Measurement-Induced Strong Kerr Nonlinearity for Weak Quantum States of Light
Authors: Costanzo L. S., Coelho A. S., Biagi N., Fiurášek J., Bellini M., Zavatta A.
Autors Affiliation: Istituto Nazionale di Ottica (INO-CNR), Largo E. Fermi 6, 50125 Florence, Italy: LENS and Department of Physics, University of Firenze, 50019 Sesto Fiorentino, Florence, Italy; Departamento de Engenharia Mecânica, Universidade Federal do Piauí, 64049-550 Teresina, Piauí, Brazil; Department of Optics, Palacký University, 17. listopadu 1192/12, CZ-771 46 Olomouc, Czech Republic
Abstract: Strong nonlinearity at the single photon level represents a crucial enabling tool for optical quantum technologies. Here we report on experimental implementation of a strong Kerr nonlinearity by measurement-induced quantum operations on weak quantum states of light. Our scheme coherently combines two sequences of single photon addition and subtraction to induce a nonlinear phase shift at the single photon level. We probe the induced nonlinearity with weak coherent states and characterize the output non-Gaussian states with quantum state tomography. The strong nonlinearity is clearly witnessed as a change of sign of specific off-diagonal density matrix elements in the Fock basis.
Journal/Review: PHYSICAL REVIEW LETTERS
Volume: 119 (1) Pages from: 013601-1 to: 013601-6
KeyWords: Optical Kerr effect; Particle beams; Phase shift; Photons; Quantum optics, Density matrix elements; Nonlinear phase shift; Quantum operations; Quantum state tomography; Quantum technologies; Single-photon level; Strong nonlinearity; Weak coherent state, Quantum theoryDOI: 10.1103/PhysRevLett.119.013601