Freiburg 2019 – wissenschaftliches Programm

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FM: Fall Meeting

FM 75: Quantum Computation: Simulation II

FM 75.1: Talk

Donnerstag, 26. September 2019, 14:00–14:15, 1010

Finding symmetry-broken ground states with variational quantum algorithms — •Nicolas Vogt¹, Sebastian Zanker¹, Jan-Michael Reiner¹, Thomas Eckl², Anika Marusczyk², and Michael Marthaler¹ — ¹HQS Quantum Simulations GmbH, Karlsruhe, Germany — ²Robert Bosch GmbH, Renningen, Germany

One of the most promising applications for near-term noisy intermediate scale quantum computers (NISQ) is the preparation of the fully interacting ground state of strongly correlated electron systems. Besides the true ground state energy the properties of interest are, e.g., phases with broken symmetry and the corresponding order parameters.

We study the preparation of ground states with broken symmetry on a gate based quantum computer with different variational algorithms, specifically the variational Hamiltonian ansatz (VHA) including initial state preparation and extensions to deal with broken symmetry. The Hubbard model, which is known for its variety of phases, is used as a toy model to compare the different variational algorithms to each other and to exact diagonalisation. To this end, we simulate the full algorithm including initialisation and read-out running on a gate-based quantum computer. We use a hardware model based on the gates available in current generation superconducting quantum computers.