Everyone is welcome to attend the online QuSoft seminar with:
Tim Coopmans, title 'LIMDD: A Decision Diagram for the Classical Simulation of Quantum Computing Including Stabilizer States'
Efficient methods for classically simulating quantum computing are crucial for quantum circuit optimization and studying noise resilience
of quantum circuits, among others. Decision diagrams (DDs), a well-studied data structure traditionally used to represent Boolean
functions, have been empirically shown to outperform state-of-the-art simulators in some regimes, with as one of the highlights the 37-qubit
simulation of Shor's factoring algorithm. Theoretically, however, the limits of DDs for quantum computing are not well understood. In this
talk, I will explain recent results on bridging the gap between existing DD-based structures and the stabilizer formalism, a well-studied method
for efficiently simulating a subset of quantum computation.
Among other things, we prove that although DDs were suggested to succinctly represent important quantum states, they actually require
exponential space for a subset of stabilizer states. To remedy this, we introduce a novel decision diagram variant called Local Invertible
Map-DD (LIMDD), and show that LIMDDs are strictly more powerful than both DDs and the stabilizer formalism.
Arxiv paper: https://arxiv.org/abs/2108.00931
(Joint work with Lieuwe Vinkhuijzen, David Elkouss, Vedran Dunjko and Alfons Laarman.)
Yaroslav Herasymenko, title 'Methods for Entangled State Preparation from Many-Body Quantum Theory'
Abstract: The problem of preparing entangled states with quantum hardware has historically enjoyed an influx of methods from the theory
of many-body quantum physics. I will overview three such solutions that recently emerged in my own work. Firstly, I will describe a rigorous
approach to constructing efficient variational quantum ansatzes, obtained using many-body perturbation theory and stabilizer formalism.
Secondly, I will outline a systematic method for ground state preparation on digital hardware based on the idea of quantum cooling.
Finally, I will overview how introducing feedback can help to accelerate measurement-driven preparation of entangled states. The methods of doing so can be linked to various concepts in many-body theory and have the potential to shorten the preparation time by at least a factor of 10. In addition to these three methods, I will describe one of my ongoing projects, which has to do with the efficient classical initialization of
variational quantum algorithms.
If you like to attend, please send an email Jop Briet or Subha Patro for the zoomlink.