Intel cooperated with QuTech to develop a quantum control method. (Photo: Tim Herman/Intel Corporation)
Intel’s quantum computing efforts are starting to show tangible results: two years after the company first unveiled its Horse Ridge cryogenic control c hip, researchers have demonstrated that the technology is delivering on its original promise, and paving the way for quantum computers to become more practical.
Intel’s efforts in the field of quantum computing have begun to bear fruit. Intel first announced its Horse Ridge low temperature control chip two years ago. Researchers recently demonstrated that the technology has achieved its initial promise, thus paving the way for quantum computers to move towards a more practical stage.
Practicality, in effect, is not quantum devices’ most remarkable trait. In their current format, quantum computers rely on quantum chips that need to be cooled down to extreme temperatures, in order to exert better control over the fragile qubits on the processor. Typically, qubits operate at 20 millikelvin, or about – 273 degrees Celsius – temperatures that are even colder than outer space.
Practicality is not a feature that quantum devices can show off at present. At present, quantum computers still need quantum chips cooled to extreme temperatures in order to better control the fragile qubits on the processor. Usually, qubits operate at a temperature of 20 millikelvin (about -273 degrees Celsius), which is even colder than outer space.
But to interact with the qubits, whether to control their behavior or read their state, flesh-and-bone scientists work in room-temperature environments, with room-temperature instruments. And since control electronics struggle to perform well at cryogenic temperatures, each qubit has to be linked to the instruments with a single wire.
However, when scientists interact with qubits (such as controlling the behavior of qubits or reading the state of qubits), they all do it at room temperature, and the instruments are also installed at room temperature. Due to the poor performance of control electronics at low temperature, each qubit must be connected to the instrument with a wire.
It’s easy to see why the set-up might become problematic as scientists contemplate the possibility of scaling up quantum computers to millions of qubit s. This hurdle has become known as the "wiring bottleneck".
It is not difficult to see that when scientists consider expanding the scale of quantum computers to millions of qubits, there may be some problems in such a setting. This obstacle is called "wiring bottleneck".
This is why, a few years ago, Intel teamed up with QuTech – a collaboration between Delft University of Technology and the Netherlands Organization for Applied Scientific Research – to work on another approach to the problem.
A few years ago, Intel and QUTECH (a cooperative project between Delft University of Technology and Dutch applied science research organization) began to cooperate to develop another method to solve this problem.
It took the form of a new control chip designed to withstand the cold and operate as close as possible to the quantum processor, which Intel unveiled for the first time in 2019. The device was named Horse Ridge – a reference to the coldest place in Oregon, which is also the state where the Intel lab resides.
The research of the two companies adopts a new form of control chip, which needs to resist the cold and run as close as possible to the quantum processor. Intel first announced the chip in 2019. The code name of the chip is Horse Ridge— — Horse Ridge is the coldest place in Oregon where Intel Labs is located.
Horse Ridge was built on Intel’s 22-nanometer FinFET Low Power technology, and was presented as a potential way to bring key control functions for quantum computer operations directly into the cryogenic refrigerator, closer to the qubits themselves.
Horse Ridge is based on Intel’s 22nm FinFET low-power technology. Horse Ridge aims to make the key control functions of quantum computer operation be placed in a low-temperature refrigerator, which can be closer to qubits.
The underlying premise was that, if Horse Ridge could achieve the same level of control as room-temperature instruments, then the wiring bottleneck could be significantly reduced.
But the basic premise is that Horse Ridge can reach the same control level as the room temperature instrument, so the bottleneck of wiring can be greatly reduced.
Horse Ridge was subsequently tweaked, and a second generation of the chip was showcased last year; but now, for the first time, Intel’s researchers have demonstrated that the technology is as capable of controlling qubits as its room-temperature-based equivalents.
Horse Ridge later made some improvements, and last year showed the second generation Horse Ridge chip. Now, for the first time, Intel researchers have proved that Horse Ridge technology can control qubits like its similar products based on room temperature.
