(SpectrumIEEE) Toronto-based Xanadu announced the release of the world’s first publicly available photonic quantum computing platform on September. Applicants can access 8, 12, and soon 24 qubit machines over the cloud.
According to Christian Weedbrook, Xanadu’s founder and CEO, the company can roughly double the number of qubits in its cloud systems every six months. In the coming months, Xanadu will release a blueprint for photonic quantum computing that is essentially a primer on “how to scale to millions of qubits in a fault-tolerant manner,” says Weedbrook.
Quantum computers that rely on qubits based on photons can, in principle, operate at room temperature. They can also readily integrate into existing fiber optic–based telecommunications infrastructure, potentially helping connect quantum computers together into powerful networks and even a quantum Internet. With the addition of so-called “time multiplexing” architectures, photonic quantum computing can in principle scale up to millions of qubits.
Xanadu’s strategy, known as continuous variable quantum computing, does not employ single-photon generators. Instead, the company relies on so-called “squeezed states” consisting of superpositions of multiple photons.
The classic approach to photonic quantum computing is linear optical quantum computing relies on qubits each based on a single photon. This strategy manipulates photons with mirrors, beam splitters, and phase shifters. Single photon detectors are then used to help read the results of what these devices have done. The problem with this approach is that single photons are difficult to experiment with, generally limiting this strategy to a handful of photons, Weedbrook says.

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