This Everybody OK can you all hear me.

Who said No hear me now
hey Arjun You made it OK.

You know the traffic OK so.

It's weird to be up
here with my slides but

I'm going to tell you about work
we've been doing I'm smack ticks.

I might be in is this being streamed.

But you can remove stuff.

OK All right.

Sorry no I was going to say
Tama Bensky is retired so

I'm going to try to give even
comprehensible talk right now.

But I want to tell you about things things
that we have been studying about select

ICS metrics are quite beautiful they
are very very soft they're the softest

crystals we know how soft Are they they're
so soft that they can have discriminations

which regular crystals can't have you
can do with foamy stuff OK you know with

foamy squishy stuff you can make it but
regular hard crystals very difficult but

can have discriminations and
they're happy to do it.

Nothing's happening
because it's not on OK So

this is a matic This is called a shear and
texture Sharon is not a person it just

means streak and the thing you know when
you look at a magic is that you see these

black lines in fact that's probably where
the word came from the magic wind right

you have these lines that come together in
four and sometimes they come together into

the background OK So what are you
looking at so this is the set up OK.

We'll do the same or
is it all of old school values OK but

here we have this compact fluorescent
light we send the light through

a polarizer we send it through an analyzer
which is just a polarizer turn

ninety degrees it's going to come up later
because I'm going to call them different

things if I called them both polarizer
you would know I was talking right.

And in between are some models you take
a photograph so we don't know whether or

no molecules there you send light through
the polarizer in the analyzer and you get

nothing because it's polarized light and
the other polarizer is perpendicular to it

the molecules However by refrigerant and
as everyone knows when you have fire for

it materials you get to decompose things
in an ordinary and extraordinary way and

what happens is that the light comes
in it's polarized this way decomposes

along the extraordinary ordinary
directions it goes across they move

at different velocities when they come
back on the other side they add up but

they add up wrong OK they add up wrong and
so they're no longer polarized in this

direction some light gets there the only
time white doesn't get through is when

there is no extraordinary wave or when
there is no ordinary wave and that happens

when the molecules happen to be parallel
to the polarizer the analyzer and what you

see are the black lines the black lines
are all the places where the polarizer

where the molecules are along the
polarizer the analyzer so why do you see

four you see four because there
are defects and there's a defect in

the middle where you don't know which way
the molecules point but as you go around

the defect the molecules have to rotate
by two PIII So once through the polarizer

one through the analyzer one through
the polarizer one through the analyzer for

brushes for black lines and it doesn't
matter what texture you make of it

rotates around by two PIII forwards or
backwards you always get four brushes.

I should say that the true
power of typology is this is

displayed right here on this picture right
because you see here there are places

where two brushes come together this is
the picture taken with a microscope so

it's like microns big right hundred
probably one hundred microns you know it's

at least a micron probably under one
right the molecules are about and

then a meter big right or
as they say in Europe ten extremes OK so.

This is telling me that when you go around
here the molecule comes back to itself

after only going through the polarizer
once and the analyzer once that means that

somehow the phase is indifferent to
knowing whether the molecules are point

up or pointing down I should have done
that the other way plenty of pointing down

OK And so what happens is that means that
just from looking at this picture with

polarizers you can tell that
the the phase has an up down symmetry.

Right and you're looking at this from
a large late scales you don't even have to

have very good off ticks to see that
there's two brushes you can have higher

charge brushes you don't have to just have
four coming out you could have six or

eight or ten or twelve and all you need
to do is count the number of brushes each

brush tells you that the thing is gone
around gone through a motion of pi over

two because one brush is per pair per
polarizer the next one is analyzer so

you can then count it up this would be
like a a three pied effect the four pi

defect the five five effect of a six
by the fact so that's cool they add

in fact they add just like
charges if you read most books.

Do calculations not only do these things
add like charges they even interact like

charges they interact logarithmically
portion of the product of the charges

in two dimensions but
this is the happy exception

most of the crystals are not like this
most of the crystals that we know about

the charges don't add they only have so
neatly and they don't interact

just like electrons right it is it is
a myth to believe that these my gosh.

