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Wednesday, February 21, 2018
12:30 PM - 1:30 PM
CANCELLED-T-DO Conference Room (03-123-121)

Quantum Lunch

CANCELLED-Quantum Simulation of Chemistry on Near-Term Quantum Devices

Ryan Babbush
Google, Inc.

CANCELLED-Quantum simulation of the electronic structure problem is one of the most researched applications of quantum computing. The majority of quantum algorithms for this problem encode the wavefunction using N Gaussian orbitals, leading to Hamiltonians with O(N^4) second-quantized terms. We avoid this overhead and extend methods to the condensed phase by utilizing a dual form of the plane wave basis which diagonalizes the potential operator, leading to a Hamiltonian representation with O(N^2) second-quantized terms. Using this representation we can implement single Trotter steps of the Hamiltonians with linear gate depth on a linear array. Variational algorithms also require significantly fewer measurements to find the mean energy in this basis, ameliorating a primary challenge of that approach. We conclude with a proposal to simulate the uniform electron gas (jellium) using a low depth variational ansatz realizable on near-term quantum devices.

Host: Yigit Subasi