Quantum Computing
Not Just Science Fiction
The modern computing we use everyday has evolved rapidly over the last century. While not the product of a single inventor, modern computing systems resulted from a steady building upon of brilliant ideas and inventions that lead to breakthroughs in both hardware and software. Todays systems all rely upon the storage and transference of information via binary bits — zeroes and ones. Every program you use and piece of information you store or send is ultimately made up of millions of these bits in some combination of ones and zeroes.
Bits are sufficient for most practical purposes, but they do not accurately reflect the way the universe actually works. In nature, things are not simply “on” or “off”. Things are uncertain. And even the best supercomputers are not good at dealing with uncertainty.
This uncertainty is due to the nature of matter when observed at the most basic, particulate scale. The smallest building blocks of matter behave in a very unusual way — famously described by Albert Einstein as “spooky action at a distance” — based on quantum mechanics. Quantum mechanics is the rule book of physics, which manages chemistry, which is the bedrock of biology. So for scientists to accurately simulate any of the above, they need a better way of making calculations that can handle uncertainty. Enter, quantum computers.
How Does Quantum Computing Work?
Every NFL game starts with a coin toss to determine who will receive the ball first. The coin toss is used because it evens the odds — two teams and two possible outcomes. Fifty-fifty. But what if one of the players calling the toss were able to take into account additional parameters — such as the force imparted to the coin, the height at which it lands and the air resistance — he would then be able to predict with much greater certainty the outcome of the toss. This is precisely what a quantum computer is able to do. Quantum computers are able to predict the outcome of a coin toss with 97% accuracy.¹
The increased computing power of quantum machines is thanks to a quantum bit that is non-binary, instead existing on a spectrum of zero to one. Quantum bits — qubits — work on the principle of quantum physics known as superposition. Just like Schrodinger’s Cat, who is both alive and dead until observed by a human, a qubit can exist as both a zero and a one simultaneously. This ability to account for all possible outcomes allows quantum algorithms to maintain a polynomial time complexity. When contrasted with exponential time, the implications of quantum computing are huge.
Implications of Quantum Computing
Quantum computing is in its infancy — think back to pictures of computers from the 1940s and 50s that occupy entire warehouses, that’s where quantum computers are today — and the full picture of what may be possible is still developing. As Google and IBM race to build the best quantum computer, interests, financial and otherwise, have boomed and served as a catalyst to further explore quantum computing possibilities.
The most immediate interest in quantum computing is cryptographic. Current cryptography standards rely on the fact that no one has the computing power to test every possible way to descramble data once encrypted. Quantum algorithms bely this. What would be impossible for a classical computer to decode in less than thousands if not millions of years, quantum computers could decode in hundreds of seconds. This is known as “quantum supremacy” and was achieved by Google in 2019.² Other implications include the scientific — drug discovery and material science — and the economic — financial modeling.
Future of Quantum Computing
Currently, nearly all of the implications of quantum computing remain theoretical because of the unstable nature of qubits. Today’s most powerful quantum computers are less than 100 quibits. In order to maintain superposition, qubits must be kept at near absolute-zero — colder than outer space. And due to their quantum nature, the mere act of observing them can throw them out of superposition. This is currently the main obstacle that the field is trying to overcome.
- “A Beginner’s Guide to Quantum Computing”- Shohini Ghose, TED Talk, 2019. https://www.youtube.com/watch?v=QuR969uMICM
- https://www.nasa.gov/feature/ames/quantum-supremacy