Intel’s director of quantum hardware, Jim Clarke, sees a path with their current quantum technology to perhaps 1000 qubits. This is the highlights of what he told Spectrum IEEE.
Intel is working on multiple qubit technologies. They were initially exclusively superconducting chips.
The size of the qubits in silicon spin qubit is a million times smaller.
The silicon spin qubit is a conventional transistor with a steady stream of current flowing through it. They have a single electron trapped in the transistor. That single electron can have one of two states: spin up or spin down. Those are the two states of the qubit. Intel is creating a series of single-electron transistors and coupling them together using their advanced transistor process technology.
Intel’s best process technology for transistors would be able build the best spin qubit.
Right now, they are linear arrays of quantum dots. Intel is trying to basically prove the physics of larger devices. They will next make them into arrays of qubits.
It should be about 5 years to 1000 qubit chips with superconducting technology.
It should be about 10 years to million qubit chips. This would likely be with silicon spin qubits.
Intel is currently making 5 wafers per week of silicon spin technology.
Spin qubits, in comparison to their superconducting counterparts, offer a few advantages in addressing these challenges.
They’re small and strong: Spin qubits are much smaller in physical size and their coherence time is expected to be longer – an advantage as researchers aim to scale the system to the millions of qubits that will be required for a commercial system.
They can function at higher temperatures: Silicon spin qubits can operate at higher temperatures than superconducting qubits (1 kelvin as opposed to 20 millikelvin). This could drastically reduce the complexity of the system required to operate the chips by allowing the integration of control electronics much closer to the processor. Intel and academic research partner QuTech* are exploring higher temperature operation of spin qubits with interesting results up to 1K (or 50x warmer) than superconducting qubits. The team is planning to share the results at the American Physical Society (APS) meeting in March.
Intel manufacturing know-how: The design of the spin qubit processors highly resembles the traditional silicon transistor technologies. While there are key scientific and engineering challenges remaining to scale this technology, Intel has the equipment and infrastructure from decades of fabricating transistors at scale.
In Feb 2018, Intel presented on its success creating a two-qubit spin-based quantum computer that can be programmed to perform two simple quantum algorithms.
Intel has invented a spin qubit fabrication flow on its 300 mm process technology using isotopically pure wafers sourced specifically for the production of spin-qubit test chips. Intel produces many wafers per week, each with thousands of small qubit arrays.
Sources- IEEE Spectrum, Intel, Youtube