Single-shot parity readout of a minimal Kitaev chain.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41673287.
- Also identified by DOI 10.1038/s41586-025-09927-7.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Protecting qubits from noise is essential for building reliable quantum computers. Topological qubits offer a route to this goal by encoding quantum information non-locally, using pairs of Majorana zero modes. These modes form a shared fermionic state whose occupation-either even or odd-defines the fermionic parity that encodes the qubit<sup>1</sup>. Notably, this parity can only be accessed by a measurement that couples two Majoranas to each other. A promising platform for realizing such qubits is the Kitaev chain<sup>1</sup>, implemented in quantum dots coupled using superconductors<sup>2</sup>. Even the minimal two-site chain hosts a pair of Majorana modes, often called 'poor man's Majoranas', which are spatially separated but offer limited protection compared with longer chains<sup>3-5</sup>. Here we introduce a measurement technique that reads out their parity through quantum capacitance. Our method couples two Majoranas and resolves their parity in real time, visible as random telegraph switching with lifetimes exceeding a millisecond. Simultaneous charge sensing confirms that the two parity states are charge neutral and remain indistinguishable to a probe that does not couple the modes. These results establish the essential readout step for time-domain control of Majorana qubits, resolving a long-standing experimental challenge.