Dan: Hello and welcome
to the quantum divide.

This is the podcast that talks about
the literal divide between classical it.

And quantum technology.

And the fact that these two domains.

Are will and need to
become closer together.

Quantum networking actually is
more futuristic than perhaps

the computing element of it.

But we're going to try
and focus on that domain.

But we're bound to experience many
different tangents both in podcast

topics and conversation as we go on.

Enjoy.

Okay.

Good afternoon.

Welcome to the Quantum
Divide, the fifth episode.

Very happy this time to have an
interviewee for our first time.

So Sam will give you a badge for that
which I hope you'll wear proudly.

Sam: I will.

Yes.

He used to be the big H,

Dan: Yes, it will go on the
middle of your head here.

So yeah, we're, joined today by
Sam Samuel, who's the director of

engineering in the Outshift part of Cisco.

But I think we'll just start with
a quick intro Sam, if you just want

to say hello, introduce yourself.

I think the purpose of today is to
talk about, we said the state of the

art, but I think we need to touch on
Qubits in QPUs, the different types

of technologies that are out there.

What you think may be happening
in the market or at least not

happening and what the impact will
be on on networking ultimately.

But yeah, why don't you kick off?

.
Sam: Alright the conundrum I
find myself in I'm not a, I'm not

a deep invested all I've done.

In my PhD is quantum type stuff,
so I'm a newbie to quantum, right?

Let's just put that on the table, right?

So I've had, I've been interested
in this a lot since forever and

over many years, I've seen it
developing and developing, right?

So when I finished my PhD, people
were just about starting to show that

Teleportation could occur, right?

So that tells you how long I've
been looking at this, and we've

come a long way since then.

My interest in quantum started
to be raised again when I saw a

bunch of investment going into
quantum startup companies, right?

So the companies like Xanadu out there.

SciQuantum.

SciQuantum, of course, because it
came out of the University of Bristol.

So we're probably the badge of
the UK kind of thing, right?

But that's not the point.

The real point is that a lot of investment
has gone into quantum computing.

And I guess over the past couple
of programs you guys have discussed

the need for scaling of quantum
computing and stuff like that.

So it's probably not gonna
go back over that old turf.

But the one thing that's still not
really answered is which kind of qubit

technology is likely to succeed, right?

And.

I've been polling the industry
for a while, just two years ago,

we looked at a number of quantum
companies, quantum computing

companies to see where they were.

And they were, they all looked as though
they could solve the problem, right?

So yes, I can get a quantum computer
made out of whatever the material is,

but when we start to network stuff,
then I guess there are going to be some

natural front runners in technology.

Now, which of those technologies
would be natural front runners?

I really don't know.

And that's, and after two
years of looking at it, I was

still no clearer to an answer.

So that's I wanted to see if
anybody else had a view or anything

else is becoming clearer or not.

And by the way, this is not to say
that anybody right now is going down

a wrong technological path because I
don't think we can say any of that.

But it's like saying, is there a mix of,
of technologies there that naturally lends

itself towards networking or that's not
true, towards the scaling of a computer.

I don't know not all technologies are,
shall we say, as easy to interface with.

Superconducting quantum computers require
transduction and that adds something else

in the middle for networking to happen.

Adding something else in the
middle, very simply adds more.

chance of loss, right?

And as we're trying to keep the
system as clear and pure as possible,

then adding anything into the
system, may upset the Apple cart.

So it's that sort of thing that's
been poking my curiosity, I think,

over the past 18 months or so.

Dan: Yeah, it's a good topic
because there is a lot of

different technologies out there.

And you're right, once you start adding
distributed systems in there, then

you're bringing more things into the
system that could fail, basically.

Or just be difficult to engineer
or have dependencies on each

other in terms of being ready

..
Sam: yeah, I also get the feeling
that we're also relearning networking.

So that's the other piece that
that I get the definite feeling of.

So simple tasks of By analogy, we
don't think twice about dropping a

workload into a data center at all.

And the other day I was just musing
over what that, what would that be

if I could just drop a quantum load
into a quantum data center overnight?

