Speaker: Lucas Ribeiro
Affiliation: Federal University of São Carlos - UFSCar
Date: Tuesday, 12 May 2026 at 12:00
Location: Seminar Room, Serrano 113b
Large Fock states are key nonclassical resources for bosonic quantum information, quantum-enhanced metrology, and the exploration of nonclassical dynamics in harmonic oscillators. However, preparing them high success probability remains challenging: deterministic protocols become increasingly control-intensive at large excitation number, while measurement-based strategies are naturally robust but suffer from rapidly decreasing probabilities. In this work, we propose a dispersive circuit-QED protocol that combines Quantum Phase Estimation (QPE) and Quantum Amplitude Amplification (QAA) to overcome this limitation. Starting from a coherent state in a bosonic resonator, QPE maps photon-number information onto a multi-qubit register through photon-number dependent dispersive phases, while QAA coherently amplifies the target register outcome before measurement. In this way, the protocol transforms a weakly heralded measurement scheme into a high-probability preparation method for large Fock states. The approach is compatible with standard superconducting architectures, requires only logarithmic qubit overhead, and exhibits favorable scaling of the amplification cost.