Physics Colloquium- Simulating Complex Dynamics with a Small, Highly Accurate Quantum Simulator

Dr. Poul Jessen Optical Sciences, University of Arizona

Abstract: Rudimentary quantum processors consisting of tens of qubits have been realized on several physical platforms, and it is hoped these noisy intermediate-scale quantum (NISQ) devices might be used for classically hard tasks such as analog quantum simulation. Even so, it remains unclear if a quantum processor without error correction can compute meaningful results in the presence of realistic device imperfections. To probe this question we have developed a universal, highly accurate analog quantum processor operating in the 16dimensional Hilbert space associated with the coupled electron-nuclear spins of individual Cs atoms in the electronic ground state. Advances in optimal control allows us to drive unitary transformations with very high fidelity (>99%), and thus to perform coarse-grained simulations of the time evolution of any quantum system that fits in the available Hilbert space. In particular, we have studied the simulation of model Hamiltonians that have common features of interest, such as chaos and hypersensitivity (the quantum kicked top), and quantum phase transitions (the Lipkin-Meshkov-Glick and transverse Ising models). Experimentally we demonstrate analog quantum simulation of these models with high fidelity at the quantum state level, and with robust tracking of global observables such as magnetization. With a solid understanding of the inherent device performance, our next step will be to deliberately introduce non-native errors and study how they impact the accuracy of simulation.


** Refreshments served from 2:45pm – 3:00pm in PAS 218.  Thank you. **


3 p.m. to 4 p.m. April 19, 2019


PAS 224