Ultracold Molecules Hold Promise for Quantum Computing
Researchers have taken an important step toward the long-sought goal of a quantum computer, which in theory should be capable of vastly faster computations than conventional computers for certain kinds of problems. The new work shows that collections of ultracold molecules can retain the information stored in them for hundreds of times longer than researchers have previously achieved in these materials.
“The most amazing thing is that these molecules are a system which may allow realizing both storage and processing of quantum information using the very same physical system,” said Sebastian Will, assistant professor of physics at Columbia University, who worked on the study during his years as a research scientist at MIT. “That is actually a pretty rare feature that is not typical at all among the qubit systems that are mostly considered today.”
The new materials are able to hold information longer because the researchers used internal quantum states of the molecule that are particularly insensitive to perturbations from the outside world. These quantum states don’t “jitter” much if there are magnetic or electric fields around the molecule. Usually, fluctuating magnetic fields, electric fields or collisions with other particles destroy storage time for quantum information in typical systems. “Our molecules are largely immune to all of these ‘bad’ influences,” Will said.
The next step, he added, will be to ‘talk’ to individual molecules. “Then we are really talking quantum information,” Will said. “If we can trap one molecule, we can trap two. And then we can think about implementing a ‘quantum gate operation’ — an elementary calculation — between two molecular qubits that sit next to each other.”