What is Quantum Computing (And Why Do We Need It)?

If there's one technology that's sure to get computing experts excited about the future, it must be quantum. This is a term that's taken on somewhat of a mythical meaning over the last few decades - science-fiction writers have used it as a shorthand for many as-yet unreached levels of technology for decades. Yet the reality could be set to be even more revolutionary than we could have ever imagined.

But what exactly is quantum computing all about, and will it really deliver on the hype that's attached to it?

What is quantum computing?

Essentially, quantum computing is a fundamental change in how machines go about processing data. Traditional computers - no matter how powerful or complex they are - ultimately boil down to a series of bits. This is the smallest possible unit of data and can be in one of two states, either 'on' or 'off', represented by 0 and 1 respectively. All computing is based around transistor gates that open or close to determine which value a bit will have.

With enough transistors, computers can perform incredibly complex operations, but naturally, there are space limitations, so transistors have had to get smaller - these days, they’re only a few atoms across. However, this creates new problems, because if they get much smaller, they cease to work, as electrons can simply bypass the gates they encounter whether they are on or off, theoretically putting a cap on how much computing power we can fit into a given space.

To solve this problem, we have quantum. The term essentially refers to some of the tiniest interactions made by particles, and at this level, the rules of physics we depend on to understand the universe simply don't apply. Even Einstein couldn't get his head around it, describing quantum entanglement as "spooky action at a distance". But researchers have sought to take advantage of the unusual properties particles have at this level to overcome the limitations of traditional computing.

In quantum computing, the smallest unit of data is not the bit, but the qubit. Like a bit, this can be set to one of two states - 0 or 1 - but unlike a bit, it is not as simple as just being on or off. Thanks to the quirks of the quantum level, a qubit can also be in a combination of both states, called a superposition. Sometimes, this is described as being both 0 and 1 simultaneously, although this isn't entirely accurate. Rather, it could be anywhere between completely 0 and completely 1 - but the catch is, as soon as we actually measure a qubit, it collapses into one of the two definite states.

This can be a lot to get your head around, but the upshot is, superposition means the amount of data that can be stored grows exponentially as the number of qubits increases. A group of 20 qubits can hold more than a million values at once.

4 benefits of quantum computing

There's some serious high-level physics going on when it comes to quantum computing - we haven't even touched on properties such as quantum entanglement or quantum gates yet. But what you really need to know, in computing terms, is that whereas a traditional computer running an operation on a set of data would have to proceed through every bit one by one, quantum computers can process it all simultaneously.

So what does this mean in real terms? Quantum computing won't be suitable for every scenario, but where it can be used, the effect it can have on certain operations is immense. Here are a few areas where quantum computing could change everything.

1. Database processing

As noted above, one of quantum computing's great strengths is its ability to perform many operations simultaneously, which comes in very handy if you're trying to look something up in a large database. With normal computing, an application would have to check every record in the database one at a time to determine if it matches the user's query, but with quantum, it can check many records at once.

This hugely cuts down the time it takes to get an answer, making it much more efficient to get results. As the amount of data held around the world continues to explode, and database sizes become too much for even the fastest traditional computers to cope with, ways to speed of this processing will become vital in deriving new insights quickly and cost-effectively.

2. Security

One of the most common uses for quantum is likely to be in boosting the security of digital encryption solutions. At present, most encryption works in much the same way - an algorithm converts entered data into an encrypted format, and a related algorithm is able to decrypt it back again.

Theoretically, the biggest weakness of this is that by trying every possible option for the decryption algorithm, someone could break encryption by brute force. However, the big barrier to this is that it would take an unfeasibly long amount of time to test every possible solution.

But with quantum, this restriction doesn't exist because, as discussed above, the technology lets people run many queries simultaneously, which could potentially make the entire encryption technology instantly insecure. To combat this, new solutions will be required that quantum technology can't break.

3. Running simulations

Perhaps among the most exciting applications for quantum will be its ability to run more large-scale, accurate simulations. Currently, most simulations are held back by the vast amounts of processing power required to run them, as well as a lack of accuracy.

But by running these using quantum computing, the amount of parameters and variables they can analyze at once goes through the roof, allowing researchers to experiment on scales that would take classical computers years or even decades to run.

4. Artificial intelligence

Huge strides have been made in recent years in the world of artificial intelligence (AI), but many believe that the holy grail of the technology - computers that can think, learn and adapt with no human intervention - will only be possible with the computing power provided by quantum.

That may still be a way off, but quantum computing can also help improve both the speed and efficiency of some of the most complex optimization problems AI is currently used in. For example, large factories may use machine learning to help maximize output by identifying how each individual process and component could be used most effectively, and quantum computers can help deliver insights faster and more accurately, leading to streamlined output, reduced waste, and lower costs.

How quantum computing will change the world

The real-world implications of these benefits could be huge. One of the biggest and most-talked about applications for quantum computing is in the medical sector, where the simulation power of the technology has the potential to transform our understanding of the human body and help in the development of new drugs.

One of the ways it can do this is by speeding up molecular comparisons and simulation. This is an important process in early-phase drug design and discovery, but the use of this today is limited only to molecules up to a certain size, due to the processing limitations of classical computers. However, quantum computers make it possible to compare molecules that are much larger, which opens the door for more pharmaceutical advancements and cures for a range of diseases.

It doesn't stop there, as there are some who predict that quantum computing could help solve some of the most pressing issues facing the world today. For example, modelling molecular interactions could also help scientists develop new agricultural products that improve fertilizers and cut greenhouse emissions, thereby helping tackle world hunger while minimizing the environmental impact of food production.

Quantum computing may be closer than ever, but it's still a relatively new technology when it comes to real-world applications, and as yet, many of its benefits remain theoretical. However, as understanding of the technology grows and scientists begin to see real-world results from early experiments, it surely won't be long before the transformative 'killer apps' for the technology become a commercial reality.

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