I'm OK as The Kobayashi Maru I think
right look look look I managed so.

You go around or they say there was
a Martin you were looking right at me.

On the charges those.

Typically add in the charges don't
interact just like electrons it's much

more subtle but we are led into this
comfortable belief because we always

show you pictures of to do
the magic OK OK I'm cool OK.

Now I'm not so cool it's OK So
here is a symmetric and

I'm going to tell you about smacked
expected layered systems they're like they

have layers of like ogres you have these
layers I'm going to describe the layers

the following way I'm going to say that
there's a field five you can think of it

as a potential field like an electric
potential and I'm going to say that

potentials are where the layers are there
was one way or fight was a fight was two

way you know how cool this is because five
equals A In five zero don't intersect.

Right they're not the same point and so
unless fi is six which will be but most of

the time it doesn't intersect and you have
these nice and cool potential surfaces

you could write the density of symmetric
I don't know why it's doing that.

OK you guys know one.

Of them.

Better.

Better fix it OK just in case.

G.'s.

But with this.

Another way.

Of time the blog thing.

You know I'm.

Looking to game.

The system Hear hear.

OK Great OK so.

You can write down the density you can
write down the normal to the surface

because you know the grad five is
perpendicular to the Echo potential

services because we teach
that electrostatics also and

you can write out energy go ahead rate
of energy OK The Energy tells you that

the layers want to be equally spaced this
is the spacing and they don't want to bed.

Now I'm not really that
fascinated by energies

All right there's a theorem
in liquid crystals.

There's a folk hero which is if you give
me a phase I can find a landau theory for

which it's a minimal right so you know
it's not that interesting what I'm trying

to understand is not the ground state of
the smack that I'm trying to understand

all the ground states and how the ground
states are connected together.

So the ground states are things where
the layers are equally spaced and

they don't want to bend.

Now there was a theorem Brian Charron
discovered this there and by

reading OK because it was in some journal
that most of the system read communication

the mathematical physics it was from
before he was born one thousand and one.

So can everybody understand the theorem
I couldn't he said over the theorem but

this is what the theorem
says the theorem says.

If you have things that you would want
to call smack ticks which are things

with layers then things
with layers can have

a negative charge defect you see if I look
at the normal the normal goes around by

minus pi as I go around clock
kind of clockwise by plus five

This one is a defect with minus
two pies this is minus three pies.

This one is boring this is nothing
this is plus high right and

you can see I'm going through a set of
ground states if I just look at this

part here here's a ground state where
the layers are equally spaced and they're

all flat and here's another one here's
another one you slowly go through this.

It's the ground states
to go from here to here.

But when you're done you're in
different ground states and

that is why this is a top logical defect
you can have this too where you have

rotation by plus two piles but
the theorem says you can't keep going

this way you can't have plus two pods you
can't have plus three pot you can't have

plus four but none of it sorry you
can't plus three five you can apply for

pi plus two pies All right so
what's weird is you can't go positive but

you can go as negative as you
like you can keep going down.

Now this is problematic
because most of us learn

about top logical defects by
reading this paper by Maman.

Reviews a modern physics
article an excellent article

which you should not only
download many times we should.

We count downloads it
is important to say so.

What's the story here's a sample
There's the ground state manifold here

is the space of all possible
ground states before it was all

things that were equally spaced and flat
which includes all the translations and

all the rotations of that as well here's
the sample it has defects places where I

can't define the order you take a path you
go around the sample as you measure you

go around you measure what the what point
in the ground state manifold you're in and

it goes around a loop on the ground state
manifold in the ground state manifold is

interesting then the loop
over here grabs the handle

of the ground state manifold and
once a grabs a handle it is impossible for

it to unground the handle smoothly that's
the whole point of typology right and

the whole point is that as you go around

as you let the system of smoothly by
the way it's a classical physics does for

you right classical equations evolve
things smoothly it's impossible to

unwind that handle and so you have
something trapped and there's a charge.

