April 14, 2025 • 34 mins
In this special episode celebrating the United Nations' International Year of Quantum Science and Technology and World Quantum Day, we dive into the mysterious world of quantum entanglement—this time, at the scale of top quarks.
Join us as we speak with Giulia Negro (CMS Experiment, Purdue University) and Yoav Afik (ATLAS Experiment, University of Chicago), two physicists behind groundbreaking results from the Large Hadron Collider's biggest experiments.
From the birth of quantum mechanics 100 years ago to its latest tests in high-energy proton collisions, we explore how the weirdness of the quantum world continues to unfold—one quark pair at a time.
Contributors:
Host: Steven Goldfarb
Editor & Producer: Chetna Krishna
Executive Producer: Jacques Fichet
Ron Suykerbuyk: Technical Lead
Sound Engineering: Piotr Traczyk
Music: The Canettes Blues Band
Join us as we speak with Giulia Negro (CMS Experiment, Purdue University) and Yoav Afik (ATLAS Experiment, University of Chicago), two physicists behind groundbreaking results from the Large Hadron Collider's biggest experiments.
From the birth of quantum mechanics 100 years ago to its latest tests in high-energy proton collisions, we explore how the weirdness of the quantum world continues to unfold—one quark pair at a time.
Contributors:
Host: Steven Goldfarb
Editor & Producer: Chetna Krishna
Executive Producer: Jacques Fichet
Ron Suykerbuyk: Technical Lead
Sound Engineering: Piotr Traczyk
Music: The Canettes Blues Band
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:32):
Hello, everybody,
and welcome to earlymorning coffee at CERN.
I'm Steven Goldfarb and we have a reallyI would say mind boggling show
for you today because we're goingto be talking about quantum mechanics.
And that's a world that boggles I think everybody's mind.
I think as Richard Feynman said, if it doesn't, then you don't get it.
Right.
(00:52):
So, so I have here with me, Giulia Negrofrom the CMS experiment.
Giulia, you work, for Purdue University.
In beautiful Lafayette, Indiana.
By the way,
for my French friends, it doesn't meanthat the university has been lost.
Okay.
It is actually a beautiful place.
Lafayette, Indiana.
(01:13):
And also, with me,to talk about quantum entanglement of top quarks
I have one of my colleagues from theATLAS Experiment, Yoav Afik.
Yoav.
And he is from
as you can see from his cup,the Enrico Fermi Institute,
at the University of Chicagoin Chicago, Illinois.
So actually, your institutesare not far from each other,
(01:34):
but you guys are both farfrom your institutes
We are both based here at CERN, actually.
I beat you on that, though,because I actually work
for the University of Melbournein Australia.
Okay, so this is a very typical thing,here at CERN.
So we're here actuallytoday we're going to be celebrating
the International Day of Quantum Science and Technology
(01:54):
as declared by the United Nations.
UNESCO sponsors these special events.
And we'll be talking
about this really nice measurementthat you guys have made,
about the quantum entanglement of two top quarks
in the Large Hadron Collider,both at ATLAS and at CMS.
(02:18):
And I have to say, first of all, this isa measurement that was not previewed.
We have these these bookswhen we start these experiments.
The yellow books, right?
And I think they were not actually yellowfor the LHC.
But back in the day they were yellow
they would they would sort of listall the different types of physics
and things that we might discover, thingsand measurements, we might make.
And you guys went beyond that. Right.
(02:40):
So we're going to talk about that.
But first I'd like toto get into quantum mechanics if we can.
A little bit.
Maybe you each havean opinion, but usually when UNESCO
does something like this, it'sbecause it's 100 years since something.
So Giulia,
What what do you what would you sayhappened a hundred years ago
That launched this?
(03:00):
Okay.
Well, 100 years ago,there were a lot of, discoveries.
There was, process.
There were a lot of physicists,
that had different ideas.
Yeah.
For example, Heisenbergwith his matrix mechanics,
and Schrödingerwith the wave mechanics.
So that was, what, 1925?
Yes. It's the centennial this year,
(03:24):
that's why it's considered the beginning, but,
yeah, I think it's more of a process
than a specific year of when this all started.That makes a lot of sense.
Yuav, you have an opinion on this?
Yeah. I see it as a process.
I think what Giulia mentioned is where let's saythe formalism
has been designedfor quantum mechanics, but in fact,
(03:46):
I think it started
even earlier when Einsteinintroduced the photoelectric effect.
And so he didn't have the exact formalism
of the quantum mechanics,of course, as we know it today.
But he was able to show that lightcomes in quanta, which is exactly,
you know, what is quantum mechanicsis all about - discrete quantities.
(04:08):
And I think at the time,I mean, he wasn't always a big fan, right?
of quantum mechanics, he thought thatthere was something strange
about not being deterministic.
- I think it was hard for him thatthere are many concepts
that weren't so let's sayintuitive in quantum mechanics.
I mean, as you mentioned before, right?
Feynman said, if you think you understandquantum mechanics means you understood nothing.
(04:29):
Nothing. Yeah.And then we understand nothing.
We're willing to say that as scientists.It's one of the things you find out
when you're a scientist, especiallyat CERN, is how much you don't know
Most of the universewe don't know.
But we've learned a lot, and we're makinga lot of progress, which is important.
So our director, Chetna,
(04:50):
always reminds methat there's a guy named (Satyendra) Bose
who was very importantin all of this as well.
And I think it is interestingbecause some of
the concepts of quantum mechanics
came about somewhat by mistake.
I think, you know, you mentioned,
the photoelectric effect E equals Hv.
(05:11):
And so there were quanta in,the energy,
of a photon, which depends on its frequency.
So you have to use these exact discreet
quanta.
There were also,
even just before that, thatthe equation came from Max Planck, hence
the Planck constant.
When he was trying to understand (black body) radiation.
(05:31):
And he found that using that mathematics,using
this idea of these various frequencies,
you got
solutions to the problemsthat they were looking at.
So the at the time, they were tryingto measure the different discrete spectra
of electrons
orbiting around the proton.
(05:52):
And, and that's kind of cool,I think, because we're experimentalists.
Yeah.
You know, experiment led and
they couldn't come up with a solutionusing classical mechanics.
And so we got to this really, really coolworld of quantum mechanics.
Bose, he also made a mistakewhich was in counting, in the classroom.
(06:13):
And he was talking aboutcounting different states, we have two particles
and they can be one spin up and one spin down.
And you can try to count probabilities.
