Experimental Investigation of Quantum Decay at Short, Intermediate, and Long Times via Integrated Photonics

Andrea Crespi, Francesco V. Pepe, Paolo Facchi, Fabio Sciarrino, Paolo Mataloni, Hiromichi Nakazato, Saverio Pascazio, Roberto Osellame*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


The decay of an unstable system is usually described by an exponential law. Quantum mechanics predicts strong deviations of the survival probability from the exponential: Indeed, the decay is initially quadratic, while at very large times it follows a power law, with superimposed oscillations. The latter regime is particularly elusive and difficult to observe. Here we employ arrays of single-mode optical waveguides, fabricated by femtosecond laser direct inscription, to implement quantum systems where a discrete state is coupled and can decay into a continuum. The optical modes correspond to distinct quantum states of the photon, and the temporal evolution of the quantum system is mapped into the spatial propagation coordinate. By injecting coherent light states in the fabricated photonic structures and by measuring a small scattered fraction of such light with an unprecedented dynamic range, we are able to experimentally observe not only the exponential decay regime, but also the quadratic Zeno region and the power-law decay at long evolution times.

Original languageEnglish
Article number130401
JournalPhysical Review Letters
Issue number13
Publication statusPublished - 2019 Apr 3

ASJC Scopus subject areas

  • Physics and Astronomy(all)


Dive into the research topics of 'Experimental Investigation of Quantum Decay at Short, Intermediate, and Long Times via Integrated Photonics'. Together they form a unique fingerprint.

Cite this