We were not allowed coffee or
food in the in the hall so then we

won't do that again but you're away drinks
and beer I take it OK so what I'm good.

At this afternoon is first of all a bit
old Chris National Laboratory because

I'm sure some of.

The laboratory is and what it does and
then about neutrons Oakridge National Lab

then we'll give some examples of science
and engineering applications in future

directions and I'm going to finish off
with an example current work on quantum

leap because that's something that Martin
suggested I might want to talk about so.

Anyway first of all
Chris National Laboratory.

Book Club oratory was a major lab that
was set up with the holy of developing

the bomb during the Second World War or
peace that's famously that was.

And it had the world's first continuous
operating nuclear actor the Clinton pile

it also developed the chemical processing
techniques to separate plutonium

from a ready to fuel so
it was absolutely juicing the weapon.

Actually this reactor that was.

Was immediately used for other purposes
as well and I'm director now of all and

then to the shore wall and center is named
after Chris Christie cliff children and

earlier in the wall and
she won the Nobel Prize for

developing neutron scattering which she
did in all Krige and arest wall and

actually was his mentor there but
one's work actually done under.

The for sure.

And actually the early
experiments were classified and

only declassified in the ninety's.

Were about price could be awarded so
to honor his contribution we include

both their names in the rename and
the Joint Institute.

Of.

So or Chris that I'm still leading science
and engineering laboratory produces.

Provides a vital asset for the nation in
terms of key capabilities for science.

And ology A C I want to have two in dollar
budget there's nearly five thousand

employees there it's got the nation's
largest materials research portfolio and

we have over three thousand
guests coming in annually.

It's got forefront computing capabilities
so how the world's most powerful

Internet China's moved ahead but we'll
also have the world's powerful computer

again from next year when we have
the summit supercomputer coming in as

the world's most intense neutron source
and a world class research reactor as well

we manage not just the neutron program but
many other things.

To project to next
the scale computing to so

it's a diversion of oratory
that has a whole set

of really special capabilities and
it's about three hours drive from here.

So a lot of the research is
is really driven by the part

of energy interests but as part of the
remit the lab we run facilities that all

researchers can actually access and
use so building technology it's research

integration into a carbon fiber technology
facility center for nanotechnology so

that if is material science manufacturing
demonstration facility with three D.

printed cars and things there's
a huge amount of work being done

in advanced manufacturing
National Transport Research Center.

And of course the leadership
computing facilities and

neutrals work with all of those and so we
integrate those capabilities together and

I think it's actually
a unique opportunity.

For doing science so
some of you I think a Ph D.

students if you have the opportunity
to come to a lab it can be Agree

way that you can actually learn about
completely different parts of science and

also how you can use them in concert for
your research to.

OK so about the future of programming
Oakridge we have to really special neutron

sources the first is
a science a top reactor.

Which actually dates from the sixty's
although it's an old reactor

of the ultimate reactor because it
was built in a really special way is

the the first compact core reactor so
as an extremely high neutron

flux the reason it was built like that
was because to create a number of really

important isotopes you need to double
capture neutrons so they put that to

the limits to produce the highest possible
flux there to do these really special.

Elements of the splish a neutron source
is the world's most part elevator based

neutron source it's a technological
tour de force and it's been running for

years incidentally we put
a new cold source and

new instrumentation in the high for
die still reactor but to go to so

really in its current form you transcends
the Oakridge is only ten years old and

a lot of that time has been
building the capabilities are.

Waiting to see the end of the program and
the science actually really happening.

So about heifer's A C.

is it's a really special reactor and
it provides us with twelve neutron

scattering beam lines it doesn't
just do that it produces.

Eighty percent of the world's supply
in California which is critical for

cancer treatment it
produces the plutonium for

deep space exploration it's used for
radiation experiments for

fusion reactors and also for
next gen fission reactors and

it was involved in producing these four
new elements for the period table so

as you know probably at the end of
last year to perform the element.

Cited to appear at table one was called
Tennesseean and it was in honor of

the contribution that the reactor made and
in producing these elements.

There's an ass is the world's
most intense beams of bronze

it produces them by
finding really intense.

Themes of proton American retarget And
then what happens is the protons

are captured the energies and neutrons
essentially evaporate of the nuclei.