And normally you say, okay,you can have them both up and both down.
Or there's two different waysit can be up and down.
And if you have something like electrons,where that's the correct way to count
because you can differentiatebetween the two particles.
(06:35):
But Bose those just said, okay, there's two up,
two down, and then there's one with one upand one down.
So three possibilities.
It turned out that worked for bosonslike photons.
And then because they're called bosons right.
Because of Bose.
So it was a really good contribution.
He realised it was a mistake,but then then he started using it.
(06:57):
He said, this works.
And he tried to publish.
And due to various biases
around the world, maybe just the bias ofthis we have never done before
or could have been cultural knows,it wasn't accepted.
But then he sent it to Einstein.
and he said it was good,and it got accepted.
So we always have to fightour biases, both from past,
(07:21):
what we thought was true.
And we have to draft those.
But also there's still cultural biases.
We always get.
Having a placelike CERN is a great place to battle that.
Right?
Because you know,
when you get when you have lunch,you know, who knows who will be sitting next to you.
So, okay, so no one asks the question.
Quantum mechanics.
It's a weird world, right?
(07:42):
It's not like the world that we live in.
The macroscopic.
Giulia, tell me:
What is your favourite effect?
But of course, it's the quantum entanglement.
We are speaking about that today.
And you have
to have to explain thisbecause it's really difficult to comprehend.
(08:02):
And and I supposebecause she said that, you Yoav?
which one?She took entanglement from me,
so I would
say Bell inequality
or the violation of Bell inequality.
And I can explain, shortly, what this all means.
Yeah,you should explain, because Bell is from CERN.
So as we spoke before about Einstein.
(08:24):
So, Einstein, not only Einstein, but
he had a bit of a problemwith entanglement, right?
So let me let me tryand explain the concept of entanglement.
So entanglement tells you ... let's saythat you have two particles.
You cannot describe them
within quantum mechanicsindependently from each other.
(08:46):
What does it mean.
Let's say that we have two particles,two electrons, for example,
in two parts of the universe.These electrons,
they have a property which is calledspin, which we can measure.
So it turns out that if we measure,
if they are coming
from the same sourcewhich we call as singlet,
and we measure the spinof one of the electrons
(09:07):
on one side of the universe,we would immediately know the outcome
on the other one.
Immediately? So not with time for it to go around the WWW?
And this is mind blowing, right.
And it can tell you, for example,it implies that the information
travels faster than the speed of light,which contradicts,
Einstein's theory of relativity.
So this is why, in the 30's, Einstein
(09:29):
together with, with Podolsky and Rosencame up with the
famous paper of the EPR paradox,the Einstein, Podolsky and Rosen paradox,
which basically claims that quantummechanics is an incomplete theory.
We have a set of hidden variableswithin the theory, which tells us
before the measurement itself, the outcomeof the measurement of one electron and the other one.
(09:52):
And we need more variables
in order to describe this theory.
Okay.
Now, in the 60's came John Stewart Bell,
and showed that if these theories exist,
it means that they have to fulfil
this, very famous Bell inequality.
So you can actually exclude these theories
with additional local hidden variables
(10:15):
as claimed by Einstein, Podolsky and Rosen.
by breaking the Bell inequality.
So it so it's broken then.
It has been measured to be violated
many times already. Yes.
And there was,
there was a Nobel Prize recentlyfor that a couple of years ago, yes.
(10:38):
If I remember somewherearound here, 2022,
the winners of the 2022 Nobel Prizewere Aspect, Clauser and Zeilinger
Exactly, Aspect, Clauser and Zeilinger.
Very good.
Yes, exactly. For testing this concept.
And that's important,I think, Bell was at CERN actually.
Yes he was.
So we have we have some smart people here,
(10:59):
On occasion, there are some smart people here.
So as long as we're talking about
quantum entanglement here,
you guys both independentlydid measurements of quantum entanglement.
Of course.
That's why we have different experiments, right?
You know, andCMS and Atlas are beautiful experiments.
They both enormous.
(11:20):
They both have a lot of people, like 5000 or 6000 people on CMS, right?
5000 or 6000 on ATLAS.
There's 3000 authors, I think
Yeah, almost
You know thatthat means that I've written less.
I've been on ATLAS with you.
Even before you,
Yeah, because I think, I've been around since 1998
(11:42):
and I still haven't writtena total of one paper.
Right.
Because if you take and divide by 3000,we have to write more papers, I think.
So you've independently done this,I think, the story,
of how you came up with the ideaof looking
for quantum entanglement,
(12:04):
in the LHC, because just like I said,this is never too far before.
I think you have the story.- We came up with the idea.
So together with, Juan Ramón Muñoz de Nova
when I was in my Ph.D.,we were in the same institute.
He's actually coming from the fieldof condensed matter physics.
So this already tells us something about the interdisciplinary nature of this idea.
(12:28):
And we were friends.
And we met for coffee breaks at the TECHNIONwhere I did my PhD.
And we chatted.
Also, sometimes about physics, of course.
Yeah, yeah.
Well, more than sometimes. Yeah.
And then he asked me
if I think that we can measureentanglement at the LHC.
I said, okay,that's a very interesting question.
(12:52):
And I started to,
to do some
research and to see the possibilities.
Then I saw this,
very unique particle,
which is the top quark,which I assume we will discuss about soon.
Yeah.
And this seemed to mealso by the previous measurements
that I saw were doneusing top quarks as the perfect system.
(13:15):
to try and measure quantum entanglement at the LHC
And that is what we did.
Someone had thought about that idea
that you could use the top quark.
So we thought about it together,you know, Juan and myself together.
And this led to a paper publishedabout a year after we chatted about it.
This was basically the baseline
(13:36):
for both of the measurements.
And you were a student at the time?- Yes, I was a PhD student back then.
That's actually our workforce.
People don't realise that.
But like more than a third of the authorson our experiments are PhD students.
and they're also the people you'll find onshifts a lot.
Postdocs are also okay,The rest of us
(13:59):
are kind of useless.
but we have fun anyhow!
So you asked about it.
Maybe Giulia can explain a little bit more
Why is the top quark
something that we can look at
in this case.
So the top quark is very specialbecause,
a differencewith respect to the other quarks is that
(14:20):
it decays before it can hadronise.
So the information, for example,the spin information, of the
the top quark is transferred,to its decay products.
Interesting that you bring up hadronise,so quarks are very special.
Yes, they are fundamental particles
They're fundamental,
when we talk about
(14:40):
doing particle physics at CERN,
So we talked about lookingat the elementary
or fundamental particles those thingsyou can't cut a top quark in half.
