Moore Foundation grantees at Harvard University have reached an important milestone in studying the phenomenon underpinning superconductivity, one of the most exciting phenomena in condensed matter physics.
Superconductors are materials that conduct electricity without resistance at extremely low temperatures. They are used for power transmission and transportation (such as in Maglev trains), but researchers are actively seeking high-temperature superconductors that can be used in more everyday applications.
To shed light on superconductivity, Markus Greiner, a professor of physics at Harvard and foundation grantee through the Emergent Phenomena in Quantum Systems (EPiQS) initiative, has developed a new tool called a quantum gas microscope. The tool generates ultracold atoms that can be used to investigate superconductivity in real materials.
For this study, Greiner and his team created a quantum antiferromagnet from an ultracold gas of hundreds of lithium atoms. Unlike typical magnets, in which the electron spins align, antiferromagnets have spins arranged in a checkerboard pattern (one pointing up, the next down). Scientists believe this arrangement may be a precursor to high-temperature superconductivity.
To investigate their antiferromagnet, the team trapped a cloud of lithium atoms in a vacuum and then cooled them to just 10 billionths of a degree above absolute zero. The study also provided snapshots of the antiferromagnet with enough detail to identify and extract information about individual atoms.
These researchers say the system serves as a special-purpose quantum computer that can simulate the complex physics of antiferromagnets and their transformation into superconductors.
The ultracold nature of this experimental setup suggests measuring the temperature at which onset of superconductivity occurs is tantalizingly close. In the near future, Greiner’s experimental approach may be able to provide direct insights into high-temperature superconductivity, an exciting prospect.
“We have created a model system for real materials … and now, for the first time, we can study this model system in a regime where classical computers get to their limit,” said Greiner. “Now, we can poke and prod our antiferromagnet. It’s a beautifully tunable system, and we can even freeze time to take a snapshot of where the atoms are. That’s something you won’t be able to do with an actual solid.”
Greiner’s grant is part of the EPiQS initiative’s Flexible Funding strategy, which seizes on timely opportunities to advance the field through projects with particularly high potential impact. These projects may include experimental tests of novel important theoretical concepts and highly innovative research endeavors that are unlikely to be supported through traditional funding channels due to their high-risk nature.
Read the full article in Nature here, and read a story about the Harvard team’s findings here.