Markus OBERTHALER
Ultracold gases offer an experimental platform with pristine control of parameters as well as unique readout capabilities offering access to new observables. In this talk I will present two experimental implementations of a quantum field simulator. With the use of a Rubidium spinor condensates we investigate the question about the emergence of universal time dynamics. I will present our latest results revealing the existence of two distinct non-thermal fixed points in the same Hamiltonian system. We find the corresponding universal functions and exponents characterizing the underlying structures.
With the platform of a two-dimensional ultracold potassium gas we implement an action describing a free relativistic scalar field in the quantum limit with full control in space and time of the underlying metric. We demonstrate quantum wave packet dynamics in hyperbolic and spherical spatial geometry clearly revealing the curvature. Extending the concept of curvature to time we confirm the expected particle production. Building on the unique readout capabilities we can not only access the number of generated particles but also for the first time the phase of the excitation amplitudes. The quantitative agreement with new analytical predictions for time dependent metrics benchmarks the simulator and with that establishes the new class of quantum field simulators implementing relativistic quantum actions.