OK So let me prove put our
theorem to you by drawing

a picture then we never do this only
teach electrostatics but we could of.

Here's the X.

Y.
plane I'm just getting two dimensional

symmetric for now two dimensional
spec ticks and here's that thing five

Remember echo potentials a fire going
to tell me where the layers are but

I mean it will draw the graph I have
enough dimensions that I can plot five

because the graph of this function.

And now I take the level setf I call
zero sea level set a good name and

you get this layer and here fight was
one here all the layers so you see

that here you have this green
mountain range and here you have.

The equal height contours of the
topographical map I grew up in the Midwest

so this was a big revelation that you
could have this but how are you Martin.

Everything's minus ten
right OK All right so.

Those are minus three below or
above sea level OK

so so here you have the smack
ticket here the layers and

you realize that a smack Dick is nothing
more than a topographical map and

the cool thing about topographical
maps is that you can always tell

where the tops are and the bottoms you can
see where the tops of mountains are and

where the bottoms of lakes
are because the top of

the mountain is a place where
every way you look is down.

Is that true in the your
mountain in Holland OK All right.

Or it could be the bottom a lake
everywhere you look is OK so.

You go around in a circle
you see here is a top or

a bottom and when you go around it
the normal rotates by plus two pi

that is a plus one defect or a plus two
ply defect all the mountain tops and

all the weight bottoms are plus two
ply defects those that are late bottom

of the mountain top look exactly the same
if I don't put numbers on here I just draw

the contours so weight bottoms don't
cancel mountaintops which my thought

in fact the things that cancel
them are the passes a mountain

passes a place if I look at the normal
the normal if I go around let's see.

If I go around counterclockwise

the direction the normal rotates
around counterclockwise.

Right so

one goes around if I go around to play
clock wise it goes minus two by clockwise.

The passes are exactly
the negative one charges.

In the selected.

So I was put in R.'s theorem true
what happens if you take them out and

try to put another mountain on top of it.

Just a bigger mountain you don't get to
look down on more you don't get to every

direction is still down right around you
you can't get to loops around you there's

still just one closed contour around you
because a mountain top is just a mountain

and a leak underneath
a lake is just a lake.

And a lake on top of a mountain is also
boring just a lake or just a mountain.

What's interesting is bringing
two mountains together and

there's a theorem called the Mountain Pass
there that tells you that if you try to

bring two mountains together you always
have a mountain pass in between and it's

impossible to take these two mountains and
put them right on top of each other and

that's how the charge is conserved because
you say this has a plus one charge and

this has a plus one charge but the problem
is you try to put the plus one charge in

the plus one charge together you trap
of minus one charge you have no choice.

So you can still make a curve I
could do some funny measuring

I got to do it from over here I could
do this and avoid the mountain pass and

I could find that inside the director
field rotates around by four pie but

if I try to make these be the same
point I can't do it because I pull in

the the a pole in the mountain pass
the point is if I look at Point

defects in two dimensions I can't have
anything bigger than plus two pi but I

can have any negative one I like because I
could have it would be an exceptional for

a mountain range but not impossible
I could have twelve mountain tops and

I could have one magic pass that goes
to twelve valleys between the twelve

mountains right there could be one pass
that would be a minus something minus

twenty four five The fact.

Case I could have that.

But I can't add mountains to
mountains you can add passes together

you can't have mountains
if you're a fancy pants.

I'll tell you what that has to do.

With is that this is a that the mountains
and the lakes are the top and

bottom most things you can have
in a two dimensional surface

you can either have something with two
directions that go up or two directions

that go down there's nothing more down
more down pointing or more up pointing.

But a pass.

Is one direction goes down and
one direction goes up and

you can add passes together willy nilly
you can't add things that are top and

bottom things together but
you can add passive Let me show you so

here I'm going to add passes
together here's a mountain pass.

Right there's three directions.