And so they come flying out and

we then moderate down using
conscious materials ninety usable.

Energy skills and that gives us big
bar of neutrons that we can use

parents why it's really
important to produce a pulse of

burst of neutrons is because
we can then use the timing.

Trance to arrive instrument provide
us with the energy information

the way fetter and scat and
energy transfers and

scattering experiments so we don't
have energy resolve the Tatars for

neutrons which just capture the neutron
we notified attention to are not and

so we need to work at the kinematic and
we.

In the scattering and.

For doing that we didn't do this before
because reconstructing the billions and

billions of events that you have
to do on very large arrays of

positions as detectors was computationally
to challenging years before so

in a way the spoliation source
new trends are growing up

with computational tat means and
so us being colocated with all

the mathematicians in the supercomputing
capabilities is really important for

us to realize the potential
of these new math that's.

The.

Problem.

As soon as the world's best
neutron source is actually

put the world's best neutrino sources for
help so it's three weeks ago.

It's kind of this amazing new detector
which is the team kilograms and

actually detected the nutrient the
nutrients being produced by the target as

well know wise S.N.'s the world's best
neutrino sources Well well it's all for

ninety nine percent of the time so you're
measuring the bank and really really well

and you're able to discriminate these
neutrino events so this is a amazing.

New technology for neutrino detectors
that's that's just come out.

So since the ten years of getting the the
police and the cold source up at neutral.

We've had a scientific accomplishments
I'll just run through these to give you

an idea where new trends fit in as part
of the experimental capabilities we have

Newton's overall kind of
part of the big three.

Scattering.

We have photons electrons and
neutrons and protons and

electrons of course we can produce in
the lab or we go to synchrotron source.

But neutrons are really hard to
produce as you've just seen.

But neutrons photons and electrons
are all distinct from each other and

give you a different view of what's
actually happening in matter

what special but neutrons is first of all.

They're not interacting with electrons as
such the either interact directly with

the magnetic moment on the electrons so
they're giving us direct

view of the magnetism with a really simple
matrix element which means that we can

compare with computation well or
they're interacting with the nucleus and

so they relate very very well to D.F.T.
calculations.

The are very light elements and
you complete games hydrogen for

example is nearly invisible
to electronics and photons.

And you complete games of isotope
substitution to essentially highlight

different parts of materials if
you want to see what's going on.

Another thing is the kid ticks off the
neutron means that their wavelengths and

energies match very well
quasi particles and

materials and that means we can not
just a fraction of materials we can also

look at the whole dynamics of what's
going on and of course if you are in for

example quantum mechanics you
want to get the spatial and

the energy dependence
of what's going on so

if you if you think about
electrons in a box for example.

See what you want to look at a particle in
a box if you want understand what's going

on that you want to somehow understand
what's happening spatially and

as we function but also what's happening
energetically with the different

eigenstates as well and then we need to
answer able to give you exactly that kinds

of information in on sample
quantum systems because

they're giving us full frequency we
have better information on the system so

they're probing the ensemble behavior
system that's been critical for

understanding for example new
superconductors like the iron based

superconductors for for
thermal transport and thermal that tricks

we can reconstruct from the line with
the full on switch of the quanta kind

the heat from those you can reconstruct
what the thermal conductivity is

actually are in the material if you
just try to measure thermal conductivity

you're sexually measure the the things
are stopping the flow of.

You're just you're just measuring
the breaks in the content of the T.

whereas with this technique you're
actually seeing the detailed scattering

process of the quanta themselves.

Biomass and bio energy neutrons
are being critical for understanding.

An example later.

We can work in extreme conditions this is

a levity to where we are taking up to
extremely high temperatures and then.

The formation of glasses or solids are of.

But by by reducing the heat you can
do these really difficult experiments

all in situ because neutrons
can penetrate through very

complex sample environments the weakly
interacting with matter and so

you can focus them in on your sample and
get them through a lot of other material.

Quantum states and
frustrated magnets to see and

probe very complex quantum states and
you can get a picture of what's happening

Tallis ninety percent of the tallis
this is actually done by Hydra.

So how do you see it you need
this probe to see hydrogen.

Energy storage again lithium so.

Difficult to see.

