Two major steps forward for large-scale quantum computing just took place. Physicists from the MIT-Harvard Center for Ultracold Atoms (CUA) and elsewhere mastered the programmable quantum simulator, which can operate with 256 quantum bits (“qubits”). The company ColdQuanta also successfully created a 100-qubit quantum processor by cooling atoms down to “near absolute zero” and then controlling them with lasers. Their system, said experts, compares with other quantum systems built by leading players in the field.
SciTech Daily reports that the 256-qubit simulator “moves the field into a new domain where no one has ever been to thus far,” according to Harvard Quantum Initiative co-director Mikhail Lukin, who is also the George Vasmer Leverett Professor of Physics.
The study’s lead author, physics graduate student Sepehr Ebadi, said, “it is the combination of system’s unprecedented size and programmability that puts it at the cutting edge of the race for a quantum computer.” “The number of quantum states that are possible with only 256 qubits exceeds the number of atoms in the solar system,” he said.
The Harvard Quantum Initiative “uses a significantly upgraded version of a platform the researchers developed in 2017, which was capable of reaching a size of 51 qubits … [by] the researchers captur[ing] ultra-cold rubidium atoms and arrang[ing] them in a specific order using a one-dimensional array of individually focused laser beams called optical tweezers.”
This new system “allows the atoms to be assembled in two-dimensional arrays of optical tweezers,” thus increasing the system size from 51 to 256 qubits.
“The workhorse of this new platform is a device called the spatial light modulator, which is used to shape an optical wavefront to produce hundreds of individually focused optical tweezer beams,” said Ebadi. “These devices are essentially the same as what is used inside a computer projector to display images on a screen, but we have adapted them to be a critical component of our quantum simulator.”
Researchers use lasers to gain “complete control over the positioning of the atomic qubits and their coherent quantum manipulation.” “This work enables a vast number of new scientific directions,” Ebadi said. “We are nowhere near the limits of what can be done with these systems.”
ZDNet reports that ColdQuanta’s system, codenamed Hilbert, will debut later this year “after final tuning and optimization work.” In three years, the company plans to create a system of 1,000+ qubits, which “aligns with IBM’s roadmap for quantum hardware, which should see the company releasing a 1,121-qubit quantum computer in 2023.”
ColdQuanta president of quantum computing Paul Lipman said that, “in some respects cold atom is the new kid on the block, but we believe it has great promise in terms of scalability.” Although Google and IBM supercomputing processor also bring qubits down to zero kelvin, ColdQuanta’s process brings the atoms down to the microkelvin level, “a thousand times colder than in the superconducting method.”
ColdQuanta has a “long-standing partnership with the Defense Advanced Research Projects Agency (DARPA), which awarded ColdQuanta a total $7.4 million to develop a scalable cold-atom-based quantum computer for defense applications.” Hilbert will initially be available over the company’s private cloud, with eventual accessibility via AWS, Azure and Google Cloud.