Friday, May 21, 2021 - 10:30am to 12:30pm

Title: Quantum Simulations of Many-body Effects in Isoelectronic Systems.

Abstract: The emerging field of quantum simulation of many-body systems is widely recognized as a very important application of quantum computing. A crucial step towards its realization in the context of many-electron systems requires a rigorous quantum mechanical treatment of the different interactions. We investigate the physical effects beyond the mean-field approximation, known as electron correlation, in the ground state energies of atomic systems using the classical-quantum hybrid variational quantum eigensolver (VQE) algorithm. To this end, we consider three isoelectronic species which span three classes, a neutral atom, an anion, and a cation. We employed the unitary coupled-cluster (UCC) ansatz to perform a rigorous analysis of two very important factors that could affect the precision of the simulations of electron correlation effects within a basis, namely mapping and backend simulator. We carry out our calculations with four such basis sets. The results obtained are compared with those calculated by using the full configuration interaction, traditional coupled-cluster, and the UCC methods, on a classical computer, to assess the precision of our results. A salient feature of the study involves a detailed analysis to find the number of shots (the number of times a VQE algorithm is repeated to build statistics) required for calculations with IBM Qiskit's QASM simulator backend, which mimics an ideal quantum computer.

Biography: Sumeet K isworking as an intern at Qu & Co, Amsterdam, The Netherlands in the application of quantum computation to quantum chemistry. This specifically includes tackling the electronic-structure problem on the quantum computer/simulator.