2026/03/08 by Aritra Sen, András Pályi
Computer Science · Physics and Astronomy · #Noise (video) #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum gate #Qubit #Reflectometry #Spin (aerodynamics)
paper · pdf · doi:10.1103/737j-gmns
published in Physical review. B./Physical review. B 113(23) (American Physical Society)
openalex publication_date 2026/05/26 · openalex created_date 2026/05/27 · openalex updated_date 2026/08/05
Single-electron spin qubits defined in quantum dots are used as building blocks of a semiconductor-based quantum computer. Readout in a scaled-up version of such a quantum computer is expected to rely on the Pauli Spin Blockade (PSB) mechanism. A desired functionality of PSB readout is that it reveals two bits of information on the two spin qubits that are involved in the process, such that the four computational basis states can be discriminated. In this work, we propose and quantitatively analyze an experimental procedure, based on gate reflectometry, which enables this four-state discrimination in a single measurement. We provide an intuitive recipe to maximize the contrast between the quantum capacitances of the four basis states. Focusing on silicon double quantum dots equipped with a micromagnet, we quantify how amplifier noise and phonon-mediated relaxation influence readout fidelity. Our results highlight a realistic opportunity to mitigate the overhead of readout ancilla qubits in a spin-based quantum computer.