Google's quantum supremacy FAQ (ภาษาไทย)

Giuseppe Davide Paparo, Markus Müller, Francesc Comellas +1 more

Frank Tavares

Google, in partnership with NASA and Oak Ridge National Laboratory, has demonstrated the ability to compute in seconds what would take even the largest and most advanced supercomputers thousands of years, achieving a milestone known as quantum supremacy.

Yosef Rinott, Tomer Shoham, Gil Kalai

In quantum computing, a demonstration of quantum supremacy (or quantum advantage) consists of presenting a task, possibly of no practical value, whose computation is feasible on a quantum device, but cannot be performed by classical computers in any feasible amount of time. The notable claim of quantum supremacy presented by Google’s team in 2019 consists of demonstrating the ability of a quantum circuit to generate, albeit with considerable noise, bitstrings from a distribution that is considered hard to simulate on classical computers. Very recently, in 2020, a quantum supremacy claim was presented by a group from the University of Science and Technology of China, using a different technology and generating a different distribution, but sharing some statistical principles with Google’s demonstration. Verifying that the generated data is indeed from the claimed distribution and assessing the circuit’s noise level and its fidelity is a statistical undertaking. The objective of this paper is to explain the relations between quantum computing and some of the statistical aspects involved in demonstrating quantum supremacy in terms that are accessible to statisticians, computer scientists, and mathematicians. Starting with the statistical modeling and analysis in Google’s demonstration, which we explain, we study various estimators of the fidelity, and different approaches to testing the distributions generated by the quantum computer. We propose different noise models, and discuss their implications. A preliminary study of the Google data, focusing mostly on circuits of 12 and 14 qubits is given in different parts of the paper.

Phil Wittmer

Robert Alicki

The recently reported experimental results claiming "quantum supremacy" achieved by Google quantum device are critically discussed. The Google team constructed a quantum chaotic system based on Josephson junction technology which cannot be reliably simulated by the present day supercomputers. However, the similar "supremacy" can be realized for properly designed micro-mechanical devices, like periodically forced Duffing oscillator, using the available technology of quartz clocks. It is also reminded that classical and quantum chaotic systems behave in a similar way. Therefore, in this case, one should speak rather about the "analog supremacy" than "quantum supremacy" what means that even now mechanical analog computers can outperform supercomputers when the computational task can be reduced to sampling of ergodic measures generated by chaotic systems.

Eric P. Ostby