Now could I do that easily, but with
any assurity that it would work?

And I came back with a resounding
answer of no, not at the moment, right?

But that's not because it won't be solved.

It's just, I think we're a
little bit ahead of ourselves.

So that sort of made me think,
okay, I need to come back maybe

two or three levels before.

We do understanding how we can make
any of this, these systems robust

enough for that kind of operation.

And that that's where
my mind's at the moment.

No goodness or badness,
I think it just is.

Maybe I'll be, maybe Stephen
will give me some good news.

I don't know, but I'll
leave it at that for now.

Stephen, your thoughts?

Steve: Yeah, I'm more or
less on the same page as you.

The qubit technologies
are changing every day.

We don't even know, if one of the ones
that invented right now are going to be

the ones that's going to survive in 10
years, I think they're going to, maybe

someone's going to invent something
new and that's going to be the leader.

Maybe it depends on the application.

So we might have some applications
using some qubit technology, some

applications, different technologies.

So it's probably going to be a
combination of things and depends

on what we're using the qubits for.

But I think the real problem
right now is it's really just.

Okay.

Firstly, is getting a one quantum
computer to work and making sure

we have an application with quantum
computing in the first place.

This is a bit tricky because, we, so far
it's been something maybe 10 years or so.

And we're still working on that
aspect of quantum computing.

But of course, having the application
that does something meaningful also

means that you have to have large scale.

So maybe these things go hand in hand,
or maybe one comes one before the other.

That's a good, it's a good
question to ask, I think.

Yeah, I think in terms of connectivity
and connecting quantum computers,

it's still such an early stage.

Really, the only things I'm seeing are
preliminary lab results, essentially.

But, building robust technology around
distributed quantum computing is still

completely wide open, in my opinion.

Sam: There is an interesting trend
that I'm seeing around that, which

is when, okay, so from a technology
exploitation angle, it's a bit like

saying, okay, is there sufficient utility
in the technology today that it can

generate revenue for someone, right?

I'd love to think that everybody's
investing into quantum computing

because they just feel it's the
right thing to do, as opposed to

people investing in quantum computing
because they see money in it, right?

And unfortunately, I think it's
the second one we have to prove.

It,

Dan: I think it starts with the people
who think it's the right thing to do.

Sam: But when it gets to us shallow minded
folks, it's all about making money right?

At the end of the day.

But it's more it's more right now
what I'm seeing, so in, in light of

what Steven just said that there's
a whole bunch of stuff that is still

up in the air, is not quite mature,
let's me to say it won't mature.

And it's not to say
that it'll never mature.

Then get that on the table.

But there are a number of companies
out there who are advocating for the

use of quantum computers, even at the
smaller scale that there are, they

are right now, and showing benefits
in terms of some kinds of problems,

optimization problems, and so on and
so forth, that are giving improvements

over the traditional classical approach
to doing the same sort of computation.

And these.

Companies are showing improvement
over the current system.

So that's a good sign.

So that means that, yes, if we
can get to a scalable system, then

you can tackle tougher problems.

But the point is, at least from their
angle, is that even at the stage of the

state that quantum computers are today, in
terms of their own size and capabilities,

they're still producing useful output.

It might be very specialized and niche,
but they're still producing useful output.

I'm hoping that because...

They are producing useful output.

Everybody will start to agree.

Yes, we need to scale them, and
therefore there's more effort put

into the networking side of it
to get that scaling problem done.

But then that still comes back
to the point of which Qubit

technology is it likely to be?

And I have a hunch there's probably
a mix of Qubit technologies

that are mutually exclusive.

And there's a, bunch of
Qubit technologies that are

likely mutually inclusive.

That they are easier to work with and
scale from a manufacturing point of view.

And again, I have no idea which they
are just yet but I have a feeling that

the manufacturability of something
will influence that a great deal.

That,

Dan: here's a question on that.

And we were thinking at the beginning of
this call around the dependency of the

Qubit technology, which is successful
and the development of the networking

technology after that to support it.

