Effects of gate errors in digital quantum simulations of fermionic systems

Speaker: 
Prof. Gerd Schön
From: 
Karlsruhe Institute of Technology, Germany
When: 
3pm Thursday 13th September 2018
Where: 
Room G59, Old Main Building, UNSW Kensington Campus

Digital quantum simulations offer exciting perspectives for the study of fermionic systems such as molecules or lattice models. However, with quantum error correction still being out of reach with present-day technology, a non-vanishing error rate is inevitable. We study the influence of gate errors on simulations of the Trotterized time evolution of the quantum system. Specifically we consider the effect of stochastic over-rotations in the applied gates with focus on the fermionic Hubbard model. Depending on the particular algorithm implemented such gate errors lead to a time evolution that corresponds to a disordered fermionic system. For different algorithms the errors may correspond to unphysical errors, e.g., violate particle number conservation. In addition we establish the relation between the gate fidelity and the strength of the over-rotations in a Trotterized quantum simulation and thus of the equivalent disorder strength. We substantiate our analysis by numerical simulations of model systems.
The talk is based on the paper
J.-M. Reiner, S. Zanker, I. Schwenk, J. Leppäkangas, F. Wilhelm-Mauch, G. Schön, and M. Marthaler, Quantum Science and Technology 3, 045008 (2018)