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13.12.2023 20:53, Gennady Detinich
Recently, the US Defense Advanced Research Projects Agency (DARPA) summed up the results the first phase of the ONISQ program, which was supposed to select the basis for the first generation of quantum computers for military needs. Qubits from Rydberg neutral atomsin the applied study of which scientists from Harvard University under the guidance of MIPT graduate Professor Mikhail Lukin succeeded.
Image source: DARPA
The ONISQ program or Optimization with Noisy Intermediate-Scale Quantum, which can be translated into Russian as optimization with noisy medium-scale quantum systems, started in May 2020. Among other systems, other variants of qubits were considered, including the well-studied superconducting qubits and qubits made of charged atoms (ions).
“Rydberg qubits have the useful characteristic of being homogeneous in their properties – this means that each qubit is indistinguishable from the next in its behavior, said Dr. Mukund Vengalattore, ONISQ Program Manager for DARPA’s Defense Sciences Division. “This is not the case for other platforms, such as superconducting qubits, where each qubit is unique and therefore not interchangeable.”
Cooled neutral atoms easily arrange themselves into arrays and can randomly program quantum circuits or algorithms using optical tweezers (a high-density laser beam) that moves the qubits into desired positions before starting calculations. The relative simplicity and reliability of working with neutral atoms was proven by Lukin’s team in a recent paper, where they showed error-free operation of a quantum system of 48 logical qubits on a system of 280 physical qubits.
To create a chain of 48 logical qubits on superconducting qubits would require up to 5000 physical qubits, which today seems problematic even taking into account the recent announcement of the IBM Condor processor with 1121 qubits.
Lukin’s team made do with a simpler quantum system, and all 48 logical qubits were reportedly entangled, which was DARPA’s choice. True, from the announcement it is not clear what relation the agency’s team has to the work done by scientists.
“If someone had predicted three years ago, when the ONISQ program began, that Rydberg neutral atoms [возбужденный атом с одним или несколькими электронами, имеющими очень высокое главное квантовое число] can function as logical qubits, no one would believe it, said Dr. Guido Zuccarello, DARPA technical advisor. “This is an opportunity for DARPA to bet on the potential of these lesser-studied qubits alongside more well-studied ions and superconducting circuits.” As a research program, ONISQ has given scientists the freedom to explore unique and novel applications beyond simple optimization. As a result, the Harvard-led team was able to harness the much greater potential of these Rydberg qubits and turn them into logic qubits, which is a very significant discovery.”
2023-12-13 17:53:38
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