Quantum Information Processing with Light: from Single Photons to Continuous Variables

In this talk, I will present my journey moving from working with single photons to continuous variables. The signal-to-noise ratio (SNR) of range measurements can be improved by quantum detection and quantum light sources (quantum ranging). In the first part, I will present the theory of quantum ranging in the framework of Gaussian states. I will show that an optimal detection strategy, which minimizes the detection errors, can be applied for an arbitrary return state from the target. Then I will discuss the use of quantum light in the same scenario. Optimal detection is important in high-loss mediums, such as underwater, where low signal returns and maximizing its information is needed. In the second part, I will present experimental results of improved sensitivity of a temperature sensor and quantum simulations with single photons and will present my plans to extend the theory and experiments to Gaussian states. I will show simulations of a basic transition of quantum gravity theory and discuss scaling it up to complex transitions. Complex versions of these simulations have the potential to advance the research of basic science.