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Center for Nonlinear Studies |
Electronic structure calculations are an important branch of quantum chemistry and are a critical simulation performed for materials discovery of OLED materials. Compute resources, simulation time, and inaccuracy prevent wide scale adoption within the chemical industry and these problems originate from the poor scaling factor of these calculations. Quantum computers represent a potential opportunity, since theory predicts better scaling factors for performing these calculations, but significant challenges remain. Most NISQ hardware are limited in number and quality of their qubits and their entangling gates have insufficient fidelity. These problems prevent NISQ era quantum hardware from computing meaningful and accurate molecular energies even with noise robust algorithms such as the Variational Quantum Eigensolver (VQE). New theories such as the Qubit Coupled Cluster (QCC) method were developed to improve the simulation accuracy, by reducing the number of 2-qubit entanglement gates required to reach chemical accuracy compared to other theories such as the Unitary Coupled Cluster. In this seminar, we will discuss how the QCC theory came about, why it generates shallow quantum circuits, and the benefits of its systematic generation of qubit entanglers. We will also present the iterative application of the QCC theory and demonstrate its systematic convergence to the full CI solution.
Host: Pavel Dub