Right.
So we have 6 of these quarks.
Two of them are stablebecause they're really light.
The up and the down.The other ones, they appear for short times.
And then I guess the the more massivethey are,
(15:02):
the quicker they decay.Indeed,
the top quark is the one with the highest mass
it is 40 times, larger than the bottom quark.
It's about 180 times the mass of the proton.
And a proton is made up
of quarks.
Right. So yeah.
The top quark is super massive.
(15:25):
It's the most massive of any of the,any of the elementary particles.
Even the bosons, like
the W and the Z, even the Higgseven more massive than the Higgs.
So it doesn't have a chance
like the other quarkshave this wonderful life because
as soon as they're born, they finda partner or a couple partners, right.
And they hang out with them,
(15:46):
and it takes a huge amount of effortto pull them apart.
It's the strong nuclear force.
And when you do when you finally get these two
quark and antiquark and you pull them apart, suddenly out of, out of nowhere
out of the vacuum,a couple other quarks appear.
they can't get to, they get divorced andthey immediately got new partners.
(16:09):
But the poor top quark is all alone.
and it disintegrates, it transforms
to other
I don't like using decays,
I agree, my wife tells me that more massive you get
the quicker you'll decay,
And I agree that like,
you know, I don't like this wordbecause when you think of decays,
you think of the breaking into parts
and the top quark doesn't break into parts,it transforms into energy.
(16:32):
Plus the
W and the bottom quark
Exactly.
So you have these decayproducts, you know,
and then you can look at
their energy, their momentum, their angles
and then you can
figure things out from that?
In our case for the entanglement,
(16:54):
we measured that the angular correlationbetween these decay products,
So in this case with the leptons,that decay from the top quark.
Okay.
So you have you have a couple leptons.
It's complicated when they decay right?
Top quarks have a few possibilities to decay,we look specifically at,
we need to say that the top quarks are createdin a pair of the top quark and its antimatter counterpart, the antitop
(17:21):
And between these two,we actually measured the entanglement
the spin entanglementbetween the top of the antitop.
Both of them can decay,
so they can
have a few possibilitiesto decay.
One of the possibilities to decayto final states with charged leptons.
So, for example, electron or positron
(17:42):
or the heavier twin of the electron
not exactly the twin,
the muon or the antimuon
why we do this?
Because the in our detectors,we measure
the charged leptons invery good precision.
(18:02):
And we need to have the tracksbeing measured very precisely.
Because, as Giulia said before,
in the end, we need to measurethe angular separations between one charged lepton from one top,
to the other charged leptonfrom the antitop.
And this way we can deduce somethingabout their spin correlations
and about the entanglementbetween the top and anti top.
So it tells youthat they are correlated. Yes.
(18:25):
That's interesting.
And you came up with this over coffee,
during a conference in, more or less.
Yeah, a regular coffee break in the office.
Oh, yeah. Okay.
Coffee is very important, by the way.
(18:47):
So Chetna wants to know.
What exactly does it mean?
So under certain circumstances,
they're entangledyou measure that they are entangled
So how are they entangled,what is the meaning behind this?
So, as Yoav said before, that
means that you cannot describe,the spin state of one quark independently from the other
(19:12):
in quantum mechanics,
we use, just for example,the wave function
to describe the state of a given particleor a given system.
we can also use what,what is called the density matrix,
which gives us the densityto be in some specific states.
And the idea behind entanglementis that if
(19:34):
we have this density matrix which describesthe quantum state of the system,
and we have defined this for the top and the antitop.
for the system of the two,
we cannot describe thisjust by a combination
of the individual spin densitymatrix of each one of the top
or the antitop.
This tells usthat the state is not separable.
(19:55):
We cannot describe the state of the top and antitopindependently from the other.
You know, if you're listening
and you don't completely get thisit's normal, right?
This is a world that we don't live in.
It's like the electronsthat were mentioned before, right?
Because we know the outcomeof the measurement of
(20:18):
one electron
after we did the measurementon the other one, it tells us
that basically we cannot describethe quantum state
of both of the electrons, sorry,as an independent combination
of the states of both of them,
just because the correlations look sostrong, there's so much affect each other.
(20:39):
And so you have to describethe system as a whole.
So I understand this
was not simple to do, there weresome hallenges in doing the analysis.
Where to start?
Well, one challenge is that we had to deal
with the modelling of the t-tbar
(21:00):
production threshold region
So, close to
two times the mass of the top quark
And
this region is not very well modelled yet,
So we had to come up with a
simplified model, and then we introduced this
pseudoscalar resonance,that is a bound state of a top quark and a top antiquark,
(21:25):
So this is called toponium.
and then this improves
our modelling of this region.
Including this was not an easy process
and, in our measurements
we managed to do it.
So in ATLAS they came out firstbut they didn't include this in the model.
Yeah,we were able to show that our measurement
(21:51):
is not affected by this effect.
But nevertheless,this is actually a super interesting point
because this is a very cool effect.
The idea behind this is that
close to the production thresholdwhere the top and anti-top are slow,
there are some non-relativistic effects that enters
(22:11):
this is the so-called toponium.
It's funny,this is not included by default
in our Monte Carlo simulations.
It's a non-perturbative effect.
Actually, the tools we used and that were used in CMS,
let's say give a better and better
(22:33):
grasp of this specific effect
and perhaps also the possibility to measure it
and to develop some observableswhich are more sensitive to this state
because this state brings an enhancement
of the more entangled eventsto a cross section.
So it basically meansthat we should see more entangled events than
(22:54):
than expectedfrom Monte Carlo simulations that we use.
So you mentioned a few things in there.
I'm not sure ifwe're going to go into details, but now,
QCD is very complicated.
So you you have these different realms,right?
the perturbative and the non perturbative,which has to do
(23:16):
with relativity effects? Yes.
The nice thing is that actually these measurementof entanglement, beyond being
these measurements of entanglement, beyond
being just, you know, being a very nice
(23:36):
and cool interdisciplinary thing to measure,they actually brought a lot of benefits
to high-energy physics, to measure processes of high-energy physics.
So, so tell me a little bit more about this.What are the benefits that come from this.
So besides the
possibility to have a better grasp of toponym,
mentioned before by Giulia,
So for example,if you look at the measurement by CMS,
(23:57):
you can see that the data agrees betterwith the existence of this toponium.
