Neutral Rydberg atoms in optical lattices or optical tweezer arrays are a fascinating scalable physical platform to realise quantum information processing and explore strongly correlated many-body quantum physics. Here, atoms can be laser-excited to high-lying electronic so-called Rydberg states, in which they exhibit strong and long-range interactions. These can be then be used in a controllable fashion for the realisation of ultra-fast two- or even multi-qubit gate operations, to build e.g. digital quantum computers and simulators [1,2].
Moreover, our group developed, in cooporation with the Wille Group (TUM) and the Marquardt group (MPI Erlangen), tools for optimization of encoding quantum circuits [3] and translation of quantum circuits into quantum platform specific native gates [5]. Beyond this, our group developed a novel variational ansatz to prepare the ground state of a Z2 lattice gauge theory using dissipative as well as unitary elements [6] which provably outperforms the conventional only-unitary ansatz. Another research direction is the development of new codes. In this regard, we developed a new family of codes based on the recently introduced lifted product, the lift-connected surface codes [4], which show promising performance at already moderate number of physical qubits and therefore have an edge over other conventional codes.
The aim of the MUNIQC-Atoms collaboration, which involves academic as well as industrial partners and is part of the Munich Quantum Valley initiative, is the development and implementation of neutral-atom based quantum processors with up to 400 qubits. In our Theoretical Quantum Technology group, we will on the one hand focus on developing new schemes for fault-tolerant error correction, which are tailormade for the platforms developed by our experimental partners. These protocols will thereby directly support the first realisation of robust and error-corrected logical qubits in neutral-atom quantum processors. On the other hand, we will develop novel error correction strategies and efficient decoders, realise theory studies and propose new schemes for scalable fault-tolerant Rydberg atom quantum computing, and explore novel many-body physics phenomena in this emergent quantum technology platform.
[1] Mesoscopic Rydberg Gate based on Electromagnetically Induced Transparency, M. Müller, I. Lesanovsky, H. Weimer, H. Büchler, P. Zoller, Phys. Rev. Lett. 102, 170502 (2009).
[2] A Rydberg Quantum Simulator, H. Weimer, M. Müller, I. Lesanovsky, P. Zoller, H.-P. Büchler, Nature Phys. 6, 382 (2010).
[3] Quantum Circuit Discovery for Fault-Tolerant Logical State Preparation with Reinforcement Learning, R. Zen, J. Olle, L. Colmenarez, M. Puviani, M. Müller, and F. Marquardt, arXiv:2402.17761 (2024).
[4] Lift-Connected Surface Codes, J. Old, M. Rispler, and M. Müller, Quantum Sci. Technol. 9 045012 (2024).
[5] Compiler Optimization for Quantum Computing Using Reinforcement Learning, N. Quetschlich, L. Burgholzer, and R. Wille, arXiv:2212.04508 (2022).
[6] Noise-Aware Variational Eigensolvers: A Dissipative Route for Lattice Gauge Theories, J. Cobos, D. F. Locher, A. Bermudez, M. Müller, and E. Rico, PRX Quantum 5, 030340 (2023).
Illustration Credit: MPQ