Superconductors are special materials that allow electricity to flow without any resistance, much like a frictionless highway for electrons. Inside these materials, strange quantum ripples called Higgs modes can appear. These ripples are collective vibrations in the electron field, behaving in a way that’s similar to the famous Higgs boson from particle physics. Higgs modes show up when a material shifts into its superconducting state, marking a dramatic change in how its electrons interact and organize.
Detecting photon echoes from superconducting Higgs modes is challenging because it requires maintaining and recovering the delicate phase patterns shared across multiple Higgs and quasiparticle excitations.
Scientists at Ames National Laboratory and Iowa State University have discovered a surprising “quantum echo” in a superconducting material, a type of quantum reverberation that hadn’t been observed before. This echo reveals hidden patterns in how particles behave at ultra-cold temperatures, offering a new window into the strange world of quantum mechanics.
The team used advanced terahertz (THz) spectroscopy techniques. They discovered a novel type of quantum echo, called the “Higgs echo,” in superconducting niobium materials used in quantum computing circuits.
Jigang Wang, a scientist at Ames Lab and lead of the research team, said, “Unlike conventional echoes observed in atoms or semiconductors, the Higgs echo arises from a complex interaction between the Higgs modes and quasiparticles, leading to unusual signals with distinct characteristics.”
Dr. Wang and his team discovered that Higgs echoes in superconductors can function as a quantum memory. These echoes don’t just bounce back; they also remember hidden quantum patterns within the material. By firing carefully timed pulses of terahertz (THz) radiation, the researchers were able to trigger and observe these echoes. Even more impressively, they found that these echoes could be used to encode, store, and retrieve quantum information, making the material behave like a quantum hard drive.
This research demonstrates that scientists can now control and observe quantum coherence, the delicate balance of quantum states, within superconductors. That’s a big deal, because it opens the door to new ways of storing and processing quantum information, potentially powering the next generation of ultra-fast, ultra-secure quantum technologies.
“Understanding and controlling these unique quantum echoes brings us a step closer to practical quantum computing and advanced quantum sensing technologies,” said Wang.
Journal Reference:
- Chuankun Huang, Martin Mootz, Liang Luo, Di Cheng, Avinash Khatri, Joong-Mok Park, Richard H. J. Kim, Yihua Qiang, Victor L. Quito, Yongxin Yao, Peter P. Orth, Ilias E. Perakis, Jigang Wang. Discovery of an unconventional quantum echo by interference of Higgs coherence. Science Advances, 2025; 11 (26) DOI: 10.1126/sciadv.ads8740