Hello, and welcome to this episode of the
Physics World Weekly Podcast,
which is sponsored by the National Physical Laboratory.
I'm Hamish Johnston.
The National Physical Laboratory
or NPL
is The UK's
National Metrology
Institute.
It provides cutting edge measurement science,
engineering, and technology
to underpin prosperity and quality of life in
The UK.
NPL bridges the gap between research and industry
by providing the measurement science,
facilities,
and expertise
needed to accelerate innovation
from lab to market
across various sectors.
One of those sectors is quantum,
which we're going to dive into today.
I'm joined by Tim Pryor, who is quantum
program manager at NPL,
and by John Devaney,
who is NPL's
quantum standards manager.
Hi, Tim and John.
Welcome to the podcast.
Hi there. Great to be here. Hi. Pleased
to meet you again.
So, Tim,
in October, NPL became a founding member of
NMIQ,
which is a global initiative to standardize metrology
standards
for quantum technologies.
What is NMIQ,
and why does NPL see it as crucial
to the success of the quantum industry?
So NMIQ
is a, an initiative,
between some of the world's leading national maturity
institutes to work on prestandardization
research
leading to standards in the future.
So quantum
is often very complicated and has huge scope
of application.
This makes it,
really difficult to understand the technologies
sufficiently well to able to just standardize
things. Faced with this problem, we work closely
with The US first and then grant you
with the other g seven,
members and Australia
to develop a framework
that we can work together on standardization
where there's a common
strategic
interest. The thing is because quantum is so
broad and so difficult,
no one country could do it all. So
we have to work together on these sorts
of issues.
And, Tim,
NPL has very, very strong
connections with industry.
What is industry telling you about what it
wants from quantum standards?
It's a that's a very interesting question.
Industry tells us that
you really need to work differently nowadays with
standards.
So emerging technologies traditionally
have, had standards evolve gradually,
probably in a serious type of effect.
In reality now with the world being so
global,
information is shared almost instantly amongst everyone, and
so everyone wants the answers right now.
So if you want to make sure that
your technology
is part of the standardization
process, which leads to adoption
and use, then you've got to be working
in this area in parallel to the innovation
being developed.
The thing is that innovators are usually so
busy doing things,
you know, like building the things they're trying
to get standardized, so they don't always want
to get involved.
And this is where organizations like MPO can
actually help them in the by expressing what
they need to happen, we could look after
them for that. In The UK, we've gone
a bit further than that, and we've been
running a pilot,
for,
DCIT,
called the UK Quantum Standards Network.
And that is about bringing together all the
government agencies that were interested in in in
standardization of quantum technologies
and sort of find make a more coordinated
approach, making it easier for industry to get
information,
and making it easy for us to actually
work together for a common interest.
It it must be really difficult though, Tim,
because quantum technology is evolving
so quickly.
What are the challenges of defining
standards,
for the quantum industry in such a fast
paced environment?
It's it's very, very challenging. And, actually, a
lot of the work we do in MPL
is to talk to people outside to try
and understand what their future requirements are going
to be so that we can do the
research necessary to make those standards in the
future.
And, of course, this comes back to the
NMIQ thing. We can't do it all alone.
And
so we speak to all our sister organizations
around the world to get there and and
to put onto,
how this might work and what we need
to work on.
But it's it's it's an amazing thing, really.
So
in metrology, we use quantum technologies for doing
exquisite measurements,
and that's turned around on its head now.
So the ability to do that means that
we can really truly input into the evolving
quantum technologies.
And that knowledge now that we've developed over
decades of use is now becoming incredibly relevant
to people in helping people understand
what they have and how you compare something.
I mean, some really interesting examples is, you
know, if we
think about the application everyone talks about, quantum
computing,
and people say, how do you compare one
computer to another?
That's an incredibly difficult question.
There are so many different types of quantum
computers,
all in theory there to do things in
slightly different ways. If you can find a
methodology for,
characterizing one computer, that might not be very
good for another type.
So it's incredibly difficult, and it's a real
big challenge. Hence, you have to work together
collaboratively to come up with these answers.
