Scientists get closer to 4D quantum Hall effect with new method

Researchers from Tsinghua University, Peking University, and ShanghaiTech University are pursuing a pathway to realizing the four-dimensional quantum Hall effect by actively compensating for signal loss in topological insulators. The work centers on the topological magnetoelectric effect, described by the equation ΔP = e²/2hN_(Ch)^(2)ΔB, which links changes in polarization to magnetic fields and offers a condensed-matter analog to the 4D QHE. By introducing a tunable negative capacitance, the team recovered over 95% of the quantized charge signal from an initially half-attenuated state, providing a robust method for detecting minute signals and advancing the search for direct measurements of this elusive quantum state. Yuanze Li of Tsinghua University, Renfei…