Researchers at HZB have taken an important step toward bringing one of quantum physics' more unusual predictions closer to experimental reality. Fractons, exotic quasiparticles previously predicted in quantum spin liquids using highly generalized gauge field theories, have now also appeared in simulations of a more realistic quantum solid-state model. Quasiparticles emerge from the collective behavior of many interacting particles inside a solid.
For instance, vibrations moving through a crystal lattice can be described as quasiparticles known as phonons. Fractons are much more unusual. They appear at the corners of magnetic domain walls separating different spin arrangements, and their defining feature is their extremely limited mobility.
A single fracton is essentially unable to move by itself and can only be shifted through interactions with other fractons. That restriction could potentially be useful. Because fractons are so difficult to move, researchers have proposed that they might provide a way to store quantum information more robustly.
Physicists have predicted that fractons could occur in several types of systems, including quantum spin liquids. These are unusual states of matter in crystals where the magnetic moments of electrons never settle into a fixed arrangement, even at 0° K. Instead, they continue fluctuating in a way that resembles the constant motion of atoms in a liquid.
Bringing Fractons Into More Realistic Models So far, the fractons predicted in quantum spin liquids have not been directly observed in experiments. Until now, theoretical predictions of these particles had relied on highly generalized gauge field theories (rank-2 U(1) gauge theories). A study led by Professor Johannes Reuther and Dr.
Nils Niggemann has now moved the idea closer to experimental testing by showing that fractons can also emerge in a more realistic model of a quantum solid. Unlike classical models, these simulations account for quantum effects. Earlier work by the research group, however, ran into a major problem.
Extract — continue reading at the source.