And I suppose it's particularly difficult with quantum
computing because we don't know
which
type of qubit
will ultimately
be used in, you know, sort of quantum
computers of the future. And indeed, it might
be more than one
type of qubit. So it must be very
difficult to,
well, I suppose keep up with the development
of qubit technologies and and come up with
with ways of evaluating them.
Very much so. It's, you know,
the the question of which qubit is best
or
how do you compare different qubit modalities
is a really, really difficult question, and it
can keep, metrologists
talking in a pub for days and arguing
about it. But in reality, what we do
is we take it right back to the
fundamentals of the physics side of it and
try to truly understand the mechanism of how
these things are working.
And then we try to
give that information to the people who are
using these qubits,
in a way that's useful for them to
understand how they might want to, for example,
control material quality, which could affect how a
qubit, work.
But this again, with MPL does quite a
lot of work in qubit technologies, but not
in every type of qubit. So then we
collaborate with, you know, The US, Japan,
Germany, etcetera
to get their input so that The UK
can access that knowledge,
and then our collaborators get the knowledge from
The UK as well.
And and John, I wanted to bring you
in,
and talk about quantum sensors,
which,
they they seem to be a fairly advanced,
quantum technology with some commercial products
available today.
What metrology and standards are required to create
high quality
quantum sensors?
Yeah. You're right. That there there are products
on the market already, which are using quantum
phenomena.
But on that question of what standards are
required, there are two sides to that. One
is that quantum sensors are more sensitive, more
accurate, and more useful than existing sensors.
For example, magnetometers for monitoring brain function, drive
emitters for mapping underground resources, spectroscopic
photodetectors
for assessing
gas leaks.
And what matters to those buying the sensor
is its performance,
not that it's quantum.
And in that it's in that sense, standards
are needed to extend,
the the standard standards range that already exists
down into the end of these,
finer and finer details.
But on the other hand,
quantum sensors can only be built with components
and subsystems
that are themselves tested and found ideal for
the task.
Iron traps, diamond substrates with nitrogen vacancies, NV
centers,
superconducting quantum interference devices, SQUIDs.
These also need standards.
So we are approaching it from both directions.
We are helping characterize the the quantum devices
and the quantum characteristics,
And we're helping work out how it is
that you actually,
measure some assess something that is measuring something
more accurately than anything else can, where there's
nothing to compare it against.
And, NMI is like NPL
are are doing things like working out how
how to characterize single photon detectors.
The the only single photon detectors can detect
single photons.
And I I wanted to ask you about,
single photon detectors and sources,
in light of quantum cryptography, which is another
quantum technology that, I mean, I I suppose
you can say it's fairly mature. There are
commercial
systems available.
And in those in that technology, it's really
important
to have photon sources and detectors
that are high quality
and secure.
So how is NPL
supporting the development of quantum cryptography?
Yeah. So sources and detectors in themselves are
are not secure.
It's the way the system is built around
it that that creates that security.
And that is one of the,
one of the aspects of
the performance of a QKD system
that is potentially vulnerable,
to outside attack.
We've, led the way in characterizing QKD systems,
the boxes that are, as you say, are
already on the market.
QKD, just to elaborate, is a way of
generating cryptographic
keys that are unbreakable because they're intrinsically random.
They use the randomness of of quantum physics.
They do it by generating
pairs of photons that are randomly coded.
So there's two levels of randomness going on,
usually by polarization.
And then the process can't be intercepted if
they are single photons
without destroying that information, without
the two the sender and receiver knowing that
there's someone trying to break in.
So like you say,
the sources,
but even most of the detectors,
are a are a point of vulnerability
because you can you can blind,
the,
the detector
by by shining a put a brighter source
into it and then
use your own source to, to spoof the
system.
That's only one. There's other vulnerabilities
like, they don't actually use single photons. And
at this point, they tend to be small
bundles of photons. But if they use too
many, it's possible to split enough of them
off
and and,
and join in on the the key,
key reception.
So we went through all the potential vulnerabilities.
I say we, not me personally. I'm not
allowed in the lab.
We went through all the potential vulnerabilities that
had been identified in QKD,
and we tested
we tested existing systems
against them. And we and we worked out
as
the the sort of criteria that would be
needed in the standard, And we took that
into Etsy,
for the building of their QKD sis
standards family.
