Quantum computers
could one day solve
some of the world's toughest problems,
and they’d do this by working completely differently
to a regular computer.
Information is stored in your laptop in bits.
Every bit is either a one or a zero:
up or down.
But quantum computers are made of qubits.
Unlike bits,
qubits can be a mixture of one and zero
at the same time.
Quantum computers
are made of several entangled qubits
with all their states connected together.
But actually building a quantum computer
is a challenge.
In normal computers it’s easy to add more bits,
but for quantum computers
the more qubits you have
the harder it is to add one more.
This makes it tricky to scale up
from a simple quantum computer
to something more powerful.
Another problem is that quantum computers
have to keep their qubits protected.
Too much interference from the outside world
and the entanglement is broken.
But overcoming these challenges
and building a powerful quantum computer
would come with big rewards.
Take searching:
imagine you have a bunch of mixed-up business cards.
How would a computer find the right one?
A normal computer has to look through,
one by one,
until it eventually finds the right card.
But a quantum computer
has a trick up its sleeve.
Because the quantum computer
is in many states at once,
it can search all the cards at once.
After several sweeps it finds the card.
And quantum computers could help tackle
all sorts of other problems,
like modelling protein folding,
and cracking data encryption.
But, even if scientists
can one day build a powerful quantum computer
it probably wouldn't be useful for everyday tasks,
so don't throw away your laptop just yet.
