The answer is a mixture of yes, no, and all the space in between—ironic, given that this is the basic premise of how quantum computing works. Functional quantum computers exist and are even capable of doing some work, but they’re far from fully operational models at this time.

In this article, we’ll dig into questions such as is quantum computing real, how many quantum computers are there, and who has quantum computers.

## Is Quantum Computing Real?

Yes, quantum computing is a conceptual reality. In our article “What Is Quantum Computing,” we dig into the basic premise of quantum computing and explain some of the core principles of how it works.

Building on this theoretical foundation, quantum computers do exist. However, in the grand scheme of what quantum computers can theoretically do, it’s a stretch to say that these elemental models are fully working representations, particularly when you consider the potential quantum computing has.

Mike Loukides, vice president of emerging tech content at IT learning firm O’Reilly Media, estimates that it would take 1,000 logical qubits (the quantum mechanical analog of a traditional bit) to accomplish any real work. Each of those would take approximately 1,000 physical qubits. IBM, a global leader in quantum computing development, announced in late 2021 that it had just surpassed the 100-qubit barrier with a 127-qubit quantum processor. This is far from the estimated 1,000,000 qubits needed for a fully functioning quantum computer. As Loukides says, “We’ll probably get there, but not next year.”

## How Many Quantum Computers Are There?

Many research centers have performed quantum computing calculations, but these would likely not meet the definition of a quantum computer that the typical reader has in mind. For example, in 2000, the Los Alamos National Laboratory announced that scientists had developed a seven-qubit quantum computer—housed within a single drop of liquid. Because the qubits were composed of particles in the atomic nuclei of an acid, most people probably wouldn’t consider this to be a working quantum computer.

Additionally, it’s critical to understand the basic difference between quantum gates and quantum annealing. Although the technicalities are quite complex, the applications of each technology may make them easier to comprehend.

Quantum annealing is used to find efficiencies and optimization in situations where the parameters are fixed. For instance, the traveling salesman problem is one example of how quantum annealing can be applied. In this theoretical logic dilemma, a salesman is given a list of cities and asked to find the shortest possible route to visit each location only once and end the journey by returning to the original city. Researchers already know the limits and are looking for optimal efficiencies.

Quantum annealing can solve these types of problems but isn’t used to answer more open-ended questions. For example, asking which cities the salesman should visit is beyond the capacity of quantum annealing. In quantum gate technology, computers search for answers to problems without previously defined solutions. To count all quantum gate computers, we must open the definition to include laboratory “computers” that exist within a single drop of acid. The more we refine what we mean when asking “how many quantum computers are there,” the more specific the answer we can find.

## Who Has Quantum Computers?

Beyond experimental and theoretical laboratory applications, several organizations have built working quantum computers. IBM, Google, Honeywell, Intel, and Microsoft top the list of gate model quantum computer innovators. D-Wave is a company that specializes in quantum annealing computers, and many universities have built various types of qubit circuits, applying them in different ways.

One of the things that makes it so difficult to define what a quantum computer is, how many quantum computers exist, and who has quantum computers is that we’re dealing with such a highly theoretical space. Because quantum computing is so cutting edge, there is frequent disagreement regarding every quantum computing assertion.

For example, in 2019, Google claimed that it had achieved quantum supremacy by solving a problem in 200 seconds that classical supercomputers would have taken 10,000 years to compute. However, scientists at IBM disagreed, showing that it would have taken a supercomputer only two and a half days to solve the problem. Although this demonstrates the tremendous disparity between how even industry leaders view the same issue, there’s little doubt that the advantages of quantum computing are enormous.

## Is Quantum Computing the Future of Computing?

Quantum computing offers the potential for a tremendous leap forward in computing technology in highly specialized uses. Still, experts disagree on whether quantum computers will replace classic computers. Because quantum computing operates at a fraction of a degree above absolute zero, the logistics and costs of operating quantum computers will likely always exceed what average users are willing to pay. Additionally, the capabilities offered by quantum computing will likely surpass what even a typical business would ever need.

A far more likely scenario is that quantum computers will form a third arm of computing power, where classical desktops are still used in everyday life, classical supercomputers are used on a broad scale, and quantum computers become more widely available for specialized research in areas such as pharmacology and meteorology.

## What Can We Do with Quantum Technology?

The European Organization for Nuclear Research (CERN) has access to the largest computing grid in the world. To run calculations for the Large Hadron Collider (LHC), it links 11 major computer centers worldwide, and these have access to 160 smaller computer centers. This effectively creates one giant supercomputer, but even with the collective computing power of humankind, CERN experiences limitations.

To give you an idea of how much of an advantage quantum computing could provide over classic computing, let’s compare the performance of humans to supercomputers. In 2018, Oak Ridge National Laboratory (ORNL) in Tennessee revealed the Summit supercomputer, the world’s fastest and smartest at the time. It could complete 200,000,000,000,000,000 calculations per second. Put another way, “if every person on Earth completed one calculation per second, it would take the world population 305 days to do what Summit can do in one second,” according to ORNL. Now, replace “person” with “supercomputer” and “Summit” with “quantum computing,” and you’ll get an idea of why scientists are ecstatic about the potential that quantum computing offers.

In the same way that supercomputers transform what desktop PCs can do by switching from serial processing to parallel processing, quantum computing can reinvent what supercomputers are capable of by changing from a binary bit to a qubit capable of leveraging superposition and quantum entanglement. As a general principle, quantum computing offers as much of a potential leap forward over supercomputing as the latter does over a human with a pencil.