Is there actually the way, the way the
networking works or is likely to work

is using photons But that's agnostic
of what the actual computer itself is

using, apart from the fact there needs to
be the transduction that you mentioned.

Sam: That just step back for
a second because it depends on

the materials that you're using.

Over shorter distances you're
less constrained, right?

So it's useful to, to, at this stage,
I think, in where the technology is at,

it's useful to constrain the distance
that you're actually operating over.

In full disclosure, misguidedly, when
I first started looking at this, I

thought, ah, it'll be a few years,
a couple of years, ah, 18 months

before we're throwing, qubits over
large and vast distances, the same

way we throw optical networks today.

And it's, that's not the case.

We're bringing it back to something
which is much more constricted.

And that clearly in my mind,
at least that puts it, you're

looking for a quantum data center.

, what I mean by that, a row of
quantum compute inside a data

center where the distances involved
are at most hundreds of meters.

And it's useful to view it that
way because there are certain other

technologies on the edge of that.

Such as hollow fiber, that could
actually help a great deal in

trying to get the content, the
networking part of it to work.

So there's that part of it, and I think
that's a useful thing to look at cuz you

still have to solve some of the major
problems for networking anyway, even in

a constrained distance type environment.

So that's good.

The other thing is that it
brings out, or it amplifies the

kind of compute architecture.

That will likely drive the network anyway,
and from that you're going to get answers.

One way or another, right?

So what do I mean by that?

That we're still trying to understand
which of the two compute architectures

that are dominant at the moment,
whether it's gate based or whether it's

measurement based computing impacts
the way the network is designed, right?

And there might be benefits
in either or all of those.

So that's something else that I think is
like a little bit just around the corner.

And I see plenty of activity out there.

. In one or other of those camps, the
newest startups I'm seeing are very much

measurement based derivation of them.

So I, like I say, I know I'm not quite
sure how how that will materialize, but

the way the computing is architected
will definitely impact the way the

networking is architected and managed.

.
Dan: yeah, and at the beginning we were
talking about connecting QPUs rather

than talking about connecting computers.

And certainly the, IBM is
the leader when it comes to

investment in the computing side.

Their roadmap shows systems that
are going to have network QPUs.

But you're right, that is
within a closed environment.

And therefore has...

Yeah, potentially the option
to use other technologies.

You mentioned hollow fiber,
that's super interesting.

Could you summarize that?

Could you just talk about that briefly?

Sam: Okay.

So there, if we wish to get the
loss in the fiber down even further,

hollow fibers appear to give a means
of doing that if in a system the

communication aspect of it really does
need not to have any photon loss in it.

Then you really need to have a
system which can give you that.

And so Holofiber would be something which
would be monumentally expensive to to

redistribute over an entire country, but
to do inside a data center over a specific

rack or row would be not so as expensive.

Dan: okay.

So it's, that stops some other
scattering of photons and would improve

the error rate because sending qubits
over a fiber is notoriously difficult

and error rates are very high.

Sam: Yeah but again to send any
information you're not sending

information over the network technically.

If you're, if you've got dispersed
distributed systems and you're

teleporting them, then your real problem
is one of entanglement generation.

Can I maintain and sustain
a sufficient entanglement?

Generation rates such that the
the application that is needing to

communicate sees no interruption.

In in its computation.

So there's two things that we're
trying to there's two things that I

think are trying to be solved back to
this workload nightmare that I had.

So I have a workload.

I put it into the data center.

The workload has got to be distributed
into that data center because no

one QP you can take the load to take
the actual application itself in

distributing it around the system.

Then there's lots of
considerations that need to happen.

Breaking the application or subjecting
the application to dispersal, I don't

think is a trivial task either, right?

So if.

If we look at data centers today, the
workloads are continually shifting

because you're trying to optimize
the amount of amount of money that a

compute platform can raise revenue on.

By analogy then, that means that
a quantum data center would be

doing the same sort of thing.

It's continually shifting its loads around
amongst the available qubits to optimize

how many quantum loads you can take on.

