### Abstract

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 language | English |
---|---|

Article number | 130401 |

Journal | Physical Review Letters |

Volume | 122 |

Issue number | 13 |

DOIs | |

Publication status | Published - 2019 Apr 3 |

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### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*Physical Review Letters*,

*122*(13), [130401]. https://doi.org/10.1103/PhysRevLett.122.130401

**Experimental Investigation of Quantum Decay at Short, Intermediate, and Long Times via Integrated Photonics.** / Crespi, Andrea; Pepe, Francesco V.; Facchi, Paolo; Sciarrino, Fabio; Mataloni, Paolo; Nakazato, Hiromichi; Pascazio, Saverio; Osellame, Roberto.

Research output: Contribution to journal › Article

*Physical Review Letters*, vol. 122, no. 13, 130401. https://doi.org/10.1103/PhysRevLett.122.130401

}

TY - JOUR

T1 - Experimental Investigation of Quantum Decay at Short, Intermediate, and Long Times via Integrated Photonics

AU - Crespi, Andrea

AU - Pepe, Francesco V.

AU - Facchi, Paolo

AU - Sciarrino, Fabio

AU - Mataloni, Paolo

AU - Nakazato, Hiromichi

AU - Pascazio, Saverio

AU - Osellame, Roberto

PY - 2019/4/3

Y1 - 2019/4/3

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85064041802&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85064041802&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.122.130401

DO - 10.1103/PhysRevLett.122.130401

M3 - Article

C2 - 31012619

AN - SCOPUS:85064041802

VL - 122

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 13

M1 - 130401

ER -