Making sense of a visible quantum object Aaron OConnell
this is a representation of your brain
and your brain can be broken into two
parts there’s the left half which is the
logical side and then the right half
which is the intuitive and so if we add
a scale to measure the aptitude of each
hemisphere then we can plot our brain
and for example this would be somebody
who’s completely logical this would be
someone who’s entirely intuitive so
where would you put your brain on this
scale some of us may have opted for you
know one of these extremes but I think
for most people in the audience your
brain is something like this with a high
aptitude in both hemispheres at the same
time I mean sound like they’re mutually
exclusive or anything you can be logical
and intuitive and so I consider myself
from these people
along with most of the other
experimental quantum physicists you need
a good view of logic to string together
these complex ideas but at the same time
we need to do of intuition to actually
make the experiments work how do we
develop this intuition well we like to
play with stuff so we go out and play
with it and then we see how it acts and
then we develop our intuition from from
there and you know really you do the
same thing so some intuition that you
may have developed over the years is
that one thing is only in one place at a
time
I may even sound weird to think about
one thing being in two different places
at the same time but you weren’t born
with this notion you developed it now I
remember watching a kid playing on a car
stop he was just a toddler and he wasn’t
very good at it and he kept falling over
but I bet playing with this car stopped
time a really valuable lesson and that’s
that large things don’t let you get
right past them and that they stay in
one place and so this is a great
conceptual model to have of the world
unless you’re a particle physicist it’d
be a terrible model for a particle
physicist because well if they don’t
play with car stops they play with these
little little weird particles and when
they play with their particles they
finally do all sorts of really weird
weird
things like they can fly right through
walls or they can be in two different
places at the same time
and so they wrote down all these
observations and they called it the
theory of quantum mechanics and so you
know that’s where physics was at a few
years ago you need a quantum mechanics
to describe little tiny particles but
you didn’t need it to describe the the
large everyday objects around us this
didn’t really sit well with my intuition
and maybe it’s just because I don’t play
with particles very often well I mean I
I play with them sometimes but not very
often and I’ve never seen them I mean
nobody’s ever seen a particle but this
it didn’t sit well with my logical side
either because if everything is made up
of little particles and all the little
particles follow quantum mechanics then
shouldn’t everything just follow quantum
mechanics yeah I don’t see any reason
why it shouldn’t and so I feel a lot
better about the whole thing if we could
somehow show then everyday object also
follows quantum mechanics so a few years
ago I set off to do just that so I made
one this is the first object that you
can see that has been in a mechanical
quantum superposition so we’re looking
at here is a tiny computer chip and you
can sort of see this green dot right in
the middle and that’s this piece of
metal I’m gonna be talking about in a
minute this is a photograph of the
object and here on zoom in a little bit
we’re looking right there in the center
and then here’s a really really big
close-up of the low piece of metal so
we’re looking at it’s a little chunk of
metal and it’s shaped like a diving
board and sticking out over a Ledge and
so I made this thing in nearly the same
way as you make a computer chip I went
to a cleanroom with a fresh silicon
wafer and then I just cranked away at
all the big machines for about a hundred
hours for the last step I had to build
my own machine to make this swimming
pool shaped hole underneath the device
this device has the ability to be in a
quantum superposition but it needs a
little help to do it here let me give
you an analogy you know uncomfortable it
is to be in a crowded elevator I’m
when I’m in an elevator all alone I like
do all sorts of weird things but then
other people get on board and I stopped
doing those things because I don’t want
to bother them or frankly scare them so
quantum mechanics clown mechanics says
that inanimate objects feel the same way
the fellow passengers for inanimate
objects are not just people but it’s
also the light shining on it and the
wind blowing past it and the heat of the
room and so we knew if we wanted to see
this piece of metal behave quantum
mechanically we’re gonna have to kick
out all the other passengers and so
that’s what we did where you turn off
the lights and then we put it in vacuum
and sucked out all the air and then we
cooled it down to just a fraction of a
degree above absolute zero now all alone
in the elevator the little chunk of
metal was free to act however it won it
and so we measured its motion we found
it was moving in really weird ways
instead of just sitting perfectly still
it was vibrating in the way it was
vibrating it was breathing something
like this like expanding and contracting
bellows I mean by giving it a gentle
nudge we were able to make it both
vibrate and not vibrate at the same time
something that’s only allowed with
quantum mechanics so what I’m telling
you here is something truly fantastic
what does it mean for one thing to be
both vibrating and not vibrating at the
same time so let’s think about the atoms
so in one case all the trillions of
atoms that make up that chunk of metal
are just sitting still at the same time
those same atoms are moving up and down
now it’s only at precise times when they
align the rest of the time they’re
delocalised this that means that every
atom is in two different places at the
same time which in turn means the entire
chunk of metal is in two different
places I think this is really cool
really it was worth locking myself in a
clean room to do this for all those
years because check this out the
difference in scale between a single
atom and that chunk of metal is about
the same as a difference between that
chunk of metal and you so if a single
atom can be in two different places at
the same time that chunk of metal can be
in two different places then why not you
I mean this is just my logical side
talking so imagine if you’re in multiple
places at the same time what would that
be like how would your consciousness
handle your body being too localized in
space there’s one more part to the story
is when we warmed it up and we turned on
the lights and looked inside the box we
saw that the piece of metal was still
there in one piece and so you know I had
to develop this new intuition that it
seems like all the objects in the
elevator are really just quantum objects
just crammed into a tiny space you hear
a lot of talk about how climb mechanic
says that everything is all
interconnected well that’s not quite
right it’s actually it’s more than that
it’s deeper it’s at those connections
your connections to all the things
around you literally define who you are
and that’s the profound weirdness of
quantum mechanics thank you
you