In October 2019, the Google Quantum AI team published a landmark paper using Random Circuit Sampling (RCS) to demonstrate a problem that their Sycamore quantum computer could solve in 200 seconds and would take 10,000 years to solve with the world’s fastest computer. supercomputer. This experiment, called the Quantum Supremacy Experiment (now called the “Beyond Classical” experiment), used 53 qubits with a gate depth of 20 levels. (See our in-depth report on this here.)
Almost immediately, several challenges came to the experiment from both the classical and quantum sides. First, IBM published a blog explains how a different classical approach can implement this calculation in 2.5 days instead of 10,000 years. About two years later, a Chinese group replicated the experiment using 60 qubits down to a gate depth of 24 levels. And another Chinese group shows how calculations can be completed in 5 days using a bunch of 60 NVIDIA GPUs.
One important lesson from this is that classical computing technology is also not standing still. There continues to be significant innovation in using classical techniques to solve problems previously thought to be unsolvable. So the quest for quantum superiority is one in which the bar continues to be raised year after year.
However, an important characteristic of the RCS problem, like many other quantum-oriented algorithms, is that the resources needed to solve it double each time you add qubits. So Google has re-run this experiment using a second generation Sycamore processor that uses 70 qubits to a gate depth of 24 levels and they have once again demonstrated that their Sycamore processor can outperform even the fastest classic systems using the latest software techniques.
To read more about this new experiment, you can check out the new arXiv preprint from the Google Quantum AI team Here.
April 29, 2023