Fig. 4: AGB skyrmion bags for topological information encoding.

a Example of encoding information within a single skyrmion bag containing four enclosed skyrmions, each with a skyrmion number ranging from −2 to 2. The chirality of the enclosing skyrmion defines the reading direction for the internal skyrmion numbers. Starting from the rightmost skyrmion as \(\alpha\), the values \((\alpha ,\beta ,\gamma ,\delta )\) are read sequentially along the direction indicated by gray arrows. These four values form two pairs, each encoding one 16-bit number, thereby enabling ASCII character encoding (see Supplementary Note 5). In this example, the encoded character is “S”. b Experimentally designed and measured skyrmion bags encoding the six characters “SKYRME”. For each bag, the four enclosed skyrmion numbers are extracted and mapped to ASCII characters based on the encoding rule shown in panel a, and further detailed in Supplementary Note 5. All measurements were performed under real-world noise, demonstrating robust information retrieval under perturbations