Today, in an experimental first, a team of researchers observed this superradiant phase transition (SRPT) for the first time. This phenomenon was first hypothesized almost seventy years ago by Princeton physicist Robert H. Dicke. This astonishing finding only came about in a uniquely engineered crystal. The creation of this material is an important breakthrough in the field of quantum physics and includes promising applications for quantum computing, sensors and more robust communication technologies.
One of the special features of the SRPT is the peculiar state of matter that is produced when intense light-matter interactions are combined with quantum features. Specifically, it happens when highly energized atoms produce radiation more quickly than normal atomic processes. Klaus Hepp and Elliot H. Lieb explained this transition in fuller detail in 1973. Specifically, they showed in a rigorous way that it exists, going against the prior notion that SRPT was a no-go theorem.
For the study, the researchers observed the SRPT in a crystal made of erbium, iron and oxygen. To do this experiment, the crystal had to be cooled to frigid temperatures of -457 °F (-271.67 °C) nearing absolute zero. What’s more, they superimposed a magnetic field 100,000 times stronger than that of the Earth to trigger the transition.
Dasom Kim, one of the lead researchers, detailed the experiment’s significance, stating, “We established an ultrastrong coupling between these two spin systems and successfully observed a SRPT, overcoming previous experimental constraints.”
At the center of the SRPT is quantum squeezing, a process where uncertainty in one measurable quantity is reduced. By minimizing the effects of quantum noise, this reduction in measurement precision represents a monumental step forward. Kim further explained the foundation of this discovery by saying, “Near the quantum critical point of this transition, the system naturally stabilizes quantum-squeezed states — where quantum noise is drastically reduced — greatly enhancing measurement precision.”
The impact of this research goes well beyond mere intellectual curiosity as it could be a harbinger for more robust applications in emerging quantum technologies. The ability to manipulate light and matter at this level could lead to advancements in quantum computing and precision measurements.
In 1954, Dicke put forward his initial model. He conceptualized superradiance as a product of interactions between quantum vacuum fluctuations and matter fluctuations, in which quantum light fields are present even in a vacuum. These latest observations are the first empirical test that corroborates this theory, scientifically reaffirming Dicke’s innovative work to the field.
Researchers are still working to expand the possibilities of quantum mechanics. This observation of SRPT is an important milestone in our fundamental understanding of how light interacts with matter. Their results might someday lead to innovative technologies that take advantage of these principles to be used in the real world.
