The pseudogap could help explain why some materials can lose electrical resistance at high temperatures, which could be key to mastering the practical use of superconductivity.

The feat was made possible after the team developed a quantum simulation system that relied on high-quality gas, along with a measurement system described to have “unprecedented” stability by a peer reviewer.

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The team used high-quality unitary fermi gas made from lithium-dysprosium – a model with superfluid properties – to confirm the pairing pseudogap for the first time.

The platform developed by the USTC scientists holds promise for future quantum simulation research, the university said in a post on Chinese social media platform WeChat.

Their feat, which could also help to understand the mechanisms behind high-temperature superconducting, was outlined in a paper published in the journal Nature on Wednesday.

A peer reviewer described the findings as “remarkable and exciting.”

A fermi gas is a model made up of many non-interacting fermions – particles including electrons, protons and neutrons. They can be used to make quantum simulation models of “many-body systems”, containing many interacting particles.

Unitary fermi gases make ideal simulation platforms, as the interactions between the fermi atoms is strong, and they exhibit high controllability, according to Micius Salon, a news platform hosted by USTC.

Ultracold fermi gases are able to exhibit superfluidity at very low temperatures, similar to materials that exhibit superconductivity.

When a superconducting material is cooled, its electrons are believed to group together in pairs. Breaking apart these pairs to cease superconducting takes energy.

The existence of two states of energy where a material is either superconducting or not means there is a gap between the ground state and excited state of the electrons called the energy gap, according to Micius Salon.

In conventional superconductors, the energy gap exists below the phase transition temperature, which is when a material transitions to superconducting.

However, in high-temperature superconductors, an energy gap is still observed above the transition temperature, which is called the “pseudogap”, Micius Salon said.

This pseudogap in high-temperature superconductors could not be explained by the accepted theory behind how conventional superconductors work, according to USTC.

Within high-temperature superconductors made of copper oxides, studying this gap is complicated due to the material properties,so the researchers used ultracold fermi gases with superfluidity instead, according to the paper.

Scientists who study ultracold atoms have debated and sought to observe a pairing pseudogap for nearly two decades, according to the Chinese Academy of Sciences (CAS), the country’s top research institute.

“The study established the existence of a pairing pseudogap for the first time” within ultracold fermi gas, and the feat is a “step forward in using quantum simulations to solve important physical problems”, the USTC said in their WeChat post on Thursday.

The team’s findings “lend support for the role of preformed pairing as precursor to superfluidity,” according to the paper.

Their feat also lends support to the theory that the pseudogap observed within high-temperature superconductors is also the result of electron pairing rather than quantum order phases, according to the USTC.

Understanding the mechanisms behind this would be “a huge theoretical breakthrough” which could allow us to uncover the “key to practical superconductivity”, Micius Salon said on Thursday.

The research team had been working on the project for years, and had two major issues to resolve to make their most recent feat possible, the USTC post said.

The first was the development of a uniformly dense, high quality fermi gas. It took the team years to develop a method to prepare the gas for their simulation platform.

The second challenge was developing a stabiliser for large magnetic fields, which allowed them to implement a novel microwave spectroscopy scheme with high magnetic field stability, USTC said, referring to a technology that allowed them to analyse atoms.

Understanding why and how pseudogaps occur within high-temperature superconductors is important for furthering our understanding of the mechanisms behind how it works, according to CAS.

The team’s finding chimed with the coming Year of the dragon, CAS said, as it could be compared to the Chinese myth of “Carp Leaping Over a Dragon Gate”.

The illustration accompanying the paper’s release on USTC’s WeChat handle also alluded to the myth. It depicts two carps leaping together, each clasping a jade bead in its mouth, in a representation of the electron-pairing phenomenon.