."

Quantum computing has made significant progress in recent years, most notably with the demonstration of so-called 'quantum supremacy' in which a quantum computer performed an operation that the authors claimed would have taken a regular machine about 10,000 years to complete. "There’s been some debate around whether a regular computer would have taken that long, but it’s still a remarkable demonstration," Romaszko said.  

Once the technical hurdles are solved, Sivan predicts that within a few years, quantum computing will start to have a significant impact on everything from cryptography to vaccine discovery.  "Imagine how different the Covid-19 pandemic would have been if quantum computers were able to help discover a vaccine in a fraction of the time," he said. 

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