Here's another mountain pass each
one has charge minus one half

I bring them together.

And I get this one a full mountain
pass the charge minus minus one or

I could have this would
be like a mountain ridge.

Right here the two mountain tops the two
peaks of the ends of the ridge and

I can bring these two ridges together and
give myself one single mound.

So I can add these things
together along level sat.

Right so I can add them because this is
by Will some cause the value this is like

life was zero or five was ten or
whatever distance you like you can

bring them together because they're on the
same level set so that's easy addition.

How do you add together.

Two areas that aren't at
the same height remember

expected I don't have to just add
together layers or at the same height

I should be able to move any kind
of defect together that I like.

So if there's the same if they're
at the same height it's easy

if there are different
heights of this lens at zero

This means that one the stache line is a
half the dash lines are always halfway or.

What do you do while you create.

A dislocation and the dislocation pair and

dislocations are made
from discriminations.

And far away this looks exactly
the same as it will be.

Four there's layers going on here I could
add extra layers on either side and

I made a small little region
which is a little different but

it's already not local It's already it's
a region that is not all at one point and

that's kind of the problem I
can't make everything happen and

the thing will point you
have this dislocation pair.

As you go from here to here and
so if you want to add say minus

one half see there's three dark lines
coming out to another minus one half but

there are different values of five
this is Fi equals zero This is five

calls a first what you do is
you make a dislocation pair and

you bring them together and
so look at what happened

this is very strange you have these two
defects which you say are charging minus

one half when you add them together to
tell the charge should be minus one.

But if you count how many
dark lines come out you say

there's too many dark lines coming
out this is a minus to the fact.

Just by counting but in order to bring
these two things together I had to make

this dislocation pair I've
left behind the thing.

So in order to bring defects together
sometimes I have to create new defects.

And the new defects are in
different places so

that's why I can't do everything in
a local way because not to bring a certain

defects together I have to pop
a new defect in the system so.

Here's a story it's the story I just told
you there's this thing called the Morse

index which is the number of
up directions you can go so

you're at a mountain top you can only go
down right there's two directions down and

a lake bottom there's two
directions up that to

a mountain pass there's one
direction up one direction down.

This is called the Morse and that's
telling you how many directions are up or

down you can only add a Morse index
thing to another one that are next

door to each other you can only add
a mountain top to Mountain Pass orally

to a mountain pass you can't add
a mountain to a lake directly.

So these add together but I showed you
the charge of the mountain top is plus one

the charge of the bottom is plus one this
is minus one of course this is also true

I can add a mountaintop
to a mountain pass and

get nothing just like an an A plus
on them I just want to get nothing.

Or a mountain pass to a lake bottom and
I get in the thing.

So you see these alternate charge
these just go down the number or

up in the numbers.

So in two dimensions the reason I
can't have any kind of defect I like

is because I can only add
together things like this

you can add zeros to zero the Tuesday
two you can only add ones to ones.

You can add mountain passes together so

what's going to happen
in three dimensions.

You know in two dimensions I'm going
to give you a rough way of explaining

what we did you look at your point
the fact you count the layers that come

out of it Fike was there fight will ever
layer you like you draw a circle route and

you count how many times is this these
layers intersect the circle zero times

three times four times six
times the charge inside

is one might as the number of times
intersects over two here it's one

here it's minus a half here it's minus
one this is a dumb way or a simple way.

I don't know what the right word thing
is a nice way to see that you can't have

a charge that's bigger than one
because I can't be negative.

And so you have these layers
like that to do in three D..

In three D.

You have a defect and
you surrounded by a sphere and

then you intersect the sphere
with the layers but now

they're not lines they're whole services
that are coming out of these points and so

here is a picture of a plus one defect
a point defect with charge plus one.

It intersects this fear on these two
circles of these two red circles

here is something boring this is
a nothing this is just a layer

intersecting with a sphere and
intersects on one red circle.

This is the charge plus one or minus one.

Defect to zero and see if.

