Youssef Kora, PhD student in the Department of Physics. Photo supplied.
We’re all familiar with the traditional three phases of matter: solid, liquid, and gas. But when quantum mechanics are involved, these three states aren’t the full story—and a new study led by a 海角社区 graduate student explores how these phases are affected as quantum-mechanical effects come into play.
“We investigated the physics of quantum-mechanical systems of many interacting particles,” said , PhD student in the Department of Physics. “These particles are bosons, which means that they obey a certain type of quantum statistics: Bose-Einstein statistics. We studied the different phases of these systems, which are not limited to the familiar three—solid, liquid, and gas—but also include exotic quantum-mechanical phases such as superfluids.”
The researchers were able to obtain exact numerical results for the physical properties of these systems in a theoretical model, and mapped out diagrams of the phases as a function of pressure, temperature, and “quantumness,” studying how the transitions between phases evolve.
“Tuning the quantumness can be achieved by a variety of different ways, the simplest being looking at different isotopes of helium,” explained Kora. “Conducting experiments with lighter isotopes make quantum-mechanical effects more prominent in the dynamics of these particles. In this way, we can see how quantum-mechanical effects in turn affect the transition between phases of these systems.”
Researchers previously understood the phase diagram of a limited class of these systems, particularly those with heavier isotopes such as the highly abundant helium-4. But Kora and his colleagues were able to generalize these results to a broader range of systems.
“The most remarkable thing is the versatility of such a compact physical model to capture a broad class of condensed matter systems that exhibit a large range of physical behavior,” said Kora. “By tuning a single parameter, we can explore radically different physics, ranging from completely classical on one end, to ultra-quantum on the other.”
Kora’s research was supervised by , professor of physics in the Faculty of Science. The research also involved collaboration with researchers from the , the , and the .
This work was supported by the , a , and the , which is a grant from the Simons Foundation (grant number 651440). The researchers also received computing support from and the Flatiron Institute.
The paper, was published in . (doi: 10.1073/pnas.2017646117).