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