What does quantum supremacy really mean?

Presented by Xavier Waintal, CEA Grenoble/PHELIQS

About a year ago, Google announced that they had reached a new milestone in quantum computing that they refer to as « quantum supremacy ». They claimed that their quantum chip had performed a task that would take thousands of years to simulate on the largest existing supercomputer. In this talk, I will first review the experimental findings. Then, I will challenge their claim and show that, while it would indeed require an exponentially large computing time to simulate a perfect quantum computer, simulating a real one with a finite fidelity is much easier. I will present how it can be done with quantum states compression techniques borrowed from many-body theory.