What is Quantum Computing?

Can you imagine your life without your computer? In today’s digital world we
seem to use these devices to help us accomplish so many tasks that going
back to a time before laptops seems ridiculous.


However, while our computers today are great for completing run-of-the-mill
tasks, there are many more complex problems in the world that these
machines will struggle to solve. Once a problem becomes a certain size and
complexity, traditional machines simply don’t have enough computational
power to tackle them. For this reason, it is expected that we will rely on
quantum computers to solve some of the world’s most complex issues.


How is quantum computing different to normal computing?

Any ordinary computer chip that you will use today uses ‘bits’ to function.
These are like tiny switches, that can either be in the off position –
represented by a zero – or in the on position – represented by a one. Every
app you use, website you visit, and photograph you take is made up of
millions of these bits in some combination of ones and zeroes. This is great
for everyday life but when we are crunching calculations, traditional
computers aren’t great at handling uncertainty – not everything can be
represented by a state that is either on or off.

The key characteristic of quantum computing is that with these devices we
can create states called ‘quibits’ that can be both on and off at the same
time, or somewhere on a spectrum between the two. Put more simply, for
scientists to properly simulate scientific situations, the calculations they
make on a computer must be able to handle uncertainty in the way
that traditional, and even supercomputers can’t.

A great example of this is flipping a coin, with coin toss you can either land on
heads or tails, right? But what if you’re spinning the coin? Then the coin has
the potential to be either. This state of uncertainty is something a quantum
computer can hold and use to determine how things work.


How does their computational power differ?


To put this idea of computational power and processing superiority in
perspective, Fugaku, the world’s fastest supercomputer is over 1,000 times
faster
 than a regular computer. Indeed, due to their speed we are already
using supercomputers to help discover advances in modern medicines, for
example towards finding cures for cancer and coronavirus.


While this in and of itself might seem impressive, quantum computers are
even more powerful than super computers, with Google claiming in 2019
that its Sycamore quantum processor was more than a billion times faster at
solving problems than a supercomputer.


How are we using quantum computers?


Today, quantum processors are used by researchers from all over the world
to test out algorithms for applications in a variety of fields. Most of the big
breakthroughs so far have been in controlled settings or using problems that
we already know the answer to but that the quantum computer worked out
at a record speed.

However, these computers may soon be able to spur the development of
new breakthroughs in science, discovering materials to make more efficient
devices and structures like more powerful solar panels, as well as identifying
patterns about traffic etc. in order to help quickly direct resources to
where they are needed, such as ambulances.


Finally, it is worth noting that these devices are incredibly sensitive to
interference meaning they have high error rates. To try and mitigate this they
have to be kept in a state of isolation from all forms of electrical currents and
they must be cooled down close to absolute zero to function.

Once they become more reliable, they’ll mostly be used by academics and
businesses, who will probably access them remotely. It’s already possible
to use IBM’s quantum computer via its website – you can even play a card
game with it.

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