Simulation of open quantum systems with giant atoms

Open quantum many-body systems are both of fundamental interest and have practical applications. In many cases, numerically solving such systems with classical methods is infeasible; instead, quantum simulation is required. Yet, conventional quantum simulation methods either require a large amount of ancilla qubits or operate within limited parameter spaces. To overcome these challenges, we put forward a novel protocol for simulating open quantum many-body systems with giant atoms. Unlike conventional point-like small atoms, giant atoms couple to the environment at multiple points, yielding interference effects that grant remarkable tunability in the interactions between the atoms and the environment. Utilizing this high tunability, we demonstrate efficient simulation of a variety of open quantum systems with two giant atoms coupled to a waveguide. We further show the capability of this setup to simulate models not intrinsically present in the system by tuning the qubit frequencies at different time steps. Our results can be extended to a larger number of giant atoms, and pave the way towards versatile simulation of open quantum many-body systems.