Realizing and probing quantum fields with ultra-cold atoms

Quantum field theories (QFTs) are among the most fundamental descriptions of physical systems. A prominent example is the Standard Model which describes the dynamics and interactions of elementary particles, out of which all matter around us is made, through the language of fluctuating (quantum) fields. But the applicability of QFTs is much broader, spanning an enormous range of energies from the dynamics shortly after the Big-Bang down to the coldest places in the universe, so called Bose-Einstein condensates which nowadays can be efficiently created, manipulated, and measured in laboratories. Despite its successes QFTs are notoriously hard to calculate, in most cases precluding an exact solution of the problem even on classical supercomputers. At the Atominstitut of the TU Vienna we will experimentally study QFTs by using Analogue Quantum Simulators. By cooling around 5000 rubidium atoms down to temperatures only a billionth of a fraction above absolute zero they enter a new phase of matter: a so called Bose- Einstein condensate (BEC), where the atoms behave as a collective macroscopic quantum object. Similar to describing the dynamics of water not as the movement of individual atoms but through waves in fluid dynamics, the BEC can be described in the language of QFTs. Combining the stability of the AtomChips pioneered by Jörg Schmiedmayer with additional optical control via a digital micromirror device allows us to design model QFTs in the lab. The high degree of experimental control over the system and measurement enables us to study in detail their dynamics, interactions and response to controlled perturbations. In particular, we will study the Sine-Gordon model, which is an interacting QFT that appears as an effective description in a variety of quantum many-body systems. With complementary theoretical developments by our Hungarian partners, we aim to establish analogue quantum simulators for precision studies of non-equilibrium quantum field theory.