Quantum computing is still the province of specialized programmers—but that is likely to change very quickly
Currently, quantum computing researchers and enthusiasts need to know quantum programming; it’s simply a must. Soon, though, all they will need is a quantum app store and a line of code. Not an app store like in your smartphone, but similar to a code repository of today, such as GitHub—a type of digital library where software developers make the code they have written available to anyone. And in the near future, developers will be able to put in their lines of code that will call on quantum computers to deal with specific tasks a regular computer can’t.
I predict that quantum computers will undergo the same stages of development as classical computers have over multiple decades—but much faster, within just this decade.
A decade ago, there were just a few dozen research groups who could code in quantum. When IBM launched its online platform Quantum Experience in 2016, giving everyone free access to quantum processors through the cloud, that number grew to a few thousand within just a week. Four years later, the number of programmers experimenting with quantum algorithms—what the community calls quantum circuits, the sequences of instructions that define commands for manipulating data and making a quantum computer work—is in the hundreds of thousands. And soon, millions of software developers in the IT mainstream will start building on that effort and designing a myriad of quantum circuits for everyone to use.
This evolution will parallel the same stages of development as classical computers have over multiple decades—but much faster, within just this decade. Remember Alan Turing? He developed his theory of software in 1936, jump-starting computer science and software engineering. Four decades later, it was still the case that only those who knew how to write software were able to use mainframe computers. And in the 1970s, when companies like IBM and Apple began building and selling the first personal computers it was often left to software enthusiasts to write applications that would run on them.
But rapidly, software businesses took the lead, and as personal computers became more mainstream, users could assemble their own software stack without having deep computer knowledge. We saw a repeat of this with mobile devices in the 2000s—very quickly, people with no programming experience began creating apps and designing Web sites. Today, all they have to do is input a simple line of code into a templated program and, in the background, the wheels are turning automatically.
Quantum computers hold the same promise. First, enthusiast-programmers; then, developers; and eventually, quantum circuit repositories—or perhaps libraries—with both open-source and copyright-protected circuits, a natural extension of the software ecosystem of today.
This is the inevitable next step from what companies and university labs have been focused on over the past few years: building qubits. These basic units of quantum information are analogous to the much more familiar bits used by classical computers, simple binary digits that can have a value of either 1 or 0, true or false. Qubits, on the other hand, can be in a superposition of 0 and 1 states. In our daily life, we don’t see superposition when it comes to objects—only with waves. But in the realm of the very small, particles can be in multiple states at once. Atomic nuclei with two spin orientations can do it, photons with two directions of polarization—and, in the case of IBM quantum computers, qubits made from superconducting electric currents.
Today, qubits are not high-performing enough for a quantum computer to outmatch a classical machine in a useful task. But quantum computers are rapidly getting better; we are getting pretty good at making qubits, and the theory behind the next steps is solid. We are executing a road map to make qubits with very low noise, meaning as free from the influence of external disturbances as possible. Any noise disrupts the quantum realm, making the fragile superposition collapse into the qubit’s final state, which is always 0 or 1. Once we have enough of such low-noise qubits—a few hundred—we will apply special error-correcting codes to fix or mitigate remaining problems and to be able to run more complex quantum circuits.
Already, when just a few dozens of qubits limit us to moderate-size circuits, quantum aficionados all over the world are busy creating code to run on our quantum computers, using the IBM Quantum Experience. To create their circuits, they code using Qiskit, an open source software development kit we introduced in 2017. Qiskitters have already designed billions and billions of quantum circuits. In early May, during IBM’s Digital Think conference, nearly 2,000 people from 45 countries took part in our Quantum Challenge—and using 18 IBM Quantum systems through the IBM Cloud, ran more than a billion circuits a day on real quantum hardware.
Today, these quantum enthusiasts have to know quantum programming, gates and circuits. If they don’t, they can’t write code for a quantum computer, and can’t create or use a quantum circuit. But that’s only temporary, as we are still at the dawn of the age of quantum computers. It’s just a matter of time before developers start designing more and more circuits for their specific purposes, from machine learning, to optimization, to scientific calculations. That will lead to quantum circuit libraries for everyone to benefit from. You’ll simply have to write a line of code in any programming language you work with, and the system will match it with the circuit in the library and the right quantum computer—the one with the most appropriate configuration of the chip, the way the superconducting wires are put together to join the qubits.
Frictionless quantum computing. Just a line of code, that’s all it’ll take to get a result on your classical machine through the cloud—while behind the scenes, invisible to the user, the quantum mystery will unfold, with superposition, entanglement and interference.
When we began our current line of investigation, the goal was to study the structural property of the Clifford group, describing a set of transformations that generate entanglement, play an important role in quantum computing error correction, and are used in (randomized) benchmarking. In a series of one-thing-leads-to-another findings, however, we ended up discovering a new mathematical proof of quantum advantage – the elusive threshold at which quantum computers outperform classical machines in certain use cases.
The ability to harness quantum-mechanical phenomena such as superposition and entanglement to perform computation obviously poses a number of difficulties. Add in the need to make these systems perform meaningful work, and you’ve raised the stakes considerably. Creating a pipeline of talented, well-trained academics and professionals who can meet those challenges was the subject of IBM’s July 28 virtual roundtable, “How to Build a Quantum Workforce.” Watch the replay, here.
IBM recently launched several initiatives to help inspire new students and begin building tomorrow’s quantum computing workforce. Our Quantum Educators program, in particular, provides professors and students with access to IBM quantum computers as well as the latest learning resources we’ve developed to help them get started programming and experimenting on quantum computers.