2015/12/31 by M. Naghiloo, Mahdi Naghiloo, N. Foroozani +5 · 1 citation
Computer Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Cold Atom Physics and Bose-Einstein Condensates #Common emitter #Direct-conversion receiver #Homodyne detection #Laser #Open quantum system #Optoelectronics #Photodetection #Photodetector #Physics #Quantum #Quantum Information and Cryptography #Quantum mechanics #Quantum optics #Quantum sensor #Quantum state #Quantum technology #Quantum tomography #Spontaneous emission #cond-mat.mes-hall #physics.atom-ph #quant-ph
paper · pdf · doi:10.1038/ncomms11527
published as Nature Communications 7, Article number: 11527 (2016) · 8 pages, 8 figures
arxiv created 2016/03/24 · openalex publication_date 2016/05/11 · arxiv updated 2017/03/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The evolution of a quantum state undergoing radiative decay depends on how its emission is detected. If the emission is detected in the form of energy quanta, the evolution is characterized by a quantum jump to a lower energy state. In contrast, detection of the wave nature of the emitted radiation leads to different dynamics. Here, we investigate the diffusive dynamics of a superconducting artificial atom under continuous homodyne detection of its spontaneous emission. Using quantum state tomography, we characterize the correlation between the detected homodyne signal and the emitter's state, and map out the conditional back-action of homodyne measurement. By tracking the diffusive quantum trajectories of the state as it decays, we characterize selective stochastic excitation induced by the choice of measurement basis. Our results demonstrate dramatic differences from the quantum jump evolution associated with photodetection and highlight how continuous field detection can be harnessed to control quantum evolution.