It is not something where it's concentric
fears concentric fears don't work this way

because engineers never intersect this
year but this is a place where the layers

go like this they're like balls appear
balls on the bottom pointing up and

then it goes around like in a Taurus it's
a saddle but it's a three dimensional

saddle multi-dimensional saddle some
direction there's two indirections and

one out direction or
two one in direction into our direction.

And so what we really.

Ised is that you could take this and you
could just abstract it to the spear with

the red circles just like I had the circle
with the intersections of the black lines

here's a sphere it has two circles and
then I can make a graph it turns out

Hilbert did this we found out the other
day and he made graphs but related to

this you have a black dot for each region
on the sphere and you have a red line for

each boundary on the sphere and all
the things you can do all the ways that

surfaces can intersect a sphere correspond
to every possible tree you can draw.

Right and you could have a tree where you
have a red circle inside a red circle that

would be another line here you could have
a third red circle out here that would

just be a branch all possible trees and
the way that you decide what the charge is

you alternate the signs you had plus
one minus one plus one right and

that gives you the charge for
this is charged plus one.

Here I can show you a point charge so
this is concentric fears this would be

the naive thing the hedgehog where
the director feels pointing out you

draw the layers like that here's
the point in the middle these

things never intersect the sphere because
they're concentric fears themselves and

so their charges one because it's
a point defect concentric seers.

And this is the whole tree just a point

nothing is coming out of it doesn't
it there's one region on the sphere.

Here is the one I showed you three
regions charges one those that can have

two different things to charge
one that have different graphs so

in a magic if I tell you the charges
plus one the charges plus one and

every plus one charges homotopic to every
other possible and charge in this MC tick

these two plus one charges are different
you can't go from one to the other so

what's cool is a symmetric then in two
dimensions the selected had fewer D..

Facts in the magic in three dimensions
this Mexican's more defects that

the charge is enough to tell you what's
going on you can have point charted and

you can have even more here's one where
the charges zero there are three layers

there's this cone and this cone and
this flat plane the charges zero that's

the graph Here's one where the charges two
and here's the graph notice that this has

four region then this has four regions but
they're connected in different ways.

So the tree doesn't tell you enough the
tree doesn't give you all the information

nor does the charge so the effects and

smack ticks are actually more subtle
they actually are there's a there's

a refinement of them beyond just telling
me their top logical charge like in that

if you can add them together Thomas shown
is really good at drawing pictures but

you know here you can add together two
point defects that are on the same surface

this is adding along level sets
you can add them together.

You can also add was together that are on
different level sets to do that you have

to make a dislocation you actually have
to poke a hole in this middle surface

you have to be able to connect
this cone to this cone

through this intermediate surface this is
like five holes they're zero one two and

one make you connect so
I have to cut a hole.

You notice that in order to do this
I have to introduce a wind defect.

So a weird thing about smack
ticks is that in order to

have selected to do anything interesting
if you don't want them to be sterile

you have to introduce line defects in it.

And say the highs Emberg model of the X.

What in the in the in a magnet in a model
of a magnet you can just have point

effects you don't have to have one
that you want to have wind effects in

the Maddux can have them but a smacked
it forces you to have it if you want

this method to do anything interesting
it has to have wind effect so

you can have a boring smack
dick which it stays and does.

And it does or you could have one that
stain Amec with a defect mix around but

then you have port wine defect and so

it really requires us to
classify wine the fat and

we did and it's a little more complicated
but not a lot more complicated is

that instead of wrapping a sphere around
the line you wrap a cylinder around the Y.

which means you can have one region and
one boundary you could have a graph like

this so it's a it's a it's not a tree it's
a something with one loop and there's

different graphs it's interesting but not
that interesting I mean it's interesting

is interesting it's come do it to do
it completely you have to have it

it also means that even if you think
that you have a nice oriented smack tick

where the layers all with where
the where the directions of

the layers are all perfectly well defined
you don't have the cinematic symmetry

you are forced to have half charged
effects if you want to have any dynamic.

