It was declared in headlines around the globe, but what does it even mean? And what impact could this achievement have in our lives today, and in the years to come?
In the waning months of 2019, headlines claimed that Internet giant Google had achieved quantum supremacy—leading many to scratch their heads and ask, “What in the world is ‘quantum supremacy’?”
Answering that question requires us to explore one of the most fundamental and startling aspects of God’s creation: the world of quantum mechanics.
For a taste of how this strange realm of physics is being used to revolutionize computing, consider the quantum-mechanical concept of superposition. It is an odd property of matter, and an odd illustration can help us understand it better.
Imagine you take a photo of a zebra and look at the image on your computer. As you zoom in, you begin to see the image’s individual pixels. Where the zebra’s black stripes meet its white ones, you notice that some of the pixels are gray—some darker gray, some lighter, but definitely not 100 percent black or white.
In those cases, the pixels represent a sort of superposition: a mixture of black and white. The single pixel is forced to represent a superposition of multiple states—not purely black stripe and not purely white. Both states are represented in the single pixel, based on the percentage mixture of black and white zebra hairs in the small fraction of an image the pixel represents.
In a (very) roughly analogous way, according to quantum mechanics, subatomic objects we often think of as discrete “particles” are not quite particles at all, but rather exist in multiple states at once. As the pixel’s gray color represents a combination of certain percentages of black and white, a subatomic particle’s state is “fuzzy” and unclear, defined by a combination of all the different states it could have, based on their individual probabilities of happening.
The idea that particles are not always clearly defined objects with definite locations and states but can exist, instead, in indefinite locations and states—only probably existing here or there—is undeniably strange. But quantum theory’s value has been proven time and time again, providing the basis of much of our modern technology. It has unlocked a deeper understanding of processes as down-to-earth as photosynthesis and as cosmic as the fate of massive black holes.
But what can it do for computing?
Since the early 1900s, the basis of computing has been binary—representing information as a collection of ones and zeros. Using 1 to represent “true” or “on” and 0 to represent “false” or “off,” binary arithmetic is fundamental to the entirety of computer programming, from the apps on your smartphone to the life support systems on the International Space Station.
That basic unit of information—on or off, true or false, 1 or 0—has been dubbed a “bit,” a word derived from combining “binary” and “digit.” And as bits, each equaling only 1 or 0, are collected into larger and larger groups, they grow into bytes, megabytes, and gigabytes, representing increasingly larger amounts of information. For instance, if your computer can store 500 gigabytes of information, that means it has electrical architecture that can store 4,000,000,000,000 bits—four trillion ones and zeros. Everything on that computer is stored as a group of those ones and zeros.
The simplicity of the bit has proven a phenomenal tool that has enabled our complicated digital world to exist. But it has also been limiting, and the application of quantum mechanics promises a major upgrade. If a switch that can only be “on” or “off” is useful, what if it could be a mixture of both?
Enter the qubit. If a bit is like a pixel limited to only black or white, a qubit is like a pixel able to be both possibilities simultaneously as a shade of gray.
Where a classical computer’s bit is limited to a value of 1 or 0, a quantum computer’s qubit can exist in an indeterminate state that represents a kind of combination of both 1 and 0—a superposition of multiple conditions at once, based on the probabilistic laws of quantum mechanics. As such, qubits bring far more problem-solving power to a calculation than bits can. How much more?
That was illustrated by the results published in the science journal Nature on October 23, 2019. Google’s quantum computer, named “Sycamore,” was assigned a problem that it solved in about 200 seconds. Nature estimated that the same calculation, using conventional computing, would take the combined might of 100,000 “normal” computers up to 10,000 years.
“Quantum supremacy” is the milestone we’ve passed when a quantum computer achieves a result that is effectively impossible for classical computers. Solving a problem with one single processor in less than three-and-a-half minutes that would take 100,000 computers longer than the history of civilization itself to solve certainly qualifies!
Computer powerhouse IBM has disputed the claim, estimating that its own classically designed supercomputer could achieve the same result in two-and-a-half days. Yet even if IBM is correct, no one can deny that Sycamore’s achievement is significant. IBM’s supercomputer, nicknamed “Summit,” takes up the space of two tennis courts and is currently the fastest non-quantum computer on the planet. If Sycamore, which could fit in a closet, achieved in 200 seconds what would take Summit more than two days, we really are on the verge of something revolutionary.
And Sycamore represents only a crude, simplistic beginning to the quantum computers scientists envision. If it isn’t here yet, quantum supremacy is on the way.
The potential for quantum technologies to change the world becomes clear when we consider how vital “number crunching” has become in our lives. Quantum computing’s dramatic leap in calculation power holds the potential to help us design new building materials and medicines or accelerate the advance of artificial intelligence. We may see advancements we cannot now even imagine.
Some theorize that the universe itself acts as a vast quantum computer, “processing” the activity of its countless particles and forces from one end of reality to another. If so, as computers begin to more directly imitate nature’s own computations, new insights may open into physics, chemistry, and biology—even the architecture of the brain itself.
Yet mankind has not proven the best steward of such knowledge. On our path to learning more about how God’s remarkable creation works, we inevitably come to various crossroads regarding how we choose to use what we learn. Understanding God’s design of matter and energy has allowed us to harness the power of the atom—both to power our cities and to destroy them.
Understanding the strange, counterintuitive world of quantum mechanics will bring us to a similar crossroads. What decisions will we have to face when quantum computing is fully ours to wield however we wish? Will we have the character to properly apply what we learn from this aspect of God’s creation?
Sycamore’s success has put us on notice that we may soon find out.