‘Massive atoms’ enable quantum processing and communication into one


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Researchers at MIT have introduced a quantum computing architecture that can perform low-error quantum computations, rapidly sharing quantum information between processors. The work represents a major advance towards a complete quantum computing platform.


Prior to this discovery, small-scale quantum processors have successfully functioned at a rate much faster than classical computers. However, quantum information between distant parts of a processor is difficult to control. In classical computers, wired interconnects are used to forward information back and forth across processors during computation. In a quantum computer, however, the information itself is quantum mechanical and delicate, requiring fundamentally new strategies to simultaneously process and communicate quantum information on a chip.

“One of the main challenges in scaling quantum computers is to be able to interact with each other when quantum bits are not co-located,” says William Oliver, a fellow and associate professor of electrical engineering and computer science, MIT Lincoln Laboratory. Director of Research Laboratory for Electronics. “For example, nearest-neighbor qubits can interact easily, but how do I create ‘quantum interconnects’ that connect cube to distant locations?”

The answer lies beyond traditional light-matter interactions.

While natural atoms are small and point-like with respect to the wavelength of light, which they publish in a paper published in the journal. Nature, Researchers point out, this should not be the case for superconducting “artificial atoms”. Instead, they have constructed “giant atoms” from superconducting quantum bits, or qubits, connected to a microwave transmission line or waveguide in a tunable configuration.

This allows researchers to adjust the strength of the qubit – waveguide interactions to protect fragile quabs from dichohanes, or a type of natural decay that would be hastened by the waveguide while they conduct high-fidelity operations. Once those computations are performed, the strength of the quat-waveguide couplings is rechecked, and quantum quantum data are able to be released as photons, or light particles, in waves.

MIT’s graduate fellow and first author of the paper, Bharat Kannan, says, “Coupling a queti to a waveguide is usually bad enough for qubit operations, because doing so can significantly reduce the quet’s lifetime.” “However, the waveguide is essential for releasing and routing quantum information during the processor. Here, we have shown that it is possible to maintain the cohesion of the qube even if it is strongly connected to a waveguide. We then have the capability. Is. Determine when we want to release the information stored in Quiet. We have shown how giant atoms can be used to turn on and off interactions with waveguides. “

The system realized by the researchers represents a new regime of light-matter interaction, the researchers say. Unlike models that treat atoms as point-like objects, they are smaller than the wavelengths of light with which they are superconducting, or superfluous atoms, essentially large electrical circuits. . When coupled with the waveguide, they form a structure as large as the wavelength of the microwave’s light with which they make contact.

Microwaves emit their information in the form of microwave photons at many locations along the wave wave, such that photons interfere with each other. This process can be tailored to elicit destructive interference, which means that the information in the qubit is preserved. Furthermore, even when no photons are actually free of giant atoms, many qubits with waveguides are still capable of interacting with each other to perform the operation. Across, Québets are strongly associated with waveguides, but due to this type of quantum interference, they can remain unaffected by this and remain protected from decoynes, while single and two-quart operations are performed with high fidelity Huh.

“We use quantum interference effects enabled by giant atoms, preventing them from dropping their quantum information to the waveguide until we need to.” Says Oliver.

“This allows us to experimentally investigate a novel regime of physics that is difficult to reach for natural atoms,” says Kannan. “The effects of the giant atom are extremely clean and easy to observe and understand.”

Kannan said that there is a lot of scope for further research in this work.

“I think one of the surprises is actually the relative ease by which superconducting qubits are able to enter this massive nuclear regime.” He says. “The tricks we employ are relatively simple and, as such, one can imagine using it for further applications without a great deal of extra overhead.”

The coherence time of the quanties contained in the massive atoms, which means that they were in a quantum state, was about 30 microseconds, for a qubit not coupled to a uniform waveguide between 10 and 100 microseconds. There is a limit. For the researchers.

Additionally, research shows two-qubit entanglement operations with 94 percent fidelity. This represents the first time researchers have cited two-qubit fidelity strongly coupled to a waveguide, since the fidelity of such an operation is often lower in such architecture using conventional small atoms . With greater calibration, operation tune-up procedures, and optimized hardware design, Kannan says, fidelity can be improved further.


The array of strontium Rydberg atoms shows promise for use in quantum computers


more information:
Waveguide quantum electrodynamics with superconducting artificial giant atoms, Nature (2020). DOI: 10.1038 / s41586-020-2529-9, www.nature.com/articles/s41586-020-2529-9

Provided by Massachusetts Institute of Technology

Quotes: ‘Giant atoms’ enable quantum processing and communication in one (2020, 29 July) on 29 July 2020 from https://phys.org/news/2020-07-giant-atoms-enable-quantum.html get

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