Quantum fluctuations blurred fractons in octahedral solid-state system

Quasiparticles, which mathematically represent excitations in solids, offer a fascinating avenue of exploration. Among these, fractons stand out as intriguing candidates due to their fractional spin excitations and immobility. They present an exciting possibility for secure information storage, as they lack kinetic energy and remain stationary. However, under certain conditions, fractons can be moved by piggybacking on another quasiparticle.

Fractons have emerged from an extension of quantum electrodynamics, where electric fields are treated as tensors, detached from real materials. Professor Johannes Reuther, a theoretical physicist at the Freie Universität Berlin and HZB, explains that finding simple model systems is crucial for future experimental observations of fractons. Consequently, they modeled octahedral crystal structures with corner atoms that interact antiferromagnetically. Through these models, they identified characteristic pinch points in spin correlations, which could potentially be observed experimentally using neutron experiments.

However, previous work treated spins as classical vectors, disregarding quantum fluctuations. To address this, Professor Reuther, along with Yasir Iqbal from the Indian Institute of Technology and doctoral student Nils Niggemann, incorporated quantum fluctuations into the calculations for this octahedral solid-state system. These complex numerical calculations aimed to capture the essence of fractons.

To their surprise, the results showed that quantum fluctuations did not enhance the visibility of fractons. Instead, they completely blurred the fractons, even at absolute zero temperature. Undeterred, the researchers plan to develop a model that allows them to regulate quantum fluctuations. This intermediate model will bridge classical solid-state physics and the previous simulations, enabling a more detailed study of fractons within the framework of extended quantum electrodynamics.

While no materials that exhibit fractons are currently known, the researchers hope that the next model will provide more precise indications regarding the crystal structure and magnetic interactions required. This could pave the way for experimental physicists to design and measure such materials. Professor Reuther acknowledges that practical applications of these findings may not be realized in the near future but believes that in the coming decades, they could lead to a significant quantum leap, introducing entirely new properties.

The findings of this research have been published in the journal Physical Review Letters.

Source: Helmholtz Association of German Research Centres

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