A New, Simpler Quantum Computer Runs at Room Temperature

And it uses components already commercially available.
Chris Young

Engineers at Stanford University have demonstrated a new, simpler design for a quantum computer that could help practical versions of the machine finally become a reality, a report from New Atlas reveals.

The new design sees a single atom entangle with a series of photons, allowing it to process and store more information, as well as run at room temperature — unlike the prototype machines being developed by the likes of Google and IBM.

The new design uses simple components

Quantum computers rely on qubits rather than the ones and zeroes, or bits, of classical computing. Qubits can exist in three different states — a one, a zero, or a superposition of one and zero simultaneously — meaning they can, in theory, carry out computations it would take classical computers thousands of years to achieve. 

Though quantum computers have the capacity to perform such complex tasks, they have so far been hindered by their sensitivity to heat and vibrations — a problem that means they have to be kept at temperatures close to absolute zero. 

The Stanford team says their design does away with a lot of the complexity that results in greater sensitivity to external disturbances. It is essentially a giant photonic circuit made using a fiber optic cable, a beam splitter, two optical switches, and an optical cavity. These are used to make the two main components of the machine: a storage ring out of the fiber optic cable, and a scattering unit. 

"Normally, if you wanted to build this type of quantum computer, you’d have to take potentially thousands of quantum emitters, make them all perfectly indistinguishable, and then integrate them into a giant photonic circuit," Ben Bartlett, lead author of the study explains in a press statement. "Whereas with this design, we only need a handful of relatively simple components, and the size of the machine doesn't increase with the size of the quantum program you want to run."

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Harnessing quantum teleportation

The information in the machine is represented via the direction of the photons. One direction represents one, the other zero, and both at the same time (via the effects of quantum superposition) represent the third state. All information is encoded with a laser into a single atom, which is entangled with the photons. As the atom can be reset and reused, the computer's power can be scaled by simply adding photons into the ring. This eliminates the need to build several physical logic gates and, therefore, massively reduces the complexity of the machine.

"By measuring the state of the atom, you can teleport operations onto the photons," says Bartlett. "So we only need the one controllable atomic qubit and we can use it as a proxy to indirectly manipulate all of the other photonic qubits."

Perhaps one of the greatest benefits of the Stanford team's new system is that it can operate at room temperatures, meaning it may help to vastly reduce the complexity of these machines, which promise to revolutionize the problem-solving capacity of computers.