By employing a fully controlled cavity quantum electrodynamic system made of superconducting circuits, we experimentally create matrix product states, a class of states that has proven to be extremely powerful as a variational ansatz for numerical simulations. We create 1000 such quantum states and efficiently probe their correlation properties to determine an approximation to the ground state of a model describing a gas of interacting quantum particles. Having physical access to the simulated ground-state wave functions enables us to also probe higher-order correlation functions beyond measuring the ground-state energy. The experimental data are in good agreement with the exact solution over a wide range of interaction strengths of the model.
Quantum simulations are expected to vastly outperform classical simulations when modeling the dynamics of interacting spin systems. Researchers have used a digital quantum simulation to show that spin dynamics can be studied and predicted, which lays the groundwork for applications in quantum magnetism and strongly correlated systems.
We realized a two-spin "Gedankenexperiment" suggested by Dicke in 1954 using a system of two individually controllable superconducting qubits weakly coupled to a fast decaying microwave cavity. We demonstrate superradiance of two emitters both in time and by reconstructing the density matrix of the emitted field. The results of this work are published in Nature Communications.
We have implemented a scheme for generating single microwave photons with a tunable shape in superconducting circuits. The experiment describing the fully microwave-controlled shaping process is published in Phys. Rev. X .
ETH President Ralph Eichler's final Lokaltermin event focused on a topic close to his heart: together with five other experts from ETH Zurich, he gave representatives from the worlds of business, politics and science an insight into the unusual world of quantum physics and explained how it may be used commercially in the future.