Fluctuations in Atomtronic Circuits

ended

Ultracold quantum gases provide a unique highly-controllable platform to test fundamental aspects of quantum mechanics and to engineer novel quantum technologies and sensing devices. Recently, an emerging subfield called “atomtronics” is attracting increasing interest. Atomtronics aims to study neutral atomic circuits in optical and magnetic traps, in a manner analogous, but complementary, to electronic circuits. This proposal focusses on two key aspects in such systems, namely on modelling the dynamics in ring-trap geometries – which benefit from the topological protection of (neutral) atomic currents – and characterizing the dynamical emergence and transfer of coherence in analogue neutral-atomic transistors. The novel feature of this project is the inclusion of experimentally-relevant fluctuations via appropriate state-of-the-art modelling schemes (namely the stochastic Gross-Pitaevskii and the Zaremba-Nikuni-Griffin model) which fully include coupling of coherent and incoherent modes and associated fluctuations, made possible through high-performance computing simulations. The specific end-goal is to provide an in-depth characterisation of the dynamics of coherence in such circuits, thus both addressing open questions in the literature and identifying from the theoretical perspective the optimal specifications and parameter regimes which experimentalists could use to create an advanced atomic sensing device (atomic analogue of the superconducting quantum-interference device) and an atomic ring-based transistor. The proposed research has strong connections with existing experimental implementations, including the existing/planned setups at FORTH (Crete) [von Klitzing's group] and LKB (Paris) [Beugnon/Dalibard group], where the applicant will perform targeted secondments with the aim of becoming more familiar with experimental issues and devising potential strategies, thus contributing to potential future implementations of such devices.