So for instance here's an experiment.

If you have a two D.

smack tick a regular to be smacked at.

You have all the Bernard convection cells
so you have these roles in the Rolls or

go in opposite directions next to each
other that's a regular to be symmetric

because you can bend those things around
and you can have a half charged effect but

if you had lines or defects that came from
if you had stripes that were in a coup

itself so you have an inner cylinder and
outer cylinder those roles

are always going in the same direction
they can't bend around and turn around so

rolls in a coup at solved are going to
be different than their dynamics and

going to be very different than roles
in say a road Benard convection cells.

So.

By.

You next speaker you know.

All right so.

I'm going to give you an application
of what we did right so

here's this very old picture it's in
French it makes it even harder to read

OK but this is a picture of a.

A defect in a smack tic it's
actually a screw dislocation and

a smack tick it connects layers around and

he woke away and Claymont pointed out that
you can actually decompose it into to.

Discrimination.

To discrimination was the charge one
half because as you go around right.

I wish I had a boy I'm not going
to deface your thing that but

you have you have something like
this here the preview points and

here you have the layers and then you
rotate it and you go around this way.

And that gives you the structure and
here these two discrimination lines but

the charge of both those this
commission lines is plus a half and

you know anybody who grew up in the area
that I grew up knows that dislocations

are not made out of discriminations
of the same charge but this

locations are made out of discrimination
dipoles So here you have a plus a what

a plus what happened in minus one half
discrimination making dislocation.

But here I have two plus a halves making
a dislocation and we never stand how

to connect those things together
in fact I remember city enough and

I had the amp room once it wasn't
down it was hot with the bed and

Brian Chan and Gary thousand and are we
convinced ourselves as a possible way but

we were wrong but it was because we were
in Princeton OK It turns out there's a way

to do it you can do it but to do it you
have to squish it and make this plus

one have to factor into a pair with
a minus one have to figure and I know this

picture is completely incomprehensible
Let me show you a different picture.

Here on the top I have something
that looks like plus one half

goes around the director rotates
around by pi on the bottom

it's something where the director
rotates around by minus Pod.

And in a magic These are exactly
the same thing in a magic

rotating by Plus pyro to my mind aspire
the same thing in three dimensions

because you can escape
into the third dimension.

I remind you that that's true so here is
the magic gravity manifold R.P. two Here

is a structure where all the molecules
are rotating around this is plus one half

now I smoothly deformed the texture and
they're rotating up into the X.

into the Z.

direction and I come back around and
now I have a path that still goes from

this point to this point that used to go
around this equator the center the equator

now go to that end of the equator and
they have a minus one half show you again

you go from plus one half
to minus one half smoothly.

In a magic you can't
do that must make them

in a smack tick you have
to do it at a point.

Because can't do that thing of
rotating out into the third dimension

you can go from my
IF THEY HAVE TO plus a half but

you have to do it at a single point where
you just add this like boat to the set

of layers and quite abruptly It
means that a cover experimentalists

could prepare a cell with a plus
one half the fact on one side and

a minus one half defect on the other side
you know you draw down to the surface

put a smack tick in there and they'll be
a wind effect that connects them with

a point City on it they should be able
to move right by doing something clever

I don't know how you could move it
right you do something some kind of for

recess you do you something you come
up with something clever OK you know

you you rotate it you put seven up in
the space shuttle I'm sure that we

are no spatial if you send it to the space
station is there still a space station.

One of just follow the sky
right let me know.

In a space it should
just fall out of the sky.

Yeah no no there was a space station
they thought of the sky no one was in it

because of the way it was
the satellite was in it

OK it was orbiting the Earth though.

So let me tell you where we're going so
you know this classification

of defects point defects
is hard because the math.

Partly because you could write down
what you're supposed to do but

no one's ever calculated it right and
we don't know how to calculate things so

we have to make up our own things but the
problem is or the problem is how do you

cross a five defects in general and look
at crystals so they're pneumatic everyone

knows how do Magic's their smack ticks
I think we kind of have to handle and

smacked it but the real challenge is not
selected the real challenge is called.