And and, John, Tim's already touched a little
bit on the need to
develop performance metrics and benchmarking for quantum computers.
And I understand that NPL is leading, an
initiative,
in that direction.
Why do we need these metrics, and and
what are the challenges in creating them?
There's there is more than one initiative underway.
And the one that I I closest to
is the way that it's been brought into
the standards world.
It's too early for,
full standardization,
but there is a there is a there's
a real demand from the potential buyers of
quantum computers
to know what it is, what are their
strengths, and how do they compare one against
the other.
But that is far from
a a simple question.
It's not a simple question with conventional computers,
but it's even more difficult when we have
no universal
error corrected quantum computer. As Tim said, there
are
a
a number of platforms,
including superconducting qubits,
ion traps,
that are under consideration.
In the early days of attempting to benchmark
them,
it was suggested that you could simply count
the number of qubits and people will still
put up graphs
and say, my computer has
48 or a 150
cubits in it.
And when it was it was realized that
in terms of computing power, that wasn't enough.
They moved to gate depth. How many how
many gates, how many processes
could your quantum processor go through before it
lost the information?
That too is too simplistic.
And so,
we're beginning to look at,
at at more multidimensional
aspects
to hardware benchmarking.
And at the same time,
I'm trying to answer the question, if performance
is what matters,
surely, it's how quickly and how effectively
your quantum
processor
can do a particular task.
That, it turns out, isn't as simple a
question as you might think either,
partly because quantum processors are part of a
stack
in in a similar way to telecoms,
and the error correction is happening in a
multitude of different ways.
But we're we're attacking that one as well,
and and we're bringing the answers to these,
these researches
into the standards, particularly in SanSan, like the
European standards bodies,
and I see IEC ISO, the global standards
bodies, where they're doing
early stage standards. They're doing technical reports on
the benchmarking
systems that people have have come up with
already.
So so John and Tim, I I did
my PhD many, many, many years ago,
and I became a science journalist. But I
often think about, you know, sort of an
alternative universe
where I could have done something else.
And one thing that I've always found appealing
is the idea of working at a place
like NPL.
I mean, it just sounds like,
well, it doesn't sound like it. I know
that people there are doing
a vast, you know, sort of variety of
really interesting research and working with industry and
developing lots of,
of of new technologies.
So, you know, if if there's somebody out
there who's just finished a PhD,
How would you advise them in terms of,
pursuing a career at NPL?
What's available?
So I think one of the things to
first say is that measurement metrology
underpins almost everything everybody does. So there are
lots and lots of fields of interest that
you can you can work within. And as
I mentioned, at the beginning,
we've been using quantum for doing really, really
amazing measurements for a long time.
So we called that quantum metrology.
And that knowledge has led us to be
able to do metrology
for quantum.
So this is basic fundamental
science. So if that's what drives people, there
is in these emerging technologies,
there's a requirement to do fundamental physics.
But
as you develop that, you get to play
with all the applying,
uses of that of that technology.
So we get to work in lots and
lots of fields,
really help to enable things to actually really,
really happen. So exposure
to lots of brilliant people around the country,
around the world, it's an it's an amazing
opportunity for people.
I would
add.
One of the things about coming here to
NPL so like like you, Hamish, I did
my PhD, and then I went off and,
I actually worked,
for the, Institute of Physics Publishing.
That's my that's my first foray into,
public publishing.
And it suited me down to the ground.
I really liked my time there, and it
suited my way of working.
Coming to NPL,
having been there and having been in the
standards world for
twenty years,
that what Tim's talking about, working on metrology,
it really suits people who not just do
proof of principle, which is largely what doing
the PhD is, but love
getting things down to
that nth degree
of of precision,
which which is a is a very
different mindset from you'll find almost anywhere else
in the world.
But that doesn't mean that's everyone at NPL
because I they wouldn't have employed me otherwise.
There there there's lots of different roles,
within NPL
other than working on
metrology
itself.
And I'm I'm pleased that I've been taken
on as a standards expert rather than
as a an experimental physicist.
And and I I should say that I'm
guessing that it's it's not only people with
PhDs in physics
that you're looking for.