And I don't think that, today at
least, that looks like an immensely

difficult problem to, to solve.

And the network plays a
great deal in that, right?

So it's, I think the two are joined
at the hip, but I don't think the

problems are are without solution.

I'm sure they are, but at the moment it's
like I'm not seeing any clear winner in

Dan: And I hope your nightmares
subside a little bit.

To be having bad nightmares this early on.

I hope you're not losing sleep.

Sam: that.

No, it's not a question of
losing sleep it's a question of

I'm sure Stephen has the same.

The same view of things is like you,
you look at something, you think, Oh,

somebody solved that part of it and you
think, Oh, great, things have moved on.

Then you look at it.

Hang on a minute.

I look at the complete list of
things that I need to solve.

And because I've solved that piece
of it, something else is added

to the end of the list, right?

So the list is not getting shorter.

It's equally as long, if not increasing

Dan: ending.

Yeah.

. Sam: Yeah, at this stage.

But there's that to be unexpected.

No, not really.

Because it's still a very
useful technology from this

point of view, at least.

Excellent.

Dan: uncomfortable using the word
workload because of the connotations

of what it is in the classical sense
and the fact that quantum computing

is more about laying a circuit onto
the, we're at a very early stage of

Sam: Yeah but it is.

Yeah,

Dan: that are put into the systems, right?

Sam: yeah, but a workload is a
connotation of a unit of charge, right?

I'm going to charge you X amount
for this job that you put into the

Dan: It's a job.

Yeah.

Okay.

Sam: job, right?

So and it's the same sort of thing.

So for a quantum system, you're
trying to optimize in two directions.

So you're trying to optimize
in terms of the execution time

that the actual application has
at the same time is minimized.

Minimize both actually, minimize the
amount of time it takes on the system and

then minimize the amount of entanglement
that the network has to generate

to satisfy that application, right?

And if you're really paying
Tetris in a data center, you could

come into all sorts of wonderful
solutions at the end of the day.

Right now, I don't think we're
anywhere near ready for that.

But for sure, I'm starting to see
people think along those lines, which

I think is great because that's just
bringing more reality into what we do.

Dan: And Steve, we were talking
about this previously, right?

Quantum entanglement distribution
as being one of the main, we'll call

it requirements to build any of this
technology on top is reliable distribution

of quantum entanglement in volume.

Steve: Yeah, I think especially
in distributed computing.

needs a lot of it.

So you have to make sure that the
software distributing the algorithms

has that as an optimization factor.

So it's for me, it's really the 2
sided problem is the engineering

side is so difficult and the software
side is so difficult as well.

But that's not to say
it's not going to happen.

I'm completely bored with Sam.

It's hard.

It's not there yet, but.

It's not impossible and it's something
we have to do eventually, I think

Sam: But it's a, it's a.

Here's the other conundrum that I'm, I
don't think it's a conundrum, it's just, I

guess it's a particular view that I have.

Right now, as I look across the
entirety of the ecosystem, I see

the need for more collaboration
rather than less collaboration.

So there are many startup companies
that are actually in need of

talking with others because they
need to figure it out communally.

I don't think one startup can
solve all the problems, right?

Least of all, when it
comes to a data center.

Although some, are trying
to get down that route.

But there are some unanswered things.

There's some really stupid things
that keep coming into my mind as to

whether we need memory or not, right?

So if we're able to have a
completely photonic system.

And you're able to articulate how the
application should be served, and it

can be done all photonically, then
maybe the need for memory isn't there.

But the moment you start to look at it
from a realistic point of view, that

not everything works according to plan,
or there's always some kind of delay

in the system, then memory comes in.

Memory is another area
that I'm just baffled by.

I don't know who's going to have
the right kind of memory at all.

And again, that comes down to the
kind of technologies that are there.

And there's some really, what I would
call, wonderful ideas that are coming out,

in, in how memory can be instantiated.

Some are just basically, I
keep the photon pinging between

two mirrors until I need it.

But even then, at some point that,
that will decode here, right?

