Reacción a "Reactions: study shows usefulness of quantum computer in practical scientific applications"

The paper by Kandala et al. is a paper of excellent quality, demonstrating the computational power of IBM's 127-cubit quantum computer. The content of the paper is quite technical, focusing on questions such as the simulation of physics problems on these computers, the extraction of quantitatively good predictions despite the imprecision of the computer, and the comparison with other simulation techniques using conventional computers that quantum physicists have perfected in recent years.  

The main message of the paper can be summarised in three statements:  

1. The quantum computers we have, although imprecise, can simulate problems of interest to physics that are of high complexity. In particular, this work has focused on simulating what is known as the "Ising model with transverse field", a fundamental physical problem in the study of magnetism.  
2. Although the quantum computer makes errors (cubits lose coherence, operations are not 100% accurate, etc.), the structure of the errors it makes is not arbitrary. Thanks to this, IBM has perfected a protocol that makes it possible to cancel the errors introduced by the quantum computer, obtaining very precise quantitative predictions.  
3. There are other simulation techniques that physicists use to study this type of problem on large "classical" computers. In this paper they have applied two such methods, known as "tensor networks", and found that they produce less accurate results than the quantum computer.  

This is extremely interesting work, and helps to reinforce the usefulness of quantum computers in scientific applications, even in scenarios where we do not have perfect cubits and error correction. After this work, the existence of computers with 413 cubits, such as the Osprey chip, where this type of problem is currently impossible to tackle with tensor networks, becomes even more attractive. It also opens up important questions about what other physical problems can be studied on these processors and whether the error mitigation techniques created by IBM will have the same effect on them.  

Is the result definitive? Not necessarily. Just as Google's work on quantum supremacy piqued the interest of scientists, who developed new simulation methods now capable of reproducing that experiment, it is possible that other scientists will improve the state of the art in "tensor networks" and match or surpass what this processor can do with 127 cubits.