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Researchers Succeed in Decoupling Qubits From Environment

"The big step forward here is that we were able to decouple individual qubits from the environment, so they retain their information, while preserving the coupling between the qubits themselves" said Viatsheslav Dobrovitski, a physicist at the U.S. Department of Energy's Ames Laboratory.

The team built what they call a hybrid system for quantum processing that has different types of qubits for different purposes. In this case, there was an electron and a nucleus with measurable magnetic states. "This type of hybrid system may be particularly good for quantum information processing because electrons move fast, can be manipulated easily, but they also lose quantum information quickly. Nuclei move very slow, are difficult to manipulate, but they also retain information well," said Dobrovitski. "You can see an analogy between this hybrid quantum system and the parts of a classical computer: The processor works fast but doesn't keep information long, while the memory works slowly but stores information for a long time."

Decoupling of qubits from their environment has been considered for some time to be a method to increase the time of quantum data being retained. However, so far the decoupling was an all-or-nothing question and even the qubits were decoupled from each other. Dobrovitski said that he found a "narrow window of opportunity where both the electron and nucleus can be decoupled from their environment, while retaining their relationship to each other." As a result, both qubits can store their information reliably. The scientist believes that the discovery will open a door to robust quantum computation with solid-state devices.