Let me tell you about Lisa trans work and

with that Lisa Tran just defended
her thesis that she's Dr trained so

we're going to Bryn Mawr any year so
she's professor trained OK she made

this she made this in a laboratory
OK this is not a simulation

this is a coast there are shelf there's
a shell there's water on the inside and

there's water on the outside there's
some delicious surfactant to hold

the whole thing together and in between
it's Coast Eric with the crystal and

the beauty of the surf act it is now it is
a surf act and hold the things together

there surfactant actually changes the
anchoring direction of the molecules so

I'll remind you what to call a stereo
because this is a soft matter school so

you guys should all know right
coast to coast Erik's or

systems where the molecules
rotate to go around.

And helix the helix Lee.

It turns out the surfactant like that for

the molecules to be parallel pandered
to perpendicular to the surface.

Revenue you a service doesn't work how
can I be perpendicular to the sky and

also do this.

So I can.

So what it does it does this good and
then the.

Right it makes these
very fast motions through

the rotation so it manages to rotate but
you can change how much

it rotates by changing how much
the fact that there is by change

you is there a fact in concentration you
can change how hard it is to rotate and

how hard how how how and phatic likes
to point normal to the surface.

And because there's water on the outside
Lisa just changes it by washing

away surfactant and here the surfactants
going away you have straight stripes and

then when it's all done this or
fact is gone and

the molecules actually
tangent to the surface

now those are pretty pictures right we
did this with the recent Lopez Leon.

But.

I guess a this one to go.

Ahead I don't know where Peter is.

With that.

Three three minute.

Well let's just go very pretty We don't
have any idea this takes days to unwind or

hours we have no idea why it organise
themselves so that we can look at it so

nicely but every last one of them do right
we start them they start in some random

direction and it rotates so we can watch
it right as not thermal because we

turn the light off in between pictures we
don't think so right could be gravity.

Which is why we have to
do it up in the space.

But I want to show you
a picture I can find.

No I can't

find it right now it's OK Let me
just tell you what this is good for.

So Lisa working with
Martin Haas figured out.

That in fact the surf acted does not
uniformly smear itself across the surface

of the surf act it actually face separates
and goes with the straight stuff.

And she knew that by putting forth a sheaf
Leslie labeled some of the some of

the scene for us and labeled the
surfactant you could see where it's at but

then what she did is she took
coal oil it's interesting that

they're right now they're not interesting
they're probably you know silica but

they could be interesting they could
be cadmium selenite quantum dots right.

She functionalize them and surfactant and
then they sat on the layers and

you can cross-link them you can cross-link
them in place so you can actually

stop this pattern whatever you want
because these are all equilibrium or

quasi equilibrium you could stop
right now you could wash in

wash out the old washing the noose or
fact and that has quantum dots on it.

And then you can put a rise in place so

you can make patterns you can
make resonators is our hope.

To order you can have lots of little
resonators if you wait long enough you can

have one giant resonator OK so we can
actually now make patterns structures and

we have control over the pattern we even
understand how to get them I should say

this is to reset the main point to
reset makes this point quite eloquently

the beauty about shells compared to
drops is that a shell is the best

thing you can do to get a fairly suspended
surface because you can control the inside

anchoring and the outside a Korean
separately and we can do that

because we can change is affecting
concentration on the outside dynamically

we can set the concentration on the inside
when we start and then we can use salt

to swell the whole shell which changes
the concentration on the inside so

we can change everything we can change
the inside on the outside there.

Also a temperature dependence
which Teresa's group discovered So

there's many knobs you can turn to
actually change what the patterns

are you can have these
patterns that are hexagons and

pentagons you can have more complicated
patterns if you mess with the insides.

I'm going to leave you with pictures
of my three collaborators hell how.

Each and and

Thomas shown is about to leave us in the
breast stuff so thank you for attention.