Last month as I was watching Matt Damon escape his existential crisis on Mars, I became fascinated by my cell phone’s ability to capture a 40-gigabyte file from a Russian database, process it on quad-core chip, and stream it in high definition on a 5-inch screen in the comfort of my bedroom. There’s more computing power in the palm of my hand than there was in the basement of Caltech 50 years ago. What exactly drove technology to this point? Look around and you’ll see that our world is surrounded by classical computers. Everything from the smoke detector mounted on your ceiling to the phone in your hand contains chips with millions of tiny transistors, on and off switches that limit our computing power.
Transistors are essentially switches that block and allow the passage of electricity. The modern transistor is analogous to a light switch without mechanical parts. When microchip companies originally began manufacturing transistors, they were on the order of several micrometers, or a millionth of a meter. For context, the width of a human hair is about 50 micrometers! Intel co-founder Gordon Moore observed in 1975 that the number of transistors per chip doubles approximately every two years. Moore’s Law is not a physical law, and the miniaturization of transistors has noticeably slowed.
Deep in the echelons of laboratories, material scientists and researchers are racing against the clock to surpass Moore’s Law. Driven tech companies are essential playing Honey, I’ve Shrunk the Kids with transistors. In 2013, we reached a miniscule width of 22 nanometers, or about 50 silicon atoms. We really are achieving mind-boggling nanotechnology that’s not locked away in some clandestine lab, but is accessible to all of us, including the 43% of the global population that owns a smartphone.
A modern computer typically contains billions of transistors, but as we try to squeeze more and more of them closer and closer, quantum mechanics become a problem. Objects on the nanoscale sometimes contradict rules that exist on the human scale. Seemingly contradictory things exist in quantum theory. For instance, we know that light sometimes behaves as if it is made of waves, just like the waves in the ocean, and other times light behaves like particles, a bit like a stream of tennis balls. Quantum theory goes against our instinct. We can’t just stand with our backs to a wall and expect to teleport to the other side, but electrons can in a phenomenon known as quantum tunneling. As transistors get smaller, quantum tunneling becomes an issue.
How exactly would quantum computers work? Instead of transistors switching between 0 and 1, quantum computers would use quantum bits (qubits), which instead of being 0 or 1, could be either, both, any value in between the two, and in many states at once. An easier way to think about this is to look at an instrument many of us played in elementary school, the recorder. When you blow through the recorder, a wave containing the basic note you’re playing and many overtones, or higher-frequency waves of the original note, exist. The one wave containing all other coexisting waves operates analogously to how qubits would work. It’s exciting to think of the possibilities available if we had quantum computers that not only store many states at once, but also process them at speeds millions of times faster than any conventional computer.
The world seems to be getting smaller as our lives and technology become more compact, but maybe that’s not such a bad thing.