Quantum probes for many-body systems

Abstract

The key ingredient for understanding many-body systems when performing quantum simulations is an efficient readout of the available information. In quantum systems every extraction of information implies a backaction altering the system’s state. Here, we present the first steps towards new quantum-limited probes for many-body quantum systems. For our experimental studies we use one-dimensional Bose-Einstein condensates on an atomchip combined with spatially resolved measurements. To probe the system, we employ global as well as local fields for outcoupling a controllable number of atoms which we detect with near unit efficiency. The controlled outcoupling allows us to tune the strength of the perturbation and we thus can study the influence of the measurement backaction. We further present a new approach to Hamiltonian learning for many-body systems. Translating the recently developed methods for discrete systems to the framework of quantum fields, we aim to study the scale dependence of the emerging physics. We present first results in the regime of a quadratic Hamiltonian and give an outlook on the possibilities for more complex situations.