Thin film and had to structure soft matter
with neutrons we can substitute for

deteriorate we can make large amounts
of organic matter essentially

disappear from the experiment highly
only the bit that we're interested in

that means you can very complex feces and
very complex physics.

And it so that's why what neutrons.

Where they fit in the wall of the for
experimental science.

So here's a few kind of examples
of quickly run through this is.

A top logical insulator and this top
logical insulators it was dismissal and

I don't know European or European supplied
film and this was looking to functionalize

ation of the magnetic of the magnetic
layer with a top logical insulator.

These are in varied layers that
you can go through buried layers

soft Actually this is
essentially not possible to do.

And so you can probe right in actually
the key thing was this was done by an MIT

group for your competitors is that.

I keep it of MIT for
not coming here I don't know.

But here Georgia Tech's get inventor than
than MIT in all respects and yeah and so.

So actually this was really surprising
using polarized neutral reflect

Tom a tree.

It turned out the way the interface
between the magnet and

the top logical answer was that it was
nothing like what was there to be.

Proposed.

What the final outcome of this but it was
the penetration depth was much further

than was expected and
one of course the critical questions and

top logical insulators in the functional
as well as home port are correlations and

realistic things in the system
actually going to be.

Here's.

An experiment on a material
strong sentiment.

This is a top logical semi mantle so this
is actually a magnetic vial semi mantle.

So of magnetic pulse a matter of direct

that you get in graphene are kind
of ripped apart into the chiral.

Kind of cones that have
spin Kyra Lety in them for

the spins are kind of pointing
out from the cones themselves so

that the wave of the spin gets lots of the
wave factor of the electrons in the battle

and one of the big quest
has been to find magnetic

semi mantles because then you know that
the possibility is there to manipulate

these top logical electron systems
with a parameter that you could.

Like magnetism and so the role that the
neutrons please as the are pairs shows.

The arcs so-called arc behaviors which
is expected for this top logical state.

With my magic fields in it magnet live you
can you can see the quantum oscillate.

Or do but
to see the actual magnetism being it

you did neutrons because they know when
they can scatter off the magnetic.

The act of the magnetic structure and

you can reconstruct what
the magnetic structure is and

there are certain symmetries that you
require to have this behavior and that's.

Yeah actually see so in sentient
experiments to see the magnetic origin you

need to to run things with this and

with this in Carley with
sentimental properties.

One of the things that's
really exciting just now

in the neutron field is
the link to computation.

Or high level computational simulations
are able to learn a lot by proofing

against expect and then we use them for
further design of material so thermal

checks are a big target for Department
of Energy for obvious reasons so.

Based approaches that would have dramatic
effects on cooling technologies or

energy recovery from from heat recovery so
we've been doing a lot of work for

looking at the connecting the thermal
transport behavior which impedes

the performance of thermal that tricks and
understand how to block the thermal

transport by the hearing the photons and
cause.

Maintain the conduct of properties
that you're needing for family and

that's actually been
extremely successful and

that's been driven by
a delirious group into.

Our city and I.

Soft matter there's a lot of work actually

understanding soft matter obviously
from the reason I gave before but

one of the critical things as we're able
to look at the dynamics and soft map.

To prove the time skills of people second
to those that things are happening on.

This experiment here was actually
one taluka I in conductivity and

the way that the polymers were
behaving and those were behaving in a.

System.

OK so here's a bit about bio fuel.

All right so here's some.

But so but it was again was a big
target for has been a big target for

Department of Energy So
the critical thing with biofuels

is you're wanting to grow plants and
then extract ethanol for for

obviously use in your craft or
whatever you know.

Switchgrass is about five times
more productive in terms of energy

project here than than corn is but
it's extremely hard to extract the bio

ethanol from so
it's been a big target of the bio.

Bio fuels.

Efforts And so what has been done is.

Experiments have been done to look at
the end Matic behaviors to the way you get

bio ethanol from these and
see what inside the switchgrass think so

this is a high performance
computer simulation from time to.

And you can see it's made up of
crystalline cell you will find buyers and

then you get these heavy Cellulose Fibers
and then link in there and

what you need is you need to get
the enzymes in to the cellulose

to then break them down so the experiment
that been done to be duking at the ends

aims and understanding how the they're
doing the catalytic reaction but

farther how the process thing.