And there are others that are looking,
actually looking at the hollow fiber

as a means of constructing a memory.

So there's some real brilliant ideas
coming out from all sorts of directions.

But from a manufacturing point of view,
again, you've got the benchmark of saying

silicon based memory is very small.

I can make it modular.

I can add it into almost anything.

Ultimately, I think even for.

Distributed quantum computer
that tries to take up slack in

the system, you're going to need
memory in some way, shape, or form.

I don't know what that is, again.

I think so.

All right, we know what memory is,
but we don't know which technology

is going to be giving us the best
performance memory that there is.

Dan: Steve, any thoughts on
that, on the memory topic?

Steve: to me, this whole challenge
of building the distributed quantum

computer is like, it reminds me of my
analogy is it's like building one of

these big marble statues, like the David
or something where you have to chisel

away each piece, work on the foot,
work on the hand, work on the face.

And everything is just a block right now,
so we're working hard on each component

harder and harder, but it's, yeah,
so everything is in the novel stage.

You don't know what it's
going to look like yet.

We're still chiseling, but it's the same.

It's the same perspective, what
memory technology will win.

Is it going to be able to
connect with quantum computing?

Is it just something that.

You can store and then you need to, I
don't know, it's, you can't manipulate

well in storage, for example, is it
just a buffer is what's, and if it's

just a buffer, then what can we do?

So many questions that arise just
because we have the memory, does it

work the way you want it to work?

And it's also a big problem, but
yeah, I see it from the, it's

like tackling a big challenge and
everything is open ended, but.

I see promise though, definitely.

There's so many interesting questions
to ask and the unique solutions to that

make, make people interested in the topic.

People like to challenge people
and solve these hard problems.

Dan: The analogy with
David is interesting.

Even if you've got a really badly
chiseled foot and hand and head and

everything, if you squint a bit, it
can still look like David, right?

Perhaps we just need that.

It's that first.

Cut that looks like the shape
of the, of your figure, right?

We don't need everything to
be finessed and polished down

to a perfect surface yet.

That will come.

Yeah, memories are really interesting.

I can't get my head around how how
that's going to come, because it's such

a difficult task to, to capture the,
ultimately you need to capture the state

of the qubit without observing it, right?

Perhaps if you could explain a bit more
about what it is the memory needs to do.

Is it just one type of function
that needs to provide, or is it

are there many different ways of
using memory in a quantum system?

Sam: a lot.

Yeah, there's a
particularly good question.

So typically, in the absence of deep
understanding of the way, at least from

my point of view, because I don't have
that real deep understanding of the way

quantum systems really work, at least like
this, that we're talking about right now.

And you tend to draw an analogy
back to The classical kind of

systems that you have, right?

And then there's the memories
used in a couple of ways.

So one of them is just your
ability to IO anything, right?

So you're storing something temporarily.

And the other one is that I'm moving
blocks around internally in order

that I can perform operations on
them now from my naive point of view.

So this is me just looking at it
from a networking point of view.

I just need something to IO, right?

So if the system is a.

Entanglement based communication system,
then I'm looking to store entanglement

at either ends of the communication link
such that When required the information

can be teleported across the system.

So that's the sort of
naive view I'm looking at.

So I need to store that
entanglement somewhere.

And if it's a temporary thing, then
it's, that sort of lends itself

towards what memory would be.

That's one kind of memory.

The others, what's used internal to a a
quantum computer, again I can't quite,

I can't really put my finger on that.

Because that comes down to the sorts
of computational model you might have.

So again, in my naive understanding
of measurement based computing, you're

entangling a whole bunch of stuff you're
then taking the measurement of it.

So at that point, are you
reinitializing the entanglement?

And if you are waiting for the
next set of instructions to

arrive, is that memory, right?

Or are you continually operating
on a register and the register

itself is memory, right?

So think of it as you,
you're continually adding.

pulses to a block of something
and that block happens to be

memory because that's what, that's
where the computation is held.

So these are all very naive.