Which is quite nice, because if we look at our
resolution in the detectorto reconstruct the invariant mass
of the top and the anti top,
We can never see this because it's
a lot more narrow than our t-tbar resolution.
(24:18):
But with the spin correlation effects andentanglement observables,
it's possible to see some signs of this,
It also gave a push to theorists,to investigate a bit more.
And this also came up in a fewother measurements
by CMS, these effects,
(24:40):
In addition, I have to say that
there are many new techniques to search for physics
beyond the Standard Model that has been developedbased on the quantum observables
that we thought about andthat we looked at in our measurements.
Physics beyond the Standard Model
is something we all want becausethis is what makes our careers here
(25:04):
as experimentalists is forever
trying to find outwhat's wrong with theory.
We love theorists. We love theorists.
But they only explain5% of the universe.
Or less, we don't even know gravity.
Okay, so there are a lot of things,a lot of big questions out there.
And so we're always looking to seewhere the model can break.
(25:26):
And that gives us hints.
And so to see thisit gives us some more tools.
I should mentiontoponium is only one of the oniums right?
There are others that have been measured
bottomonium, charmonium,
meaning that you have a charm quark and an anti charm,
bottom, or anti bottom,but these we can measure more directly.
(25:51):
Yes, but
with the top it's not so easy.
Also,
it's not exactly the same thingbecause the tops really decay before
they can form like a particlea bound state, a meson,
So maybe toponium is a bitof a misleading name.
So they haven't really formed,
They exchange a few gluonsbefore they decay.
(26:13):
Gluons being the carriersof the strong nuclear force,
like photons,we have photons coming through us right now.
That's what's inside these protons.
The gluons, great name.
Keeps it all glued.
So my next question for you is,what's next?
I mean, if you you guys learn offfrom each other, this is very common
(26:36):
for experiments. We go to conferencesor we have discussions or seminars.
That's when we share information.
Of course, you know,
some information gets shared during coffee breaks,
As we've learned,
But now, I mean,
will ATLAS, for example,do a measurement with toponium
(26:59):
included, or,
you found that it's an effect that doesn'twe don't know.
Can't say.
Oh, yeah.
We can't always say these things.
In general, how do you see us going forward withthese measurements?
(27:19):
Well there is not only quantum entanglementthat we can measure,
there are also lots of other quantum correlations,
like Bell's inequality, as we mentioned before.
So for sure, one of the next
point will be to also discover
these new quantum effects.
I want to give maybe a number.
(27:40):
Just to give you an idea.
Why is it interesting to do these measurements
So we mentioned before the Nobel Prizein physics.
Right.
And it was done by testing
the entanglement and the Bell inequality with photons.
What we do here at the LHC,the measurement
that both CMS and ATLAS did
with top quarks, is about12 orders of magnitude higher in energy than
(28:03):
all of these extremely importantlaboratory experiments.
So when you go so muchhigher in the scale,
there is alreadya fundamental interest of why we do this.
And what CMS and ATLAS did,
at least to me, is a proof of concept
that we can actually performsuch measurements using collider physics,
(28:25):
using collider experiments,
and there is so much room for doing more.So many other proposals,
to measure many other things.
A lot has come up
since then.
And we think we can sayboth in CMS and ATLAS we are
now working on performing these other measurementsin some other parts of phase space with top quarks,
(28:45):
or, for example, with the Higgs boson decay.
And so there is a lot to do.
This is the first time this is being donein collider research.
It was the measurement with the highestenergy ever performed.
At the LHC it was the first time.
It was done before
(29:06):
in colliders with mesons
at lower energies, in particular with B mesons,
but it's a different type of entanglement.
It's more flavour entanglementit's related to other properties of particles.
But never at the LHC,
(29:28):
never with quarks
which are fundamental particles,
It's pure quantum entanglementbecause it's a fundamental particle
Remember the example that I gave with
both of the electrons at other parts of the Universe.
Yeah. This was never done actually.
Yeah.
That would take some effort to go to different parts of the universe.
(29:50):
Well yes.
But in general between two whatwe call free electrons.
Yeah.
I mean it was done with a bitmore complicated systems.
Here, we actually measured the entanglementbetween two quarks which are
let's say quasi-free particles.
So, you have theorists
(30:11):
coming to you, saying,I got some ideas now, right?
I guess you have both been approached by theorists
and different things in quantum mechanics thatcan be measured.
Also though, what we have coming up in a few years,
we're going to tear our experiments apart
and we're going to goto a High-Luminosity LHC.
(30:31):
So actually, we have,a year and a half or so
of runningand then nothing for 3 and a half to 4 years.
And then we start up with brand newbeautiful detectors
made to be able to go at a much higher rate,so we'll have much higher statistics,
will that help?
Will that be of use to you?
We will have more data so we can get measurements more precisely.
(30:53):
So, for example,I mean, as was mentioned before by Giulia,
we have a lot more concepts ofquantum correlations that we can measure.
If you look, for example at Bell state,or Bell inequality,
if we look at the measurement,
in t-tbar,we have to go to a lot more extreme
parts of phase space,to perform these measurements.
(31:16):
And if we have more datain order to do it,
it means that we have more eventsand more statistics to actually be able to
do these measurements because,
of course,we need statistics to make
precise measurementsSo extreme parts of phase space.
Sounds like a great place to go.
(31:36):
But it is
sort of those things which are rare.
It's rare to find something that has this momentum,
this energy,
this mass, whatever.
Those are what we consider phase space.
And yeah, with more statistics.
Even if we're not going to increase energy,because the LHC won't increase
much more,
we are about as high as we can go,
(31:58):
having much more datais a way of also going up in energy
because we can produce those thingsthe more rare things you will see there.
Okay.
Well,I'm looking forward to seeing new results.
I think it's going to be a lot of fun.I think especially because
you've gone into an areathat we haven't been in before.
So congratulations on doing that.
(32:20):
So thank you.
I want you to thank Giulia Negro
From Purdue University,in the CMS experiment.
And also Yoav Afik from the ATLAS experimentand from
Enrico Fermi Institute,as shown on his cup
and you have your beautiful CMS cup here.
And I celebrate outreach.
(32:41):
with my IPPOG cup here.
This has been early morning coffeeat CERN.
It's a podcast by the scientists of CERN
about the science of CERN.
You can find all of our episodeson CERN's YouTube channel.
And if you don't want to look at ourlovely faces, you can also listen to us
anywhere where you get a podcastEarly Morning Coffee at CERN.
(33:04):
Anywhere.