Actually operates so
that we can by all reengineer switchgrass

to perform much better so why actually
happens is that you heat this thing.

Up and

then you find when you cool it back down
you put the enzymes in the work better.

And so the question was why and the reason
it turns out it was essentially this.

And then you can see was and

this was all done by doing
careful to treat experiments on.

We happened.

And that gave the pathway forward.

How to reengineer switchgrass essentially
Switchgrass is being bio reengineered to

then loosen up this matrix by having less
of the same cellulose production in it so

the reason that this thing was very costly
wasn't just the energy cost of the heating

all the stuff up before processing it it
was you were losing ninety percent of your

enzyme which was getting stuck in all
this meat tricks before and making this

prohibitively costly to do so that then
feeds back into bio reengineering and.

So.

We can even will live on work
on living cells as well and

using genetic engineering techniques.

It's been possible to do the following
kinds of experiments where in actual life

cells by doing exchange of to Tyrian
hydrogen effectively been possible to

highlight make essentially the whole cell
invisible by choosing the to tear and

hydrogen ratios carefully we can make
the sail essentially disappear to neutrons

except for
the key part that we want to study.

And brain.

And.

Using these these bacteria.

That's been possible to do experiments
in of life membranes in living cells and

sure the nano scale rafting actually
occurs the nano scale rafting has been one

of these big speculated on this
in biology is that you have.

Groupings of of it's within membranes at

the nano scale and those provide cites for

active proteins to go and then the effect
to functionalize ation of the proteins.

In the memory.

Operation of membranes the major things
in your cells that we really need to

understand proteins and membrane
No one thing I should point out is

electron microscopy these cryo
yam even the neutron results of

this living memory works if the there's a
substantial difference between the actual

measured thickness with neutrons in the
real part to you and what you get when you

cool this thing down you freeze it
you do electron microscopy to it so

the actions are seen the real lifing
behavior and that's that's critical.

Here's.

An example where competition or more
when using tense the functional theory.

Is opened up by doing
the neutral experiment so

we can measure in about thirty seconds
nickel spectra using neutron method so

rather than using light you can use
neutrons for chemical spectroscopy but

they're uniquely sensitive to
hydrogen some particular and

this experiment here was actually
looking at binding and it was one where.

You know they were using.

Metal got it free marks.

The researchers from this is from the Max
Planck Institute in Germany were looking

at ways of separating hydrogen and
tritium from each other so for

doing cleanup for them for.

Being.

Rigid nuclei for
doing the RAM separation and what.

Was learned here was exactly the binding
with the binding worked between the metal

going free American the and the hydrogen
we didn't want to run it with tritium so

no one wants to do the trick
him experiments but

by very exactly proofing the X.

the computation.

Then.

What would be expected so

you could do inform design of
the method on it frameworks for.

The cleanup and

that some more that we're increasingly
doing is proofing modeling up to.

And then using that modeling for
refining and

engineering essentially the final system.

Another place where there's
a lot of impact going on and

I don't have a lot of the latest.

Videos of this is of course on on.

On additive manufacturing so
many fashion different

manufacturing process is a kind
of revolutionised we can meet.

Challenges So one of the things with.

Hundreds of manufacturing
is that introduces.

That introduces huge and strains in the
material but it has huge payoffs as well

so here's a tire buy and believe that
energy efficiency of your jet engine

is determined by the temperature
it can actually operate on.

The dynamics basically so

the higher you can get the jet
engine to work out the fish and.

We have to make it extremely
easy to want to follow the sky.

And the way it work it really high
temperatures is by having channels

right through things which you can only
do by additive manufacturing and so

what we're able to do is so we can look at
the difference between CAD drawings and

actually what's produce than that where
you can model exactly the contractions and

stresses are built up in the material and
use the neutrons to directly see

all the texture in the material
all the stresses in it as well and

the internal cracking that's going on so
it's a killer application and

it's a killer technique to actually
understand how to get this

kind of technology in
automotive an aerospace now.

So that's something that
we're in that really hard on.

At the moment OK so.

Then you try and neutral science is
changing really rapidly it's going through

the biggest transitional thing can at
least forty years because there's a next

generation of sources coming along that
have game changing performance which will

provide us with instrument one hundred
thousand times better than we have

at the moment in the cold
neutron regime so.

