January 12, 2021

Quantum linear and nonlinear interferometers. The interaction of quantum light with atomic systems.

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Speaker: Polina R. Sharapova (Univ. of Paderborn, Germany)

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Abstract:

Quantum interference is a powerful apparatus in modern quantum optics that can be used for precise time and phase measurements, generating entanglement and testifying a non-locality of entangled systems. At the same time, the multiphoton interference is an essential ingredient for machine learning, quantum neural networks and boson sampling, which are the first steps of future quantum computing.

Nonlinear interferometry gives a new insight into quantum interference. A non- linear (SU(1,1)) interferometer can be obtained from conventional linear interferometer by replacing the beam splitters with nonlinear media. Such class of interferometers indicates stability to the external losses and simultaneously shows an improvement in the phase sensitivity compared to their linear counterparts. Nonlinear interferometers are useful tools for creating single-mode sources and providing spectral engineering of light with different intensity profiles and mode contents. The interaction of matter with quantum light generated in parametric down-conversion process and nonlinear interferometers based on it leads to new phenomena which cannot be explained by semiclassical approaches.

Taking into account the state-of-the-art of rapidly developing integrated technologies, which provide higher efficiencies and smaller footprints, quantum linear and nonlinear interferometers can be realised in integrated platforms.

This talk will highlight our recent advances in quantum linear and nonlinear interferometers, their integrated implementations, generation of multidimensional entangled states in extended interferometers, generation of bright squeezed states of light with a huge number of photons and strong correlations in nonlinear interferometers, as well as in the interaction of matter with specific quantum states of light and new phenomena arising within such interaction.