At GQI we see a lot of roadmaps from the quantum providers and fully expect that there will be continuing advances in the capabilities of both quantum hardware and quantum software over the next several years. In fact, we believe that we will soon start seeing organizations utilizing quantum technology for production purposes within the next few years. (Some call that Quantum Advantage while others call it Quantum Utility, but in this article we will call it Quantum Production to distinguish it from one-off proof-of-concept experiments versus those running the use cases on a repeated, regular basis.)
Although we initially did not expect to see fault tolerant quantum computers until the 2030’s recent advances now lead us to believe that we will start seeing what we call early fault tolerant quantum computers (FTQC) available in the second half of this decade. One way we measure the capability of a quantum computer is a measure we call Quops, standing for successful quantum operations. And we classify quantum evolution according to the following eras: Intermediate, Early FTQC, Large Scale FTQC, and mature Turbo FTQC. For error corrected machines, we expect to see Early FTQC machines available within the next five years that can achieve capabilities in the MegaQuops or GigaQuops regimes. These machines will offer a few 100 or so logical qubits and that should be enough to run some useful applications, but still won’t be powerful enough to run intensive quantum applications like Shor’s algorithm that will require machines with TeraQuops capabilities. We do not expect those Large Scale FTQC machines to be available until the 2030’s and they will provide thousands of logical qubits for calculations.
On the other hand, we also see advances occurring in more capable NISQ processors along with associated algorithms that may be able to also run useful applications in the 2025-2029 timeframe. We have already seen a few companies demonstrate two-qubit fidelities in greater than 99.9% for their physical gates. And we have also seen advances in algorithms to get the most out of those physical gates. This software includes hybrid classical/quantum architectures, variational quantum algorithms, error mitigation and suppression techniques, circuit knitting, zero noise extrapolation, probabilistic error cancellation, and other classical post processing to improve quantum results. Moreover, the roadmaps we have seen indicate we may have available NISQ processors with 10,000 of physical qubits in the second half of this decade.
So end users may have an interesting choice soon. Do they want to use an Early FTQC machine that provides about 100 logical qubits with 2Q fidelities of greater than 99.9999% or do that want to use a NISQ machine that contains around 10,000 physical qubits with with 2Q fidelities of 99.9% or perhaps 99.99%?
Many quantum researchers are skeptical that the people will ever be able to run useful applications on a NISQ quantum computer. Besides the fact that these machines still have some remaining noise issues, one of the other reasons is that many of these applications would rely on heuristic algorithms such as QAOA or VQE which no one can theoretically prove will work. People will just need to try them out and see if they work or not. On the other hand, there does exist theoretical proof that certain algorithms, such as Shor’s algorithm, can run on a fault tolerant quantum computer and provide an accurate answer. However, we would remind our readers that many of the classical AI algorithms that have become popular in recent days are also heuristic and computer scientists do not yet have a theoretical proof that they should work. Yet, of course, these AI algorithm do work.
We are not at the point yet where we can definitely say which quantum applications will be able to provide commercially useful results on which machines. However, the one thing that makes us optimistic is the diversity of innovative approaches and rapid advances that organizations are making in both hardware as well as software get to where the systems can be used for Quantum Production for useful applications. Although some of these innovative approaches will fail, we fully believe that others will work and start delivering within the next few years on the promise of quantum computer. The applications in production may only be a handful for the next few years, but this initial small number will grow substantially in the 2030’s as more Teraquop large scale FTQC system become available enabling many more algorithms to be run successfully.
So while some may be of the belief that there will be a hard demarcation between when the NISQ era will end and the FTQC era begins. In reality, these eras will overlap and we will see a gradual transition between when one ends and the other begins.
August 3, 2024