Remarks that I'm making, but they're
all, they all trickle down back to

the central point, which is depending
on the computational model, I think

depends on how you structure the
network around it to support it.

Dan: Yeah, that's fascinating.

Steve?

Steve: And from my
perspective, it's about memory.

What is this function is like Sam said,
it's about storing something while you're

waiting for something else to happen.

So you can take it out of memory
and then continue to operate.

So I think there's different aspects
of memory as well that we could

think about is, for example, we have
our computers or laptops have Ram

and they have a persistent storage
and that's just one computer.

So thinking about the algorithms that
we have to run our quantum computers,

could even think about memories.

Within the quantum computer that
potentially don't do everything that acts

as just a long term storage that we don't
need access to the qubits immediately.

So we put them away for
a while, bring them back.

But there's also those like network
aspect memories where those could

be operating in a different way.

Those might need transduction
between solid state and photonics.

Where the other ones I was mentioning
could potentially not need transduction.

So there's different ways to think about
memory from my perspective, but I guess

when we're talking about networks, then
there's that one perspective where you

need to take a photon, bring it to a solid
state or hold the photon, which is usually

harder and then bring the photon back up.

Sam: Yeah.

But I think Steven, I think I prefer
your view of it because it's more.

Let's see.

In this hand wavy way, it's more
precise than mine, because I'm looking

at it from a naive point of view.

But if I look at it holistically in,
in a sense, the networking needs to

know the capabilities of the quantum
computer that it's trying to network.

In that sense you, you really do
need to understand, or we need to

understand, I think, what we expect
from that computational block.

In terms of what's internal memory is.

And what and how it interfaces things
because it, I have a sneaky suspicion

that if we are going for a heterogeneous
network of the future quantum network

of the future, then you're looking
to run the network within the lowest

common denominator of coherence
time that's available to you, right?

And right now we don't
think along those lines.

We do any kind of computing.

It's oh, yeah, just run it in
the interfaces and it all works.

In this kind of environment, I think we
probably do need to think about that at

least this stage, because until some,
somebody of of Stephen's youthfulness

comes up with the answer to just after
I've retired or something, right?

And then yeah, the problem goes away.

But I think in the meantime, we are.

We are needing to look at
the system like that, right?

Dan: Yeah, there's no abstraction.

Yeah, there's no demarcation
between different

Sam: no

Dan: It's...

Sam: not yet, but I think that'll come.

I know Stephen and I have had
offline conversations on this.

Good grief, maybe about a year
ago around standardization.

And I think that's where those
conversations are likely to appear.

So in other words, Dan as we see,
as I hope to see, some technology

start to really progress in terms of
how we can engineer a real system.

At scale, right?

So I think we can engineer any system,
by the way, is the at scale part of

it is the critical caveat to all of
this that you'll start to see more

emphasis on the standardization as
well, because you're trying to make

sure that interfacing works out.

Easily,

Dan: yeah, we've spoken a lot about
teleportation maybe we could just talk

about that for a minute as it seems like
that's the kind of default requirement

that you've, that you're thinking about at
this point in time and how the different

QPUs or computers will be talking to
each other using that entanglement.

On the network.

So is there's also the idea of
sending flying cubits across

the network and capturing them
then, using transaction somehow.

Do you reckon there's going to be multiple
ways that the network is going to work?

Depend on the application

Sam: I think at the moment we gravitate
towards the thing that we think we

can get to work the most, right?

So right now, I think the
discussions are around teleportation

because it's, I think it's.

Probably more tractable for the moment.

Now, is that the final solution?

I don't know yet to do the other requires
us to have a great deal of confidence

in our ability to encode qubits, I would
say And then not lose, or not suffer

a 3dB loss anywhere in the system.

Dan: lose less than

Sam: All right.

So you can recover it.

So I'm pretty sure, I know, I think
Steven and I have spoken to many very

clever people in this field, that the
quantum, quantum error correction can

really help in almost all aspects of
quantum networking and quantum computing.

But getting down to tractable
solutions of those, I think is

again, Another hurdle, right?

