- After several decades of microchip success,
we are now approaching its physical limitations.
At some point, chips and their transistors
will be closing in on the scale of atoms
which will likely trigger quantum phenomenon.
Electrons which are supposed to flow predictably
will behave unpredictably
and may pass through solid surfaces
or even teleport mysteriously to another part of the chip,
in what's called quantum tunneling.
I'm serious.
In other words, at some point,
it's not going to be possible to miniaturize much further.
However, we won't see the end
of classically computing for some time.
We'll be able to squeeze plenty
of increased performance out of it.
We should also anticipate that it will exist
in concert with any new emerging computing platforms.
Ultimately though, if we're going to enter
the next era of computing to support our future needs,
we'll need a new computing model
that has significantly more processing performance.
- Yeah, I think
it's always hard to tell exactly
when something is going to happen.
You know, we say, you know, five years out
but I think the real thing to think about here
is that quantum computing is coming.
There are enough people like us and Google and IBM
that we have a lot of smart people
and we're spending a lot of money
and it's going to happen.
Could be a couple years.
Could be five years.
Likely within this decade for sure that it'll happen.
And then you have to, like,
take a look at before it happens,
you need to train and develop and have the skills
to be prepared for when it happens.
It's a completely different want to do computing.
It's different than classical computing.
The algorithms are different.
The way that you do computation is different.
You really need to start training now
to be prepared for it
and there are actually some opportunities
where you can learn on a classical computer
about quantum computing to prepare you
for that quantum computer when it does come.
- The difference between classical and quantum computing
can be superficially summarized as follows.
While classical computing is limited
to processing just one of two states at any given time,
a one or a zero, binary bits,
quantum computing leverages
what are called quantum bits, or qubits.
These are an induced property of a subatomic particle
that can represent a one, zero,
both and any value in between,
surprisingly, all at the same time.
It's a quantum phenomenon called superposition.
- So there is a great example in physics experiments
illustrating exactly that point.
It's called Double Slit experiment.
So it's experiment where you have, say, a board
and you have another board with two slits
and you're just sending lights,
light through these two slits.
So if the light was a classical, you know,
if light was a classical object, classical matter,
then depending on, you know, right or left slit,
it would just go through right or left slits, right?
Because classical particle
can be at one position at a time, right?
So it just goes through right or left.
However, quantum mechanics,
in principle, superposition of quantum mechanics,
allows the light to go through both slits at the same time
and therefore, on the background,
you would see a very characteristic pattern.
So, it's not a pattern where you have light
at one point or the other.
It's a light where you have these dark and bright patterns
and these dark and bright patterns
basically indicate we're dealing with quantum matter,
which goes through both of them,
both of the slits at the same time.
And this actual example illustrates the power
of quantum mechanics
because let's imagine I have hundreds of these slits
and let's imagine I will close one of them
and I'll say, which one did I close.
If it were a classical matter,
then you would have to try each slit,
you know, consecutively.
So that would require over a hundred of operations
just to try and see which one is closed, which one is open
but quantum mechanics, and, you know,
this principle of superposition
will provide a unique answer and, you know,
by looking at the pattern on the screen,
one can identify which slit was closed in one shot,
in one measurement.
- Note, however, that when a quantum state must be measured,
it does collapse into a state of one or zero,
something called a wave-function collapse.
Yes, even the final output from a qubit is a binary number.
That's great news because it enables it
to feed into our classical computing architecture.
In quantum mechanics, the idea that a particle can exist
in multiple states until it is measured at a point in time
is called the Copenhagen Interpretation.
It was proposed by Niels Bohr
and Werner Heisenberg in the 1920's.
A famous thought experiment to help grasp this concept
is called Schrodinger's cat,
devised by Austrian physicist Erwin Schrodinger in 1935.
In simple terms, if a cat is placed in a closed box
and small amounts of poison are administered,
it's possible that the cat could be die but equally,
it's possible that there is not enough poison
for the cat to die.
For the observer outside the box
who cannot see the cat,
it can be said that the cat
is theoretically both alive and dead.
It's only when the box is opened
and the cat is observed
that the state of the cat can be determined.
Understanding quantum physics
and its application in quantum computing is complex.
For most of us, we'll never need
to fully understand or grasp some
of the deeper unintuitive concepts.
In fact, even quantum physicists still struggle
with the unusual behavior
of particles and waves at the smallest level.
So let me summarize.
Quantum computing results from eliminating
the binary state constraints of classical computing.
Rather than simply being limited
to a one or a zero in sequence,
quantum computing introduces the possibility
of multiple states processed in parallel.
Right now, we don't know if that could be built.
However, there's growing evidence
that we are headed in that direction.