# What is Quantum Computing?¶ In the previous section, we learnt about the interesting and very strange properties of quantum objects which make them different from everything we know about in our classical world.   The computers that we are on right now makes use of classical Physics and run on classical behaviours.

You may have heard about ‘bits’ before.  A bit is the basic unit of information in anything pertaining to computing and digital technologies.   A bit can be 0 which is ‘off’ or 1 which is ‘on’.

When we piece together many bits, we get binary code. Binary code is the natural language of computers. Everything that we can and will do on a classical computer all gets broken down into binary code.  This is how computers work.

However, you can imagine that the bits for our computers can only do classical things.   They can only ever be “on” or “off”.

But if we were to make our bits quantum, that would mean that our bits can be in superposition, or show interference, and even become entangled. We expect that we would be able to do so much more with quantum bits, and this is the justification for Quantum Computing.

Let’s summarize.

• Quantum Computing is when we do computation which makes use of quantum behaviour instead of classical behaviour.

• To do Quantum Computing, we need quantum systems in order to access the interesting quantum behaviours.

• Unlike classical Computing which uses bits, Quantum Computing uses quantum bits or qubits for short.

• Qubits are interesting because instead of simply being in a state of 0 or 1 like classical bits, they can be both 0 and 1 at the same time!

# Short Quiz¶

Can a qubit be 55% 0 and 45% 1 ?