I'm not sure whether it's David's
hand, foot, shoulder, arm, or

head, but it's one of those blocks,

Dan: It's an appendage.

Sam: Yeah, it's an appendage.

Let's make sure it's
not a sore one, right?

So it's one of those.

But yeah, maybe Steven you've seen
reports of this in the learned journals

better than I have, but I haven't
seen applications as in experimental

applications of large quantum error
correction applied to something yet.

I know that theoretically they've
shown it, but I haven't seen

anything, anybody doing it.

Steve: Yeah, I think from what I've
seen, error correction has been done

very recently in a quantum computer
setting, but error correction and

communication, I haven't seen yet.

Sam: So that, but again, on the flip
side of it, if we constrain the distance,

I'm hoping that we'll see that realized,
which, which comes to the guidance

that, you know, that that I think we
want to give ourselves, which is no

don't apply overkill to the constraints.

It's okay, to make sure
that the technologies.

It's in its infancy still, it will be
for quite a while, so just make sure

we give it a nice playpen to work in
so we don't make it cross the main

road in the first day, that would be a
bad idea something along those lines,

Dan: Keep it on a lead.

So I was reading this paper the
other day it came out of a university

in the Netherlands about the link
layer protocol for quantum networks.

Obviously, this is all
purely theoretical stuff.

I'll put it in the I'll put
the link in the show notes

if anybody wants to read it.

But what do you think about the I'm going
to just describe how they've Looked at

classical networking layers and compared
them to how a quantum network could build

Link state if you like or state across
a network using the same kind of concept

So what they do is at the physical layer
If you think about the layers in the OSI

model, right the physical layer They call
it Attempting entanglement generation.

So this is where your physical
layer, you're sending lots and lots

of photons and you've got whatever
process is to capture the entanglement

and store it ready for use.

And then the link layer, they call
it robust entanglement generation,

where there's an additional layer
of control, which ensures that the

entanglement is usable, controllable
and, I'm ready for the next layer, and

then for the network layer, they talk
about long distance entanglement, which

I guess is the analogy to layer three
networking across the network it's

maybe more effective and would need
real quantum repeaters in the way or

something to make a longer connection.

Sam: Quantum repeaters, ooh,

Dan: and then at the high level,
they call for the transport

layer qubit transmission.

So that's when you've actually been
using the entanglement and all of

the network, whatever it looks like.

Sam: it's Yeah I guess this
is one of the QuTech papers,

Dan: it is QuTech.

Sam: Sometimes I get the feeling
that the reason we layer things is

because we humans are feeble, right?

We have to be able to
complementalize stuff in order

to understand anything, right?

So we give it layers, and it helps us give
us the structure and so on and so forth.

So the interesting thing with the
layer, as you described it, as

you go upwards through the layers,
then you're getting further and

further apart notionally, right?

So we can do maybe a short link, but if
you want to go over many distinct links,

we need to have a repeater with them.

So if we look at the way we look at
network layers today, it's okay, you

don't go all the way up to the top
layer, you're actually repeating and

maybe layer one, layer two, right?

That kind of thing.

All right.

And because entanglement is not
your typical network, it's not

packet networking, as we see today.

Because when you network something
over any kind of distance, there's a

path that you take, and the path has
a number of hops and stuff like that.

And eventually the information, when it's
transferred, still takes a number of hops.

But in an entanglement based network,
you're breaking the rules a little bit

because you're making everything adjacent.

So if the two endpoints are adjacent...

Then there is technically speaking,
there isn't the network that doesn't

materialize in the middle anymore and
plays no part in the transmission, right?

So then that means the way we manage
networks across a large area network

is going to be very different from
the way you manage networks today.

Dan: Yeah.

You won't be counting packets
that are going across the network.

You, all you need is to ensure
there's enough entanglement so

that the teleportation can take

Sam: Yeah.

But that, but the interesting thing
here is this, and this is, and

then we're gonna go off into the
tall grass a little bit, right?

And all I've got

Dan: all right.

Sam: all, I've

Dan: why we're here.

Yeah.

