Seminar of the Quantum Information Working Group: Jean-Philip Piquemal (Laboratoire de Chimie Théorique, Sorbonne Université)

The "Maison de la Simulation" and the "Quantum Information and Quantum Computing" working group invite you to a seminar given by Jean-Philip Piquemal (Laboratoire de Chimie Théorique, Sorbonne University)

Zoom link for virtual broadcasting: https://univ-lille-fr.zoom.us/j/95889688614?pwd=UUtmckVHUVlkbGRSQm14em5GZ2VRdz09

14:00-14:45: Jean-Philip Piquemal (Laboratoire de Chimie Théorique, Sorbonne Université)

Title: Hybrid quantum-classical Adaptive Variational Quantum Eigensolvers for quantum chemistry

Abstract:

Hybrid quantum-classical Adaptive Variational Quantum Eigensolvers (VQE) hold the potential to outperform classical computing for simulating quantum many-body systems. However, their practical implementation on current quantum processing units (QPUs) faces challenges in measuring a polynomially scaling number of observables during the operator selection so as to optimise a high- dimensional and noisy cost function. In this talk, I will present an extension of the ADAPT-VQE strategy denoted Overlap-ADAPT-VQE. The algorithm iteratively generates a compact quantum approximation of a classical target wave function through a quasi-greedy procedure that maximises, at each iteration, the overlap of the current iterate with the target. This is achieved by adding on-the-fly, the most relevant unitary operator from a finite size pool of admissible operators, with a selection criterion based on the gradient of the overlap of the ansatz with the target. I will also detail how the approach can be used for state preparation purpose and shows a first implementaion on a real quantum processing unit. Finally, I will present some initial results obtained with our in-house GPU-accelerated quantum emulator and explain how one can use it through a direct coupling with a quantum computer to perform full adaptive-VQE simulations.

• Overlap-ADAPT-VQE: Practical Quantum Chemistry on Quantum Computers via Overlap-Guided Compact Ansätze. C. Feniou, M. Hassan, D. Traoré, E. Giner, Y. Maday, J.-P. Piquemal, Commun. Phys., 2023, 6, 192 (Open Access), DOI: 10.1038/s42005-023-01312-y
• Sparse Quantum State Preparation for Strongly Correlated Systems. C. Feniou, B. Claudon, J. Zylberman, O. Adjoua, E. Giner, J.-P. Piquemal, 2023, DOI: 10.48550/arXiv.2311.03347
• Greedy Gradient-free Adaptive Variational Quantum Algorithms on a Noisy Intermediate Scale Quantum Computer.C. Feniou, B. Claudon, M. Hassan, A. Courtat, O. Adjoua, Y. Maday, J.-P. Piquemal, 2023, DOI: 10.48550/arXiv.2306.17159

14:45-15:15: Coffee break