Our editor and producer is Chetna Krishna.
Our executive producer is Jacques FichetStudio.
Ron Suykerbuyk is our technical lead.
Our studio manager is Max Brice,sound engineer by Piotr Traczyk.
Our original theme comes from the Canettes Blues Band
with piano by Wojt "Play it in any key" Krajewski.
(33:25):
Many thanks to Paola Catapano, Matthew Chalmersand Arnaud Marsollier
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Rather, the Education, Communication and Outreachteam at CERN for providing us with access
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(33:47):
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My name is Steven Goldfarb, and thishas been Early Morning Coffee at CERN.
We'll see you again next month.
Hello, everybody,
and welcome to earlymorning coffee at CERN.
I'm Steven Goldfarb and we have a reallyI would say mind boggling show
for you today because we're goingto be talking about quantum mechanics.
And that's a world that boggles I think everybody's mind.
I think as Richard Feynman said, if it doesn't, then you don't get it.
Right.
(00:52):
So, so I have here with me, Giulia Negrofrom the CMS experiment.
Giulia, you work, for Purdue University.
In beautiful Lafayette, Indiana.
By the way,
for my French friends, it doesn't meanthat the university has been lost.
Okay.
It is actually a beautiful place.
Lafayette, Indiana.
(01:13):
And also, with me,to talk about quantum entanglement of top quarks
I have one of my colleagues from theATLAS Experiment, Yoav Afik.
Yoav.
And he is from
as you can see from his cup,the Enrico Fermi Institute,
at the University of Chicagoin Chicago, Illinois.
So actually, your institutesare not far from each other,
(01:34):
but you guys are both farfrom your institutes
We are both based here at CERN, actually.
I beat you on that, though,because I actually work
for the University of Melbournein Australia.
Okay, so this is a very typical thing,here at CERN.
So we're here actuallytoday we're going to be celebrating
the International Day of Quantum Science and Technology
(01:54):
as declared by the United Nations.
UNESCO sponsors these special events.
And we'll be talking
about this really nice measurementthat you guys have made,
about the quantum entanglement of two top quarks
in the Large Hadron Collider,both at ATLAS and at CMS.
(02:18):
And I have to say, first of all, this isa measurement that was not previewed.
We have these these bookswhen we start these experiments.
The yellow books, right?
And I think they were not actually yellowfor the LHC.
But back in the day they were yellow
they would they would sort of listall the different types of physics
and things that we might discover, thingsand measurements, we might make.
And you guys went beyond that. Right.
(02:40):
So we're going to talk about that.
But first I'd like toto get into quantum mechanics if we can.
A little bit.
Maybe you each havean opinion, but usually when UNESCO
does something like this, it'sbecause it's 100 years since something.
So Giulia,
What what do you what would you sayhappened a hundred years ago
That launched this?
(03:00):
Okay.
Well, 100 years ago,there were a lot of, discoveries.
There was, process.
There were a lot of physicists,
that had different ideas.
Yeah.
For example, Heisenbergwith his matrix mechanics,
and Schrödingerwith the wave mechanics.
So that was, what, 1925?
Yes. It's the centennial this year,
(03:24):
that's why it's considered the beginning, but,
yeah, I think it's more of a process
than a specific year of when this all started.That makes a lot of sense.
Yuav, you have an opinion on this?
Yeah. I see it as a process.
I think what Giulia mentioned is where let's saythe formalism
has been designedfor quantum mechanics, but in fact,
(03:46):
I think it started
even earlier when Einsteinintroduced the photoelectric effect.
And so he didn't have the exact formalism
of the quantum mechanics,of course, as we know it today.
But he was able to show that lightcomes in quanta, which is exactly,
you know, what is quantum mechanicsis all about - discrete quantities.
(04:08):
And I think at the time,I mean, he wasn't always a big fan, right?
of quantum mechanics, he thought thatthere was something strange
about not being deterministic.
- I think it was hard for him thatthere are many concepts
that weren't so let's sayintuitive in quantum mechanics.
I mean, as you mentioned before, right?
Feynman said, if you think you understandquantum mechanics means you understood nothing.
(04:29):
Nothing. Yeah.And then we understand nothing.
We're willing to say that as scientists.It's one of the things you find out
when you're a scientist, especiallyat CERN, is how much you don't know
Most of the universewe don't know.
But we've learned a lot, and we're makinga lot of progress, which is important.
So our director, Chetna,
(04:50):
always reminds methat there's a guy named (Satyendra) Bose
who was very importantin all of this as well.
And I think it is interestingbecause some of
the concepts of quantum mechanics
came about somewhat by mistake.
I think, you know, you mentioned,
the photoelectric effect E equals Hv.
(05:11):
And so there were quanta in,the energy,
of a photon, which depends on its frequency.
So you have to use these exact discreet
quanta.
There were also,
even just before that, thatthe equation came from Max Planck, hence
the Planck constant.
When he was trying to understand (black body) radiation.
(05:31):
And he found that using that mathematics,using
this idea of these various frequencies,
you got
solutions to the problemsthat they were looking at.
So the at the time, they were tryingto measure the different discrete spectra
of electrons
orbiting around the proton.
(05:52):
And, and that's kind of cool,I think, because we're experimentalists.
Yeah.
You know, experiment led and
they couldn't come up with a solutionusing classical mechanics.
And so we got to this really, really coolworld of quantum mechanics.
Bose, he also made a mistakewhich was in counting, in the classroom.
(06:13):
And he was talking aboutcounting different states, we have two particles
and they can be one spin up and one spin down.
And you can try to count probabilities.
And normally you say, okay,you can have them both up and both down.
Or there's two different waysit can be up and down.
And if you have something like electrons,where that's the correct way to count
because you can differentiatebetween the two particles.
(06:35):
But Bose those just said, okay, there's two up,
two down, and then there's one with one upand one down.
So three possibilities.
It turned out that worked for bosonslike photons.
And then because they're called bosons right.
Because of Bose.
So it was a really good contribution.
He realised it was a mistake,but then then he started using it.
(06:57):
He said, this works.
And he tried to publish.
And due to various biases
around the world, maybe just the bias ofthis we have never done before
or could have been cultural knows,it wasn't accepted.
But then he sent it to Einstein.
and he said it was good,and it got accepted.
So we always have to fightour biases, both from past,
(07:21):
what we thought was true.
And we have to draft those.
But also there's still cultural biases.
We always get.
Having a placelike CERN is a great place to battle that.
Right?