That will provide us with completely
new key for me to scale materials for

Quanta materials of matter
Europeans are already active

thing a next generation you
Transource a so-called Europe.

And we have an answer for
source that will that will match or.

Compete if inspiration source to
be cited at Oakridge National But

second target stations.

Open up a whole range of science
neutrons are absolutely.

Flux because we produce
them through nuclear

sees the really really difficult
to increase in the flood

zone some really smart technologies
this big step change in performance and

that will be the biggest step change in
at least two generations in neutrons so

that's a big deal for us just now and
we've got quite far with our plants.

To deal we have went to assume so-called
C D one review very successfully for

the first part of building the second type
station which is the proton power upgrade

which readers are accelerator complex
ready to host future target and.

Experiment ensemble.

So we have three thousand
users a year coming in

anyone here that wants to
use neutrons can come.

And do that you just write a proposal in
fact what you do is if you don't nothing

about it you contact me or one person
just the hey can I do this and then.

Exploring ways in which the experiments
can be run that results in proposals if

it's if it's good enough the independent
selection so we have an independent.

Coming in judging it scientifically that.

Time.

We also have work spaces and so
on that if you want to come up and

visit we can host you for a while you can
look at what you can do this goes all

the way to having dedicated lab space for
longer term projects so

I know for example there's interest
the soft matter here are quantum materials

if reasons want to build up we have
got a platform for engagement.

Of universities with that and that's
through a wall and center that currently

Direct which is right on site and
right beside the spot Leeson source and

the nanotech center so
it's an ideal location.

OK so I want to move on to
some quantum science stuff so

this is what Martin wanted
to talk about or so.

What people worked at all kinds of
different things right so OK so I should

tend to give some background as to what
the physics problem is far and then tell

you where we're at just the first of all
see this is about quantum spin liquids and

this huge interest in topple call
quantum states at the moment.

And I see that would benefit the.

Understanding this whole thing.

There's new ideas coming into physics
they're challenging the experiments

the way we approach them is different
from what we've traditionally done so

it's really great because it's
making us think a lot of.

The basic physics when we
what is the challenge.

A challenge just a.

It's to understand how we can get
urgent top logical quantum behavior

in quantum systems we didn't have that and
the proposition by was.

About ten years ago was that in
a very simple honeycomb lattice

you could get a really bizarre quantum
state of matter which was close to

the so-called toric code which is an error
correction called for quantum computing.

So this loop is a super simple lattice
honeycomb lattice The only problem with

that was the most unphysical looking
set of exchange couplings possible

you know in real we have
a huge range of spin

that works just sitting there essentially
when ever you got a transition metal.

In a crystal structure it will have
a magnetic moment usually because paired

electrons and the wave functions
of that self elections will will

overlap somehow with the neighbors and
that will cause exchange interactions and

so nearly all magnetic material nearly
all star systems consisting of.

Metallic ions with one predilections
will behave as spin networks.

The problem with this spin network that
cattail have was proposing was that it had

icing tiny.

Couplings ice in tech companies
of the simplest kind of

couplings that we hear about.

It's and so while that's great was it was
there any kind of eyes in type coupling

it was a really weird one where.

You wanted it to be blown directional so
depending on what Bond direction you went

in the honeycomb lattice you
wanted it to be just the X..

Cartesian coordinates of the spin for one
wife or another and said for the other.

Sounds abstract it is it's
a completely artificial Hamilton.

Brilliant reasons which
you'll see later the talk.

But OK so this is the honeycomb Atlas and

it's actually essential the frustrated
lattice because the spin doesn't know all

which partner issued a line worth right so
it's frustrated and

Kitty have said this thing will go
into a really special quantum state

over all the this over the network and
the question was could we realize it.

For.

The question of.

Wood or what it was if you saw it right so
could hear its thing was completely

abstract and uses a series of mathematical
tricks to show this proposition and

was absolutely physically or

pick I don't know Martin if you understood
it at first but I mean it's physically

almost without content mathematically
full of content Yeah so.

You could go no guidelines for
what you actually expecting to.

Snow.

A step for actually.

