Quantum simulation of spin models with tunable atom arrays

• Applicant: Dr. Ahmed Omran
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2016 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 328801971

This project aims at realising a simulator for quantum spin models using cold atoms. The protocol involves laser cooling of rubidium atoms and loading of many optical microtraps in parallel with single atoms. Fluorescence imaging of the atoms allows for detecting empty traps and removing defects by extinguishing these traps. The populated traps are then rearranged to produce a regular array of atoms without defects. This protocol provides a high degree of reproducibility of the experiments and can be performed with high repetition rates of up to 10 experimental runs per second.The atoms localised in the traps serve as individual spins. The spin degree of freedom is encoded in the internal energy state of the outermost electron of each atom, e.g. the hyperfine state of the electron.Quantum spin models rely on the interaction between different spins. As no long-range interactions exist between distant rubidium atoms in their ground state, these interactions need to be introduced by promoting the outermost electron of the atoms to highly excited Rydberg levels. This enables strong van-der-Waals interactions over long distances of several microns. Rydberg excitations in many-body systems allow for observing collective dynamics, entanglement and realising quantum information protocols, as well as engineering the many-body interactions necessary for simulating spin models.Another long term goal is to interface the atom arrays with photonic crystal waveguide cavities, where the atoms are strongly coupled to the photons in the cavity mode. The deterministic preparation of atomic qubit arrays coupled via cavity modes allows for developing robust and scalable quantum networks.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professor Mikhail Lukin