Regensburg 2022 – wissenschaftliches Programm
QI 12.2: Vortrag
Donnerstag, 8. September 2022, 15:15–15:30, H8
Calculation of Correlated Electronic States on Noisy Intermediate Scale Quantum Computers — •Jannis Ehrlich1, Daniel Urban1, and Christian Elsässer1,2 — 1Fraunhofer-Institut für Werkstoffmechanik IWM, Freiburg, Germany — 2Freiburger Materialforschungszentrum, Universität Freiburg, Germany
The numerical description of correlated electrons on conventional computers is limited to small system sizes. For the exact diagonalization approach, for example, all configurations in the many-particle space have to be considered, and their number grows exponentially with the number of one-particle states. This limitation can be overcome by simulating the correlated electrons with one of the artificial quantum systems that recently became available through the advance in quantum computing technologies. On such systems, each one-particle state can be represented by one qubit, which can be entangled with each other to generate superpositions. Thus, a linear scaling in the number of qubits is sufficient to cover the full many-particle space. Here, we describe strongly correlated systems within the dynamical mean-field theory (DMFT) and investigate its possible realization on a quantum computer. As a proof of concept, we study the simplified version of two-site DMFT both, by using simulators and an IBMQ quantum computer. We show that a solution of this model can be obtained using the quantum-classical variational quantum eigensolver (VQE). As the quality of the results is limited by the noise level of current quantum computers (NISQ type), we further investigate how different error mitigation strategies can improve the results.