Your hands can all of these piers

calculated what the excitation spectrum
would look like in this the dynamics and

so the elucidated for
the dynamics would look like an it and

it's not that unexpected is some kind
of it's broadened in Wave factor and

it forms at some some broad and
kind of signature which has some special

features in it so it's a kind of
liquid type behavior that you see.

Or expected to see and so it has special
characteristics that are different from

what you normally expect but
that was the prediction.

And then the other breakthrough that
happened was actually realizing

that this was not a completely
impossible Hamiltonian after all.

But after some very clever.

Thinking about spin or

brick pulling in materials that was
realized that actually you could get this.

Relatively common if
you knew where to loot.

It so the search was on to explore and

find as many materials as could be fine
for the very few materials found but one

of the kind of this was off track Laura
and I when we saw the scattering from

this we realized it had some of the right
features this was one that is predicted to

have the right in orbit coupling to
form this strange quantum state and

in the honeycomb networks of one
hundred we call network material and we

did the excitations on that and we got on
the front page in nature materials with it

because people were that interested in it
where you could find any of these things.

OK so.

The biggest challenge was and
this is where in the labs come in

was when you want to do scattering
experiment you need big single crystals.

And we were able to get big single cells
and I won't tell you how because we're

not supposed to tell you how but
because a set.

With growth we could get
the first single crystals

big single crystals of this material and I
think we've still got the only really big

single crystals of this material unless
you've drawn some MARTIN You know.

OK so once you got the big single crystals
we could use our neutron beams in

the following week with a big single
crystal what you can do is we can fire

the neutrons at with beams of just
one energy collect all the scattering

that you get off that from this and
then from the exchange of energy and

momentum to the sample you
can you can reconstruct

all the scattering that's happening
to detach or banks into understanding

the quasi particles that you've excited so
you can work.

All the energy and momentum transfers
that you've made and so you can directly.

You can directly probe these predictions.

Of liquid like dynamics in the material.

And that's what's here.

OK so what we're doing is the looking
at the actual dynamical behavior of all

the spins in the spin network and

comparing it to Kitty of
their behavior and this is

slice fixed energy through six Think
of us like slices through the way from.

Yeah and other bits and this is through
through along the energy axis so

this is like the frequency
dependence of this thing and

you see is relatively featureless kind
of broad things with characteristic.

Waves that are type dependence
which is liquid like.

It's liquid like but
with some modifications into this kind

of star shaped pattern which doesn't
come out of the putative interaction but

you can get when you and some other
realistic couplings into the material.

So the actual X.

eighty cents in behavior in this quantum
spin liquid is really strange it.

Two types of kind of weird particles
quasi particles that one gauge Fluxus.

What qualifies on survives on excitations
Another one was called tender and

Maya run a family and so
they're my rock army ants.

In this and so and those appear in
the spectra in a kind of diffuse way but

these are essentially if you
look here at the spectra.

This Laura part is associated
with the visor on and

this upper part here is related
to the mind around a family owns.

In the scattering So

you see them in it but only by modeling
can you really you know pin this thing.

OK so.

So here we are this is there were several
Katee of materials of been found so

on but all of them are ordering so
none of the repair fit quantum spin

that was because in the the pure quantum
could have quantum spin the current

is a quantum energy gap in it and in fact
this thing doesn't or even when you prove.

It so in these rheumatiz there's enough
other companies in them to make them

only proximate to Katee of behavior
social proximate quantum spin liquids.

So one of the questions is can we
use something like a magnetic field

to stabilize in liquid behavior
by changing the energy balance.

And of.

We nullify some of these other companies
are interfering with the quit.

And so apply my met in fields is
that the number one can do it and

when you apply magnetic fields and
remember when you transfer can readily

work at Miller pitcher or
use high magnetic

fields because we can get them through
really complex sample environments.

No problem doing you know working
down to the lowest temperatures.

And what you find is there is my net
a corridor is indeed suppressed completely

by the magnetic field well below what the
mission field of fuel would actually be so

it seems that applying a magnetic field
does interfere with the ordering of

the material overall and as you increase
the magnetic field in the system.

You.

Lose the order up here and
if you look at high temperatures for

the system has become.

Liquid like this scattering in
field at lowest temperature

is again liquid like suggesting that that
has both quantum fluctuations in it and

that would later behavior same
time without the question about

temperature coming in to causing
the liquid type behavior.

OK So this is kind of nice
This is interesting we've got

we've got a way of stabilizing
the quantum spin that would probably

in this material another
find these other complex.

Let's see if we can get more deeply into
what the physics is of what's going on.

So.

We've got these different objects in it
and the physics I'm going to show is it's

it's really weird physics in
the kitty have been is the thing

has of conservation laws on that
makes it kind of extraordinary.

But the fundamental quantum ords
here at low energies so-called

tries on these are like these are like
loop more little loop more deaths of spin

configurations round these hexagons and
these at like disorder of.

The system so if you thermal.

Stop in populations and actually start
disordering the whole spin that work and

because these are the center
of the despair.

As soon as you prove breach the gap the
quantum energy cap and start properly in

these things in it will cause decoherence
of the overall quantum state very rapidly.

And if this is going to be a short range
ordered system that's become highly

DK here then maybe this
will work classically.

Because where is the quantum in it.

So classical.

So when we.

Riz you can see quantum classical

crossover I don't know how often we
get to see an actual real Express.

But you can see it in magnet.

Right so if you take.

A magnet right a.

Little magnet if it's and you heat or

OP The spin the spin length
will behave as spinning

a mass at low temperatures because it
will see its ordered neighbors there and

that would be like a magnetic field and
that would Zeman splitting between

the energy levels and as long as K.T.
is small compared to that splitting.

Then that will be quantum mechanical way.

K.T. gets big compared to level splitting
this then we know that the density states

of quantum systems when you get
a high density state towards

the classical limit then we'd expect to
become classical So when you hear our.

And there's a condition when
you have to above the Q.

vice temperature divided by the spin
size the system should become classical.

OK so you can actually see this phenomena

because the spin length will
change effectively from S.

to the square of S.S. plus one.

Now this is just basic things but
you don't see this very often so.

This is how you are actually
see it is an experiments

you will see that the energy
scale of the spin X.

been with they teach ins in
the material will go to a value of S.

spin length of which is the quantum spend
their length at low temperatures but

will behave a screw as S.

plus one at higher temperatures for
the crossover being the Q.

of ice temperature divided
by this then roughly.

OK that's weird but I.

Actually if you put temperature
in the right systems and

that's actually most systems
if you use this reasoning

than elevated temperatures you
can use classical mechanics.

To describe it that's
quantum classical crossover

OK now as a caviar actually
some quantum systems

never go classical Newmar home how high
the temperature is you call it so.

I won't go into why that is but

essentially the level space thing is too
big and you never have enough energy.

Going through that the effect of
temperatures able to spread over that can.

Now what we do is first essentially
speculating that the quantum classical top

crossover temperature will be suppressed
and to tear have system first

did magnets in general because because
of frustration because of frustration

you have lots of different configurations
you could have around that spin and so

the levels then will get squeezed up
because of all the different possible

configurations this thing can sense and
that's the argument so

it's not unreasonable to expect that
classical dynamics will work at.

Modest temperatures assuming
reach that quantum gap.

So here's a neat a physics
that you see and.

In can have and so this is Paul secret of
this whole thing I'm going to reveal to

you in this little movie it's so
if you take the.

Set of spins spin that work and
cool it right.

Now what you got to do is to
just gonna flip one of the spins

just make it flip and move so
you can put energy in.

Then this is all you need to
know about Keteyian have.

Physics which is.

If you look at the.

Once when you're pumping the spin
you'll see that this is the spin axis.

Ations and oscillations just move through
this network the network but it isn't

a two dimensional network it's actually
like a one dimensional network of strings.

Right so in fact the ground states are
made up of closed loops Even classically

that daunts can that don't dynamically
connect to their neighbors.

And so all the physics is actually a kind
of one dimensional physics of loops.

As the temperature increases they
cross talk to each other but

in the lowest energy state and
that have temperatures this behaves

like networks one dimensional and that.

And here you can do frequency splitting
into low energy moods and most

which is kind of what violence will come
from and your My around us will come from.

What the spin network to this is classical
calculations and quantum calculations.

For quantum one to Carlow is possible
exactly at the Catie of point for the rest

of the couple is we can't do it but we can
do a really elaborate high temperature.

Computation of how realistic a T.

of systems will work and
it does work classical and

quantum do match each other
when you go above a temperature

about double what the Gap temperature
of the visor on temperature is so

soon as you start putting
a lot of these guys and so

it's right classical dynamics
is it describes a system.

So what's the quantum mechanics in
this kitty of thing where the quantum

exists then surely you're my around us or.

You're one dimensional the the quanta
the attic wanted to happen

at will temperatures in one dimensional
chains and those are spin aunts.

Which or fractionalized spin a half
excitations So a very low temperatures and

quantum spin chains you could
spin fractionalization And so

these are true quantum particles and
true fractionalization happening and

then the low energy moves to zero modes
going through the system that's what

the nice ones are they are a coherent
superposition of all possible

string networks strings through
the network all overlaid on top

of each other quantum mechanically mixed
and that's that's the physics off it so

essentially what happens is you have a
classical ape strongly interacting liquid

and when you cool it down it
quantum condensed into this fully

quantum picture and that happens actually
pretty low temperatures in the system.

So.

What's good about this classical thing
is of course we can then add any

which are field or
whatever arbitrarily and.

We can look at what the effects of
different couplings are in the system so

we know if we're going up to
temperatures we're discipline of all

we can use it to actually find out what
the true Hamiltonian in the system.

So that's actually Luke's because and

surely you have a seven day and
tional temperature.

Three dimensional tensor that.

Your spin configuration your
spin your couplings can be so

that's a huge space to explore.

So we've been used to this thing and that
was the impetus in the in the first place

was ultimately what we are it could
tear for We've been looking for methods

that combines both quantum and classical
calculations to deploy machine learning on

to actually allow us to solve all these
physics problems that we see all.

This beautiful dynamics but
we're having huge problems actually solved

the couplings of materials are and
that's because the face spaces are so huge

we find that even graduate
students can't solve stuff so

it's just impossible see it too hard so
the real purpose is been looking for

ways that we can then use machine learning
by deploying on the massive super its

resources to then find
solutions to the experimental

to describe the experiment of
the measurements that we're seeing.

And so what we're looking at do we
actually have this programmed up for

Titan and I and so we started these
searches through looking at running

you know hundred thousand simulations
in high dimensional space and

using machine learning to
find the optimal solutions.

And then we're that stage one
second stage with hybridized and

with quantum codes overall as well.

So.

There is a fix in this area it's very
challenging there's completely new.

Ideas and it.

Only by having the kind of fidelity of

neutrality to now have we been
able to see any of this stuff.

But it's provided was completely
a new set of challenges and

a new set of opportunities so
I think that this is.

This is a kind of exciting
time in experimental science

computational science where they both
kind of come together in different ways.

We are getting realistic simulations
we are getting a very high quality data

off as well and so

it's probably the big thing that's
impacting on our research field.

Actually to finish off I want to show
you this thing which is part of this.

Which you've probably seen this is this is
the thing with you know this thing you see

this on internet with the gyroscopes
it's actually pretty similar so

this is like a gyroscope.

Insulator Yeah but
it's not a million miles off is.

It what happens when you

take a bus gyroscope these are kind
of flipped floating in a pool.

And you start with no solutions
those oscillations actually

travel round the outside of it.

Like you have a surface states in the top
logical insulator so there are actually

you know not everything is quantum in
particular when you get into top logical.

You have to look at it from the wider
perspective of what's the Hamiltonian

what the equations of motion are.

And so on so I just saved a poll
go back that it was Phil Pincus

put this movie out to me and then at.

The half right so I put.

It.

So overall.

It is a fantastic resource for

your science a lot of the capabilities
that for computing you can apply if.

And you can mess around so
good time to find.

We're National Center for neutron sciences
covers a very wide range of science so

actually this is a scientist marking
using physics and I like it but

it's a chance for work kinds of fields and
you can see what's happening.

In different fields it's a really
exciting time in science overall

it's actually amazing timing in
science and we have plans for

next generation sources which will assure
us leadership well into the future.

And we have really powerful probes for

quantum systems like magnets not some of
my collaborators actually And Janice.

Mara Kuhn.

Works with myself and Christian party.

The simulations for these overall So
thank you very much.

There are.