Teague Tomesh will present his General Exam, "Minimizing State Preparations in Variational Quantum Eigensolver by Partitioning into Commuting Families" on Friday, January 17, 2020 at 1:30pm in CS 402. The members of his committee are as follows: Margaret Martonosi (adviser), Steve Lyon (EE), and Fred Chong (University of Chicago - Computer Science). Everyone is invited to attend his talk, and those faculty wishing to remain for the oral exam following are welcome to do so. His abstract and reading list follow below. Variational quantum eigensolver (VQE) is a promising algorithm suitable for near-term quantum computers. VQE aims to approximate solutions to exponentially-sized optimization problems by executing a polynomial number of quantum subproblems. However, the number of subproblems scales as N^4 for typical problems of interest — a daunting growth rate that poses a serious limitation for emerging applications such as quantum computational chemistry. We mitigate this issue by exploiting the simultaneous measurability of subproblems corresponding to commuting terms. Our technique transpiles VQE instances into a format optimized for simultaneous measurement, yielding a linear-factor asymptotic improvement that translates to 8-30x lower cost for near term benchmarks. Our work also encompasses a synthesis tool for compiling simultaneous measurement circuits with minimal overhead. We demonstrate experimental validation of our techniques by estimating the ground state energy of deuteron with an IBM quantum computer. We also investigate the underlying statistics of simultaneous measurement and devise an adaptive strategy for mitigating harmful covariance terms. Textbook: Michael A Nielsen and Isaac L Chuang. Quantum computation and quantum information (10th anniv. version), 2010. Papers: 1. Richard Feynman. Simulating physics with computers. International Journal of Theoretical Physics, Vol 21, Now. 6/7, 1982 2. DiVincenzo, David P. "The physical implementation of quantum computation." Fortschritte der Physik: Progress of Physics/ 48, no. 9‐11 (2000): 771-783. 3. Peruzzo, Alberto, Jarrod McClean, Peter Shadbolt, Man-Hong Yung, Xiao-Qi Zhou, Peter J. Love, Alán Aspuru-Guzik, and Jeremy L. O’brien. "A variational eigenvalue solver on a photonic quantum processor." Nature communications 5 (2014): 4213. 4. Prakash Murali, Norbert Matthias Linke, Margaret Martonosi, Ali Javadi Abhari, Nhung Hong Nguyen, and Cinthia Huerta Alderete. 2019. Full-stack, real-system quantum computer studies: architectural comparisons and design insights. In Proceedings of the 46th International Symposium on Computer Architecture (ISCA '19). ACM, New York, NY, USA, 527-540. DOI: https://doi.org/10.1145/3307650.3322273 5. Preskill, John. "Quantum Computing in the NISQ era and beyond." Quantum 2 (2018): 79. 6. Tranter, Andrew, Peter J. Love, Florian Mintert, and Peter V. Coveney. "A Comparison of the Bravyi–Kitaev and Jordan–Wigner Transformations for the Quantum Simulation of Quantum Chemistry." Journal of chemical theory and computation 14, no. 11 (2018): 5617-5630. 7. X. Fu, M. A. Rol, C. C. Bultink, J. van Someren, N. Khammassi, I. Ashraf, R. F. L. Vermeulen, J. C. de Sterke, W. J. Vlothuizen, R. N. Schouten, C. G. Almudever, L. DiCarlo, and K. Bertels. 2017. An experimental microarchitecture for a superconducting quantum processor. In Proceedings of the 50th Annual IEEE/ACM International Symposium on Microarchitecture (MICRO-50 '17). ACM, New York, NY, USA, 813-825. DOI: https://doi.org/10.1145/3123939.3123952 8. Ravi Boppana and Magnús M Halldórsson. Approximating maximum independent sets by excluding subgraphs. BIT Numerical Mathematics, 32(2):180–196, 1992. 9. Jarrod R McClean,Jonathan Romero, Ryan Babbush, and Alán Aspuru-Guzik. The theory of variational hybrid quantum-classical algorithms. New Journal of Physics, 18(2):023023, 2016.