Quantum computing, the paradigm, is a potential salve to the constraints that Moore’s Law and other physical factors – heat generation, energy efficiency - are beginning to impose upon classical computing.
For the uninitiated, classical computing is the world you know and indeed follows the rules of the world you can see, feel and interact with. It utilizes small form factor, highly standardized integrated circuits, typically manufactured using a silicon substrate (in more esoteric applications you might find gallium arsenide). These ICs contain many millions of transistor gates which can store a zero or a one value; binary code is the key to classical computing. When you click, “Like”, your computer translates that through a number of different abstraction levels until the CPU hears a binary string, and then outputs a binary string based on your instructions.
Advances in classical compute power have been a function of many things, but the number of transistors packed onto any one integrated circuit die has been one of them. The Moore’s Law of which many of us have heard, but few of us truly understand, was coined by Gordon Moore, founder-CEO of Fairchild Semiconductor and of Intel, and has to do with the number of transistors per chip. But you’ll hear Moore’s Law cited as a catchall for the mounting challenges in conventional computing, be it heat output, power consumption, ability to deal with complex uncertain multivariate calculations, and so on and so forth.
Quantum computing is not based upon ones and zeroes, but instead on probabilities and multiple simultaneous truths. You might think of classical computing as the Bauhaus of computing – the epitome of the Enlightenment Age. Linear to the last. And you might consider quantum to be truly postmodern in nature; facts and alternative facts being absolutely compatible within quantum logic.
A quantum computer doesn’t operate using transistor gates occupying only binary states – bits with value one or zero. It operates using ‘qubits’ with a value of one or zero or both. Qubits exist as energy states within superconducting loops in a quantum computer, the same way that bits exist as voltage at a transistor gate. Qubits can be a single value of zero or one – once a computing problem is solved, a qubit has reached its lowest energy state (which could be zero or one); but in the main occupy multiple simultaneous values.
If classical computing is ideally suited to linear tasks such as arithmetic, measurement, storage and so forth; quantum is ideally suite to nonlinear, multivariate and/or iterative tasks such as optimization problems. The simple question of route optimization isn’t really a simple question. The real question is multivariate. It is, “in what order should I deliver these Amazon parcels, given the weather, the cost of gas last week when I filled the tank, the degree of irritation each specific customer experiences when I am late, the proclivity of customers with irritation level X to switch from Amazon to other vendors, and the specific-customer profitability of each customer on my route”. The data – the variables – required to answer the question can be stored in any typical, classical database. But solving that problem efficiently and quickly? That’s better suited to a quantum device.
Unfortunately, you can’t buy a quantum laptop yet. In fact unless you can mainline liquid nitrogen into your home (which may cause an unusually robust family argument about whether to turn the heating up or not), you can’t run any kind of quantum computer at all. On account of they look a lot like this: