The understanding of weak measurements and interaction-free measurements has greatly expanded the conceptual and experimental toolbox to explore the quantum world. Here we demonstrate single-shot variable-strength weak measurements of the electron and the nuclear spin states of a single 31P donor in silicon. We first show how the partial collapse of the nuclear spin due to measurement can be used to coherently rotate the spin to a desired pure state. We explicitly demonstrate that phase coherence is preserved throughout multiple sequential single-shot weak measurements, and that the partial state collapse can be reversed. Second, we use the relation between measurement strength and perturbation of the nuclear state as a physical meter to extract the tunneling rates between the 31P donor and a nearby electron reservoir from data, conditioned on observing no tunneling events. Our experiments open avenues to measurement-based state preparation, steering and feedback protocols for spin systems in the solid state, and highlight the fundamental connection between information gain and state modification in quantum mechanics.
The 2023 Boyer Lecture series is called 'The Atomic Revolution' and is presented by Professor Michelle Simmons AO, a pioneer in atomic electronics and global leader in quantum computing.READ
CQC2T Director Professor Michelle Simmons AO and Chief Investigator Professor Yuerui (Larry) Lui were recognised in the prestigious 2023 Prime Minister’s award ceremony held at Parliament House last nREAD
An international team of researchers has developed a technology that has shattered a world record in continuous variable quantum teleportation. This latest technology offers a viable pathway enroute tREAD
Fault-tolerant, error-corrected quantum computation is commonly acknowledged to be crucial to the realisation of large-scale quantum algorithms that could lead to extremely impactful scientific or comREAD
Engineers show that a jellybean-shaped quantum dot creates more breathing space in a microchip packed with qubits.READ