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arXiv · 2004.04174

Hartree-Fock on a superconducting qubit quantum computer

Frank Arute·Kunal Arya·Ryan Babbush·Dave Bacon·Joseph C. Bardin·Rami Barends·Sergio Boixo·Michael Broughton·Bob B. Buckley·David A. Buell·Brian Burkett·Nicholas Bushnell·Yu Chen·Zijun Chen·Benjamin Chiaro·Roberto Collins·William Courtney·Sean Demura·Andrew Dunsworth·Daniel Eppens·Edward Farhi·Austin Fowler·Brooks Foxen·Craig Gidney·Marissa Giustina·Rob Graff·Steve Habegger·Matthew P. Harrigan·Alan Ho·Sabrina Hong·Trent Huang·William J. Huggins·Lev Ioffe·Sergei V. Isakov·Evan Jeffrey·Zhang Jiang·Cody Jones·Dvir Kafri·Kostyantyn Kechedzhi·Julian Kelly·Seon Kim·Paul V. Klimov·Alexander Korotkov·Fedor Kostritsa·David Landhuis·Pavel Laptev·Mike Lindmark·Erik Lucero·Orion Martin·John M. Martinis·Jarrod R. McClean·Matt McEwen·Anthony Megrant·Xiao Mi·Masoud Mohseni·Wojciech Mruczkiewicz·Josh Mutus·Ofer Naaman·Matthew Neeley·Charles Neill·Hartmut Neven·Murphy Yuezhen Niu·Thomas E. O'Brien·Eric Ostby·Andre Petukhov·Harald Putterman·Chris Quintana·Pedram Roushan·Nicholas C. Rubin·Daniel Sank·Kevin J. Satzinger·Vadim Smelyanskiy·Doug Strain·Kevin J. Sung·Marco Szalay·Tyler Y. Takeshita·Amit Vainsencher·Theodore White·Nathan Wiebe·Z. Jamie Yao·Ping Yeh·Adam Zalcman
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Abstract

As the search continues for useful applications of noisy intermediate scale quantum devices, variational simulations of fermionic systems remain one of the most promising directions. Here, we perform a series of quantum simulations of chemistry the largest of which involved a dozen qubits, 78 two-qubit gates, and 114 one-qubit gates. We model the binding energy of ${\rm H}_6$, ${\rm H}_8$, ${\rm H}_{10}$ and ${\rm H}_{12}$ chains as well as the isomerization of diazene. We also demonstrate error-mitigation strategies based on $N$-representability which dramatically improve the effective fidelity of our experiments. Our parameterized ansatz circuits realize the Givens rotation approach to non-interacting fermion evolution, which we variationally optimize to prepare the Hartree-Fock wavefunction. This ubiquitous algorithmic primitive corresponds to a rotation of the orbital basis and is required by many proposals for correlated simulations of molecules and Hubbard models. Because non-interacting fermion evolutions are classically tractable to simulate, yet still generate highly entangled states over the computational basis, we use these experiments to benchmark the performance of our hardware while establishing a foundation for scaling up more complex correlated quantum simulations of chemistry.

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Frank Arute, Kunal Arya, Ryan Babbush, Dave Bacon, Joseph C. Bardin, Rami Barends, Sergio Boixo, Michael Broughton, Bob B. Buckley, David A. Buell, Brian Burkett, Nicholas Bushnell, Yu Chen, Zijun Chen, Benjamin Chiaro, Roberto Collins, William Courtney, Sean Demura, Andrew Dunsworth, Daniel Eppens, Edward Farhi, Austin Fowler, Brooks Foxen, Craig Gidney, Marissa Giustina, Rob Graff, Steve Habegger, Matthew P. Harrigan, Alan Ho, Sabrina Hong, Trent Huang, William J. Huggins, Lev Ioffe, Sergei V. Isakov, Evan Jeffrey, Zhang Jiang, Cody Jones, Dvir Kafri, Kostyantyn Kechedzhi, Julian Kelly, Seon Kim, Paul V. Klimov, Alexander Korotkov, Fedor Kostritsa, David Landhuis, Pavel Laptev, Mike Lindmark, Erik Lucero, Orion Martin, John M. Martinis, Jarrod R. McClean, Matt McEwen, Anthony Megrant, Xiao Mi, Masoud Mohseni, Wojciech Mruczkiewicz, Josh Mutus, Ofer Naaman, Matthew Neeley, Charles Neill, Hartmut Neven, Murphy Yuezhen Niu, Thomas E. O'Brien, Eric Ostby, Andre Petukhov, Harald Putterman, Chris Quintana, Pedram Roushan, Nicholas C. Rubin, Daniel Sank, Kevin J. Satzinger, Vadim Smelyanskiy, Doug Strain, Kevin J. Sung, Marco Szalay, Tyler Y. Takeshita, Amit Vainsencher, Theodore White, Nathan Wiebe, Z. Jamie Yao, Ping Yeh, Adam Zalcman. 2020-04-08. Hartree-Fock on a superconducting qubit quantum computer. https://doi.org/10.1126/science.abb9811

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