The research team used Horse Ridge to run a two-qubit algorithm called the Deutsch-Jozsa algorithm, and found that the cryogenic chip performed well despite the cold environment, and achieved control of the qubits with a same level of fidelity (99.7%) as room-temperature electronics.
The research team used Horse Ridge to run a double qubit algorithm named Deutsch-Jozsa algorithm. The research team also found that despite the cold environment, the low-temperature chip performed well, and the qubit control was realized, with the fidelity (up to 99.7%) being the same as that of room-temperature electronic products.
"Our research results, driven in partnership with QuTech, quantitatively prove that our cryogenic controller, Horse Ridge, can achieve the same high-fidelity results as room-temperature electronics while controlling multiple silicon qubits," said Stefano Pellerano, principal engineer at Intel Labs.
Stefano Pellerano, chief engineer of Intel Laboratories, said, "The research results promoted by us in cooperation with QuTech Company prove quantitatively that our low-temperature controller Horse Ridge can achieve the same high-fidelity results as room-temperature electronic devices when controlling multi-chip qubits."
Horse Ridge is a silicon-based CMOS chip, and as such was designed with a technology similar to that used in conventional microprocessors. The device was adapted to ensure the right operation even at cryogenic temperatures, which enables the chip to manipulate the state of qubits thanks to radio frequency pulses.
Horse Ridge is a CMOS chip based on silicon, so the technology similar to the traditional microprocessor is adopted in the design. Horse Ridge device has been modified to ensure that it can operate correctly even at low temperature, and the chip can finally manipulate the state of qubits through RF pulses.
The qubits manipulated by Horse Ridge are also silicon-based, contrary to the type of qubits that can be found, for example, in IBM or Google’s quantum computers, which are superconducting qubits. While Intel initially pursued both approaches – superconducting as well as silicon qubits – the company’s recent efforts have ramped up in the latter.
The qubits manipulated by Horse Ridge are also based on silicon, as opposed to the type of qubits found in quantum computers such as IBM or Google, which are superconducting qubits. At first, Intel did both superconducting and silicon qubits, but recently it has strengthened its research work on silicon qubits.
This is because researchers are increasingly acknowledging that building quantum computers with techniques that are similar in nature to those used to produce most modern-day electronics could come with huge advantages when it comes to scaling the technology.
The reason is that researchers realize that if quantum computers can be built with technologies similar to those used to produce most modern electronic products, there will be great advantages in technology scale expansion.
What’s more: with both qubits and the controller chip fabricated in silicon, Intel’s researchers are hoping that it may be possible to one day fully integrate them both together in one die or package. This would greatly simplif y the wiring challenge of quantum and enable strides in quantum scalability.
More importantly, since both qubits and control chips are made of silicon, Intel researchers hope that one day they can be completely integrated into one chip or component. This can greatly simplify the quantum wiring and greatly improve the quantum scalability.
"These innovations pave the way for fully integrating quantum control chips with the quantum processor in the future, lifting a major roadblock in quantum scaling," said Pellerano.
Pellerano said, "These innovations pave the way for the complete integration of quantum control chips and quantum processors in the future and remove a major obstacle in quantum expansion."
With these new results, Intel is cementing the company’s position in the fast-evolving quantum ecosystem. While much of the focus remains on the qubits themselves, and on improving quantum processors, the Santa Clara giant has established that it is adopting a different course of action, instead working on developing the interconnects and control electronics that will create a quantum stack.
Intel is using these new achievements to consolidate its position in the rapidly developing quantum ecosystem. At present, most of the attention is still focused on the quantum bit itself and improving the quantum processor, but on the other hand, it shows that the Santa Clara-based technology giant is taking different action plans instead of developing the interconnection and control of creating quantum stacks.
Integrating those systems, according to Intel, will be as important a piece of the puzzle to achieve quantum practicality.
According to Intel, integrating these systems is bound to be an important part of realizing quantum practicability.