Because you know,
when you get when you have lunch,you know, who knows who will be sitting next to you.
So, okay, so no one asks the question.
Quantum mechanics.
It's a weird world, right?
(07:42):
It's not like the world that we live in.
The macroscopic.
Giulia, tell me:
What is your favourite effect?
But of course, it's the quantum entanglement.
We are speaking about that today.
And you have
to have to explain thisbecause it's really difficult to comprehend.
(08:02):
And and I supposebecause she said that, you Yoav?
which one?She took entanglement from me,
so I would
say Bell inequality
or the violation of Bell inequality.
And I can explain, shortly, what this all means.
Yeah,you should explain, because Bell is from CERN.
So as we spoke before about Einstein.
(08:24):
So, Einstein, not only Einstein, but
he had a bit of a problemwith entanglement, right?
So let me let me tryand explain the concept of entanglement.
So entanglement tells you ... let's saythat you have two particles.
You cannot describe them
within quantum mechanicsindependently from each other.
(08:46):
What does it mean.
Let's say that we have two particles,two electrons, for example,
in two parts of the universe.These electrons,
they have a property which is calledspin, which we can measure.
So it turns out that if we measure,
if they are coming
from the same sourcewhich we call as singlet,
and we measure the spinof one of the electrons
(09:07):
on one side of the universe,we would immediately know the outcome
on the other one.
Immediately? So not with time for it to go around the WWW?
And this is mind blowing, right.
And it can tell you, for example,it implies that the information
travels faster than the speed of light,which contradicts,
Einstein's theory of relativity.
So this is why, in the 30's, Einstein
(09:29):
together with, with Podolsky and Rosencame up with the
famous paper of the EPR paradox,the Einstein, Podolsky and Rosen paradox,
which basically claims that quantummechanics is an incomplete theory.
We have a set of hidden variableswithin the theory, which tells us
before the measurement itself, the outcomeof the measurement of one electron and the other one.
(09:52):
And we need more variables
in order to describe this theory.
Okay.
Now, in the 60's came John Stewart Bell,
and showed that if these theories exist,
it means that they have to fulfil
this, very famous Bell inequality.
So you can actually exclude these theories
with additional local hidden variables
(10:15):
as claimed by Einstein, Podolsky and Rosen.
by breaking the Bell inequality.
So it so it's broken then.
It has been measured to be violated
many times already. Yes.
And there was,
there was a Nobel Prize recentlyfor that a couple of years ago, yes.
(10:38):
If I remember somewherearound here, 2022,
the winners of the 2022 Nobel Prizewere Aspect, Clauser and Zeilinger
Exactly, Aspect, Clauser and Zeilinger.
Very good.
Yes, exactly. For testing this concept.
And that's important,I think, Bell was at CERN actually.
Yes he was.
So we have we have some smart people here,
(10:59):
On occasion, there are some smart people here.
So as long as we're talking about
quantum entanglement here,
you guys both independentlydid measurements of quantum entanglement.
Of course.
That's why we have different experiments, right?
You know, andCMS and Atlas are beautiful experiments.
They both enormous.
(11:20):
They both have a lot of people, like 5000 or 6000 people on CMS, right?
5000 or 6000 on ATLAS.
There's 3000 authors, I think
Yeah, almost
You know thatthat means that I've written less.
I've been on ATLAS with you.
Even before you,
Yeah, because I think, I've been around since 1998
(11:42):
and I still haven't writtena total of one paper.
Right.
Because if you take and divide by 3000,we have to write more papers, I think.
So you've independently done this,I think, the story,
of how you came up with the ideaof looking
for quantum entanglement,
(12:04):
in the LHC, because just like I said,this is never too far before.
I think you have the story.- We came up with the idea.
So together with, Juan Ramón Muñoz de Nova
when I was in my Ph.D.,we were in the same institute.
He's actually coming from the fieldof condensed matter physics.
So this already tells us something about the interdisciplinary nature of this idea.
(12:28):
And we were friends.
And we met for coffee breaks at the TECHNIONwhere I did my PhD.
And we chatted.
Also, sometimes about physics, of course.
Yeah, yeah.
Well, more than sometimes. Yeah.
And then he asked me
if I think that we can measureentanglement at the LHC.
I said, okay,that's a very interesting question.
(12:52):
And I started to,
to do some
research and to see the possibilities.
Then I saw this,
very unique particle,
which is the top quark,which I assume we will discuss about soon.
Yeah.
And this seemed to mealso by the previous measurements
that I saw were doneusing top quarks as the perfect system.
(13:15):
to try and measure quantum entanglement at the LHC
And that is what we did.
Someone had thought about that idea
that you could use the top quark.
So we thought about it together,you know, Juan and myself together.
And this led to a paper publishedabout a year after we chatted about it.
This was basically the baseline
(13:36):
for both of the measurements.
And you were a student at the time?- Yes, I was a PhD student back then.
That's actually our workforce.
People don't realise that.
But like more than a third of the authorson our experiments are PhD students.
and they're also the people you'll find onshifts a lot.
Postdocs are also okay,The rest of us
(13:59):
are kind of useless.
but we have fun anyhow!
So you asked about it.
Maybe Giulia can explain a little bit more
Why is the top quark
something that we can look at
in this case.
So the top quark is very specialbecause,
a differencewith respect to the other quarks is that
(14:20):
it decays before it can hadronise.
So the information, for example,the spin information, of the
the top quark is transferred,to its decay products.
Interesting that you bring up hadronise,so quarks are very special.
Yes, they are fundamental particles
They're fundamental,
when we talk about
(14:40):
doing particle physics at CERN,
So we talked about lookingat the elementary
or fundamental particles those thingsyou can't cut a top quark in half.
Right.
So we have 6 of these quarks.
Two of them are stablebecause they're really light.
The up and the down.The other ones, they appear for short times.
And then I guess the the more massivethey are,
(15:02):
the quicker they decay.Indeed,
the top quark is the one with the highest mass
it is 40 times, larger than the bottom quark.
It's about 180 times the mass of the proton.
And a proton is made up
of quarks.
Right. So yeah.
The top quark is super massive.
(15:25):
It's the most massive of any of the,any of the elementary particles.
Even the bosons, like
the W and the Z, even the Higgseven more massive than the Higgs.
So it doesn't have a chance
like the other quarkshave this wonderful life because
as soon as they're born, they finda partner or a couple partners, right.
And they hang out with them,
(15:46):
and it takes a huge amount of effortto pull them apart.