Yeah. We're we're we're
we're looking for all all people. And in
fact, we have apprenticeship schemes where,
you know, we we take people in and
develop their skills. Engineers are really important.
These people are sometimes
more difficult to find than the PhD
people. So there's lots of opportunities, but you
need the support around it as well. Need
the, people who need to understand intellectual property.
The people who manage these highly complex,
projects, especially when there are a lot of
partners,
etcetera.
But I think the I mean,
it's now quite recognized that
you need to invest in this sort of
infrastructure,
you know, this measurement capability
in order to actually
allow these things to come to market, to
give The UK the opportunity
to have both growth in the GDP, but
also look after its, security.
And it's really good because The UK's national
strategy
quantum actually recognizes this and talks about it
as a really important mechanism.
And I think that's something that's really important
because
metrology institutes
have been the unsung heroes behind the scenes
for
decades and decade developing capability that enables
trade,
enables safety, enables so many things.
But because it happens
seamlessly,
usually,
then it's just invisible to most people.
But now people recognize with these very complex
technologies coming to market that for those to
happen, you have to have good metrology.
And Tim, we we've spoken a bit about
NPL's connections with industry, but I would assume
that you have very strong,
connections with the academic world,
in physics and and other related,
subjects. Is that right?
Yeah. I mean, we again, we have we're
a reasonably big laboratory,
but the amount of questions we get asked,
you couldn't answer them all yourself. And so
MPL doesn't go out there to try and
reinvent what other people have done. It goes
out there to try and collaborate with the
best people around the country.
In, in the quantum side, that will be
with the quantum hubs,
but people outside that,
international,
academia, etcetera.
We've tried to identify where we have gaps
in our knowledge or The UK has gaps
in its knowledge, and then we try to
collaborate with the people who have those skills.
And
I just wanna ask both of you,
what, you know, what do you find most
exciting about working
in
quantum
metrology? Is it is it the the the
pace of change and, you you know, the
always having to keep up with the latest
research? Or
is it just the novelty that, you know,
these these
esoteric
concepts of quantum physics can be
turned into
technologies? What, you know, what what gets you
guys up, in the morning?
I'd go with the first one. It's, it
it's remarkable. I mean, I've my background was
in optoelectronics
and communications.
And back in the nineties,
you would go to conferences every year, and
they would
be making promises which were slightly better than
previously. But there was no there was nothing
groundbreaking
about it. The physics was well known, and
and they were really just solving engineering and
manufacturing problems,
which isn't easy, which is why I don't
do it. That either.
But now
the the real progress and when one of
the areas within quantum where
progress has been massive in just the last
two or three years
is in, distributed entanglement
where the the the test
three years ago,
the the first tests that you could send
an entangled photon
out over,
say, 15 kilometers of fiber and
and measurably still be entangled
had just been done. And now there are
test networks all over the world,
which are getting ready for product
to make to use quantum entanglement in in
in networks at scale.
That that sort of pace of change is,
quite exciting, really.
And what about you, Tim?
So for me, I mean, it's it's truly
a privilege to be part of working with
so many talented people either at NPL or
in academia and industry in The UK or
international.
You get to see so many different
people. You get to see so many brilliant
technologies.
Last week, I was at CERN.
You know, you get exposed to the things
that you you know, when you're at university,
you only ever dreamt about getting involved in.
And yet
through metrology and through working with a an
organization that's very international,
it's amazing what you can get involved in.
Well, that's great. Thanks. Thanks, Tim and John,
for coming on the podcast,
today.
No worries. Thanks, Janesh.
That was NPL's Tim Pryor and John Devaney.
Thanks to both of them for a fascinating
conversation.
I'm Hamish Johnston, and our producer is Fred
Isles.
This podcast is sponsored by the National Physical
Laboratory,
which retains copyright on this episode.
NPL is The UK's
National Metrology
Institute.
It provides cutting edge measurement science, engineering,
and technology
to underpin prosperity
and quality of life in The UK.
NPL bridges the gap between research and industry
by providing the measurement science, facilities,
and expertise
needed to accelerate
innovation
from lab to market
across various sectors,
including quantum.