Prof Seth Lloyd researches quantum computing at MIT, is the designer of the first feasible quantum computer (looks like a beer keg, featured on the left), and is the author of a fascinating book – Programming the Universe: A Quantum Computer Scientist Takes On the Cosmos, which I’m in the process of reading right now.
This book is the story of the universe and the bit. The universe is the biggest thing there is and the bit is the smallest possible chunk of information. The universe is made of bits. Every molecule, atom, and elementary particle registers bits of information. Every interaction between those pieces of the universe processes that information by altering those bits. That is, the universe computes, and because the universe is governed by the laws of quantum mechanics, it computes in an intrinsically quantum-mechanical fashion; its bits are quantum bits. The history of the universe is, in effect, a huge and ongoing quantum computation. The universe is a quantum computer.
One of Seth Lloyd’s other works is showing the ultimate physical limits to computation, in effect a boundary to Moore’s Law of exponential growth in computing power. As transistors and connections half in size, computational power doubles since chips and integrated circuits now house twice as many parts. The physical limit of conventional electronics fizzles out at a nano level, and we will be forced to venture into the quantum world to sustain advances in computer technologies.
But there is no particular reason why Moore’s law should continue to hold: it is a law of human ingenuity, not of nature.
A quantum computer is based on the principle of quantum mechanics – the fact that a qubit, a quantum bit, can be 1, 0, or sometimes both. It’s weird, it’s complicated, but “you don’t have to understand the nature of things in order to build cool devises”. In this case, the cool quantum computing devise leverages quantum mechanics to perform multiple computations at the same time, in parallel.
The other neat thing about these quantum computers is that they’re also storing a bit of information on every available degree of freedom.
Conventional computers are incredibly fast at computing a linear set of instructions. Electron information traverses computer circuits much faster than nerve signals in the human brain (as the latter relies on chemical reactions), but even sophisticated neuron networks cannot compete due to a simple fact that they have no more than a few parallel threads going at the same time, while the human brain is incredibly well suited for multi-tasking. A quantum computer, due to its multi-threaded nature, has the potential to not only exceed the physical limits of the modern computer paradigm, but surpass the human brain itself. As such, Seth Lloyd and his research were featured in a part of BBC’s documentary on Human 2.0
This prospect of a quantum brain brings promise of a surge in information processing capacity, and the fear of the same. The robotic overlords of The Matrix universe are most likely to be powered by quantum computers. The future is unknown, but it is a fair assumption that computers will fundamentally change in my lifetime. For now, the universe continues on with its quantum computation of self. And I take comfort in Seth Lloyd’s sense of humour:
The universe is not an electronic digital computer, it’s not running some operating system, and it’s not running Windows.