It's the strong nuclear force.
And when you do when you finally get these two
quark and antiquark and you pull them apart, suddenly out of, out of nowhere
out of the vacuum,a couple other quarks appear.
they can't get to, they get divorced andthey immediately got new partners.
(16:09):
But the poor top quark is all alone.
and it disintegrates, it transforms
to other
I don't like using decays,
I agree, my wife tells me that more massive you get
the quicker you'll decay,
And I agree that like,
you know, I don't like this wordbecause when you think of decays,
you think of the breaking into parts
and the top quark doesn't break into parts,it transforms into energy.
(16:32):
Plus the
W and the bottom quark
Exactly.
So you have these decayproducts, you know,
and then you can look at
their energy, their momentum, their angles
and then you can
figure things out from that?
In our case for the entanglement,
(16:54):
we measured that the angular correlationbetween these decay products,
So in this case with the leptons,that decay from the top quark.
Okay.
So you have you have a couple leptons.
It's complicated when they decay right?
Top quarks have a few possibilities to decay,we look specifically at,
we need to say that the top quarks are createdin a pair of the top quark and its antimatter counterpart, the antitop
(17:21):
And between these two,we actually measured the entanglement
the spin entanglementbetween the top of the antitop.
Both of them can decay,
so they can
have a few possibilitiesto decay.
One of the possibilities to decayto final states with charged leptons.
So, for example, electron or positron
(17:42):
or the heavier twin of the electron
not exactly the twin,
the muon or the antimuon
why we do this?
Because the in our detectors,we measure
the charged leptons invery good precision.
(18:02):
And we need to have the tracksbeing measured very precisely.
Because, as Giulia said before,
in the end, we need to measurethe angular separations between one charged lepton from one top,
to the other charged leptonfrom the antitop.
And this way we can deduce somethingabout their spin correlations
and about the entanglementbetween the top and anti top.
So it tells youthat they are correlated. Yes.
(18:25):
That's interesting.
And you came up with this over coffee,
during a conference in, more or less.
Yeah, a regular coffee break in the office.
Oh, yeah. Okay.
Coffee is very important, by the way.
(18:47):
So Chetna wants to know.
What exactly does it mean?
So under certain circumstances,
they're entangledyou measure that they are entangled
So how are they entangled,what is the meaning behind this?
So, as Yoav said before, that
means that you cannot describe,the spin state of one quark independently from the other
(19:12):
in quantum mechanics,
we use, just for example,the wave function
to describe the state of a given particleor a given system.
we can also use what,what is called the density matrix,
which gives us the densityto be in some specific states.
And the idea behind entanglementis that if
(19:34):
we have this density matrix which describesthe quantum state of the system,
and we have defined this for the top and the antitop.
for the system of the two,
we cannot describe thisjust by a combination
of the individual spin densitymatrix of each one of the top
or the antitop.
This tells usthat the state is not separable.
(19:55):
We cannot describe the state of the top and antitopindependently from the other.
You know, if you're listening
and you don't completely get thisit's normal, right?
This is a world that we don't live in.
It's like the electronsthat were mentioned before, right?
Because we know the outcomeof the measurement of
(20:18):
one electron
after we did the measurementon the other one, it tells us
that basically we cannot describethe quantum state
of both of the electrons, sorry,as an independent combination
of the states of both of them,
just because the correlations look sostrong, there's so much affect each other.
(20:39):
And so you have to describethe system as a whole.
So I understand this
was not simple to do, there weresome hallenges in doing the analysis.
Where to start?
Well, one challenge is that we had to deal
with the modelling of the t-tbar
(21:00):
production threshold region
So, close to
two times the mass of the top quark
And
this region is not very well modelled yet,
So we had to come up with a
simplified model, and then we introduced this
pseudoscalar resonance,that is a bound state of a top quark and a top antiquark,
(21:25):
So this is called toponium.
and then this improves
our modelling of this region.
Including this was not an easy process
and, in our measurements
we managed to do it.
So in ATLAS they came out firstbut they didn't include this in the model.
Yeah,we were able to show that our measurement
(21:51):
is not affected by this effect.
But nevertheless,this is actually a super interesting point
because this is a very cool effect.
The idea behind this is that
close to the production thresholdwhere the top and anti-top are slow,
there are some non-relativistic effects that enters
(22:11):
this is the so-called toponium.
It's funny,this is not included by default
in our Monte Carlo simulations.
It's a non-perturbative effect.
Actually, the tools we used and that were used in CMS,
let's say give a better and better
(22:33):
grasp of this specific effect
and perhaps also the possibility to measure it
and to develop some observableswhich are more sensitive to this state
because this state brings an enhancement
of the more entangled eventsto a cross section.
So it basically meansthat we should see more entangled events than
(22:54):
than expectedfrom Monte Carlo simulations that we use.
So you mentioned a few things in there.
I'm not sure ifwe're going to go into details, but now,
QCD is very complicated.
So you you have these different realms,right?
the perturbative and the non perturbative,which has to do
(23:16):
with relativity effects? Yes.
The nice thing is that actually these measurementof entanglement, beyond being
these measurements of entanglement, beyond
being just, you know, being a very nice
(23:36):
and cool interdisciplinary thing to measure,they actually brought a lot of benefits
to high-energy physics, to measure processes of high-energy physics.
So, so tell me a little bit more about this.What are the benefits that come from this.
So besides the
possibility to have a better grasp of toponym,
mentioned before by Giulia,
So for example,if you look at the measurement by CMS,
(23:57):
you can see that the data agrees betterwith the existence of this toponium.
Which is quite nice, because if we look at our
resolution in the detectorto reconstruct the invariant mass
of the top and the anti top,
We can never see this because it's
a lot more narrow than our t-tbar resolution.
(24:18):
But with the spin correlation effects andentanglement observables,
it's possible to see some signs of this,
It also gave a push to theorists,to investigate a bit more.
And this also came up in a fewother measurements
by CMS, these effects,
(24:40):
In addition, I have to say that
there are many new techniques to search for physics
beyond the Standard Model that has been developedbased on the quantum observables
that we thought about andthat we looked at in our measurements.
Physics beyond the Standard Model
is something we all want becausethis is what makes our careers here
(25:04):
as experimentalists is forever
trying to find outwhat's wrong with theory.
We love theorists. We love theorists.
But they only explain5% of the universe.
Or less, we don't even know gravity.
Okay, so there are a lot of things,a lot of big questions out there.
And so we're always looking to seewhere the model can break.
