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

Year: 2019

Authors: Crespi A., Pepe FV., Facchi P., Sciarrino F., Mataloni P., Nakazato H., Pascazio S., Osellame R.

Autors Affiliation: Politecn Milan, Dipartimento Fis, I-120133 Milan, Italy; CNR, Ist Foton & Nanotecnol, I-120133 Milan, Italy; INFN, Sez Bari, I-70126 Bari, Italy; Univ Bari, Dipartimento Fis, I-170126 Bari, Italy; Univ Bari, MECENAS, I-170126 Bari, Italy; Sapienza Univ Roma, Dipartimento Fis, I-00185 Rome, Italy; Waseda Univ, Dept Phys, Tokyo 1698555, Japan; CNR, INO, I-50125 Florence, Italy.

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.

Journal/Review: PHYSICAL REVIEW LETTERS

Volume: 122 (13)      Pages from: 130401-1  to: 130401-6

More Information: R. O. acknowledges financial support by the European Research Council (ERC) Advanced Grant CAPABLE (Grant Agreement No. 742745). P.F. and S.P. are partially supported by Instituto Nazionale di Fisica Nucleare (INFN) through the project “QUANTUM.” F. V. P. is supported by INFN through the project ” PICS.” P. F. is partially supported by the Italian National Group of Mathematical Physics (GNFM-INdAM).
KeyWords: Quantum decay, Zeno effect, Integrated photonics, Quantum optical analogies
DOI: 10.1103/PhysRevLett.122.130401

ImpactFactor: 8.385
Citations: 33
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