Simulations of two particle dynamics employing dynamic coin control in 2D quantum walks

Summary form only given. There has been constantly rising interest in quantum walks in recent years, as they are a well-snited framework to study quantum algorithms, for example [1, 2] or to use them as a simulator for other quantum systems, which are not as readily accessible [3]. A key element for a versatile simulator is the ability to dynamically control the quantum-coin, which is the main entity responsible for the evolution of the quantum walk.Here we demonstrate the simulation of interacting bosonic particles by using a photonic realization of a 2D discrete-time quantum walk, as introduced in [3]. We investigate different interaction types making use of the direct dynamic access to the internal coin state of the walker in our setup and realize either a bunching or anti-bunching behavior of the particles, as shown in figure 1. The utilization of the polarization state as coin state allows for easy manipulation by simply introducing controlled phase shifts through an electro optic modulator to selectively modify the coin state. This enables us to tune interaction strengths and patterns to engineer simulations of different kinds of particles or environments and thus enhancing the abilities of photonic experiments to include controlled interactions.