(25:26):
And that gives us hints.
And so to see thisit gives us some more tools.
I should mentiontoponium is only one of the oniums right?
There are others that have been measured
bottomonium, charmonium,
meaning that you have a charm quark and an anti charm,
bottom, or anti bottom,but these we can measure more directly.
(25:51):
Yes, but
with the top it's not so easy.
Also,
it's not exactly the same thingbecause the tops really decay before
they can form like a particlea bound state, a meson,
So maybe toponium is a bitof a misleading name.
So they haven't really formed,
They exchange a few gluonsbefore they decay.
(26:13):
Gluons being the carriersof the strong nuclear force,
like photons,we have photons coming through us right now.
That's what's inside these protons.
The gluons, great name.
Keeps it all glued.
So my next question for you is,what's next?
I mean, if you you guys learn offfrom each other, this is very common
(26:36):
for experiments. We go to conferencesor we have discussions or seminars.
That's when we share information.
Of course, you know,
some information gets shared during coffee breaks,
As we've learned,
But now, I mean,
will ATLAS, for example,do a measurement with toponium
(26:59):
included, or,
you found that it's an effect that doesn'twe don't know.
Can't say.
Oh, yeah.
We can't always say these things.
In general, how do you see us going forward withthese measurements?
(27:19):
Well there is not only quantum entanglementthat we can measure,
there are also lots of other quantum correlations,
like Bell's inequality, as we mentioned before.
So for sure, one of the next
point will be to also discover
these new quantum effects.
I want to give maybe a number.
(27:40):
Just to give you an idea.
Why is it interesting to do these measurements
So we mentioned before the Nobel Prizein physics.
Right.
And it was done by testing
the entanglement and the Bell inequality with photons.
What we do here at the LHC,the measurement
that both CMS and ATLAS did
with top quarks, is about12 orders of magnitude higher in energy than
(28:03):
all of these extremely importantlaboratory experiments.
So when you go so muchhigher in the scale,
there is alreadya fundamental interest of why we do this.
And what CMS and ATLAS did,
at least to me, is a proof of concept
that we can actually performsuch measurements using collider physics,
(28:25):
using collider experiments,
and there is so much room for doing more.So many other proposals,
to measure many other things.
A lot has come up
since then.
And we think we can sayboth in CMS and ATLAS we are
now working on performing these other measurementsin some other parts of phase space with top quarks,
(28:45):
or, for example, with the Higgs boson decay.
And so there is a lot to do.
This is the first time this is being donein collider research.
It was the measurement with the highestenergy ever performed.
At the LHC it was the first time.
It was done before
(29:06):
in colliders with mesons
at lower energies, in particular with B mesons,
but it's a different type of entanglement.
It's more flavour entanglementit's related to other properties of particles.
But never at the LHC,
(29:28):
never with quarks
which are fundamental particles,
It's pure quantum entanglementbecause it's a fundamental particle
Remember the example that I gave with
both of the electrons at other parts of the Universe.
Yeah. This was never done actually.
Yeah.
That would take some effort to go to different parts of the universe.
(29:50):
Well yes.
But in general between two whatwe call free electrons.
Yeah.
I mean it was done with a bitmore complicated systems.
Here, we actually measured the entanglementbetween two quarks which are
let's say quasi-free particles.
So, you have theorists
(30:11):
coming to you, saying,I got some ideas now, right?
I guess you have both been approached by theorists
and different things in quantum mechanics thatcan be measured.
Also though, what we have coming up in a few years,
we're going to tear our experiments apart
and we're going to goto a High-Luminosity LHC.
(30:31):
So actually, we have,a year and a half or so
of runningand then nothing for 3 and a half to 4 years.
And then we start up with brand newbeautiful detectors
made to be able to go at a much higher rate,so we'll have much higher statistics,
will that help?
Will that be of use to you?
We will have more data so we can get measurements more precisely.
(30:53):
So, for example,I mean, as was mentioned before by Giulia,
we have a lot more concepts ofquantum correlations that we can measure.
If you look, for example at Bell state,or Bell inequality,
if we look at the measurement,
in t-tbar,we have to go to a lot more extreme
parts of phase space,to perform these measurements.
(31:16):
And if we have more datain order to do it,
it means that we have more eventsand more statistics to actually be able to
do these measurements because,
of course,we need statistics to make
precise measurementsSo extreme parts of phase space.
Sounds like a great place to go.
(31:36):
But it is
sort of those things which are rare.
It's rare to find something that has this momentum,
this energy,
this mass, whatever.
Those are what we consider phase space.
And yeah, with more statistics.
Even if we're not going to increase energy,because the LHC won't increase
much more,
we are about as high as we can go,
(31:58):
having much more datais a way of also going up in energy
because we can produce those thingsthe more rare things you will see there.
Okay.
Well,I'm looking forward to seeing new results.
I think it's going to be a lot of fun.I think especially because
you've gone into an areathat we haven't been in before.
So congratulations on doing that.
(32:20):
So thank you.
I want you to thank Giulia Negro
From Purdue University,in the CMS experiment.
And also Yoav Afik from the ATLAS experimentand from
Enrico Fermi Institute,as shown on his cup
and you have your beautiful CMS cup here.
And I celebrate outreach.
(32:41):
with my IPPOG cup here.
This has been early morning coffeeat CERN.
It's a podcast by the scientists of CERN
about the science of CERN.
You can find all of our episodeson CERN's YouTube channel.
And if you don't want to look at ourlovely faces, you can also listen to us
anywhere where you get a podcastEarly Morning Coffee at CERN.
(33:04):
Anywhere.
Our editor and producer is Chetna Krishna.
Our executive producer is Jacques FichetStudio.
Ron Suykerbuyk is our technical lead.
Our studio manager is Max Brice,sound engineer by Piotr Traczyk.
Our original theme comes from the Canettes Blues Band
with piano by Wojt "Play it in any key" Krajewski.
(33:25):
Many thanks to Paola Catapano, Matthew Chalmersand Arnaud Marsollier
for all of their great adviceand strategic planning, and a big
thanks to the entireECO team (that's not the Ecological team, by the way)
Rather, the Education, Communication and Outreachteam at CERN for providing us with access
to Wire Chamber Studio andall the help that comes along with it.
(33:47):
Opinions expressed here are our ownand do not necessarily reflect
those of CERN or our colleagues,even though we think they ought to.
My name is Steven Goldfarb, and thishas been Early Morning Coffee at CERN.
We'll see you again next month.
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