Quantum for dummies – Part 3 – Applications

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If you’re still with me after the section on interpretation, you’re probably wondering whether quantum stuff can actually be useful. The answer is a definitive YES.

Quantum effects are not only responsible for many useful and cool technologies around us, they can be useful to help explain the very nature and origins of the universe in which we live (but more on that in the next installment).  For now, let’s focus on the applications.

All electronics

We all know how pervasive electronics is in the modern world – computers, TV, radio, communications of all sorts, medical instruments etc etc. You may be interested to know that electronics would not be possible without quantum effects. The good ol’ quantum effect allows us to build things called semiconductors, which are the basis of all electronic devices. Without getting too technical, semiconductors can only work because of a thing called ‘quantum tunnelling’. This is a strange effect whereby an electron can penetrate a barrier, even when classical physics tells us that is has no right to. In other words, if it were not for weird quantum behaviours of sub-atomic particles, semiconductors, and hence electronics, would not be possible. Right, that’s taken care of 90% of all technology on the planet.

Emerging applications

But, there are other more esoteric applications that we don’t have access to on a day to day basis.

For example, the quantum computer, which is a rapidly evolving area.  Although still in their infancy, quantum computers are a reality, and promise a huge leap forward in processing power. At the heart of this field is the fact that we can use the properties of quantum effects, like superposition and entanglement (remember those?), to produce computing ‘bits’ which are more complex than our current approach.  Let me quickly explain. The ‘bits’ in the computer on which you’re probably reading this article have two logic states – 0 and 1. They are on, or off. This means to represent the alphabet, for example, we need at least 5 bits, giving us 32 different possible combinations. But when we talk of quantum bits, or qubits, each can have more than two states. If we assume a modest 3 states, this means we go from 32 different combinations, up to 243 combinations. For 4 possible states, it’s now 1024 combinations.

As well as the increase in storage capacity this implies, the major advance is the ability for parallel processing – that is, doing more operations in parallel.

While current technology has only demonstrated this using a few qubits, it’s an exciting prospect. In addition, we’re also now getting on top of some of the other engineering challenges, such as micro wiring to allow quantum computers to interface to the real world.

Another great application, and much more mature than quantum computing, is quantum cryptography, which I mentioned last time. This allows us to design very high security communications based on the entanglement property. This is a bit complex to go into at the moment, but wikipedia has quite a good discussion on it here. Although complex, this will  ultimately have mundane applications, like making sure your online banking transactions are secure.

Superconductivity is also a fascinating application of quantum mechanics, and harnessing it’s effects will in time provide huge technological leaps. This phenomenon occurs when electrical conductors, like wires or other materials, are coaxed into having zero resistance – which means they can conduct a current without generating heat, and hence without losing energy. This has implications at the large scale, for example, long power lines that don’t dissipate power along the way, and at the small level, with computer components that can run cool and fast.

To finish off this short section on applications, this video has a mind-blowing example of superconductivity and quantum mechanics at work. It’s demonstrates a thing called quantum locking, which demonstrates that quantum effects have implications for the macroscopic world at very low temperatures. What is shown in this video could not possible be explained with classical mechanics. Very, very cool. I want one.

See you next time, for a modestly-titled discussion on Origins of the Universe.

On to Part 4 – Origins of the Universe