Sam: Yeah.

Dan: Mr.

Get your strummer

Sam: yeah.

Yeah.

Find the ball in, the tall grass.

So in, into the tall grass.

So here's the issue that
I think we have, right?

It's right that people conjecture that
we're going to have a quantum internet.

I think that's absolutely true.

When you start to pick away at the issues
that are around quantum computation

and quantum networking, you quickly
come to the realization that actually

quantum computing is a kind of high
performance computing, or will be a

kind of high performance computing.

It's not gonna do general stuff, right?

It'll do very specific things.

Or at least for a good while, right?

Which is, which then calls into
question, why would you be doing

anything over a large, longer distance?

So we do all of our high performance
computing in data centers today, right?

And that's accessing it.

You can do over a classical
network and the rest of the

good stuff that goes with it.

But to say that we would be having quantum
networking over increasingly longer

distances, I think is that's that's,
that requires a lot more thought before

we head in that direction, I think.

So it's a bit like saying, I'm
going to run a, an application

where you are down today somewhere.

I guess towards the south coast and
here I am near Cheltenham and I'm going

to suddenly need to have my quantum
algorithm run on your machine, right?

I'm going with all the problems of
making sure that works and it's just,

oh, you're asking for trouble, right?

So I don't think that's naturally
the way to go but I don't have

a good alternative for you.

Dan: But perhaps in the security
space, there's going to be more

Sam: Yeah, in the security
space, that's true.

But then if you're teleporting, it's
a different security paradigm that

you have, it's just a very different,
you're not sending information

over the network anymore, you're
teleporting information, right?

So it's a very different paradigm.

And I think there's mileage in that.

But again, you've got to make
it all reliable and all that

kind of good stuff, right?

So if so, let's see if I can drag
ourselves out of the tall grass.

If the quantum computing is
about doing computations.

That you can either improve the result of
over a classical system or do computations

that you can't classically do.

Then you're really looking at
mathematical co processing kind of things.

And that's a specialized form of
computing that is, will be happening

in a single space more than likely.

A data center with a row in it is
more likely to be the result, I think.

And going over a distance, I,
I think we're a long way from

that, but that doesn't mean
saying we shouldn't aim for it.

Absolutely.

But I think there are plenty of problems.

On the list to solve before we
get to those, and then to your

point on the quantum repeater.

Okay, a quantum repeater
is a small computer.

Can you make them small and self contained
enough that you can do the relay?

Yeah, I think you can.

But it's back to the first question.

Okay, which are the gate technologies
that you think will dominate?

And can we make a repeater out of them?

That's cost effective.

Don't forget the cost of it.

Dan: we did one of our previous course
talking about cloud and the availability

of cloud services, quantum cloud services
to late perform of computation remotely.

I think that is going to
remain as the main method for.

Utilizing these types of services, because
if you have a problem that is classically

difficult, or it takes many months, years
to perform the computation, and a quantum

algorithm will be able to improve that
for you, then it's not too difficult.

In fact, a lot of the software elements
are out there already to be able to just

do that remotely and get the results back.

There are many companies out
there offering this already.

Sam: But Dan, here's the thing.

This is me coming from an old guy, right?

So here's the thing.

We're still, in that very sentence,
we're still judging quantum

computing classically and quantum
networking classically, right?

We're coming at it from, we view networks
like this, and therefore, we tend to

try, we tend to layer it so we have
the analogy between this network and

the current network and so on right?

Whereas in reality, it will probably
go off in a totally different

direction and give you unexpected
results once it starts to get used.

And I'm being pretty honest with
you, my head is not in that space.

I don't think it'll be my
generation which looks at that.

It'll be the following,
it'll be Stephan's.

Generation which looks at that
and this is why we're doing

communication at a distance using
quantum stuff because of whatever

Dan: Yeah, I was just building on the
high performance compute kind of topic.

Ultimately, that's an extension, what's
out there now is going to be developed,

continually developed over the next few
years is utilising quantum computers

at a distance and therefore extending
your ability to use an equivalent

niche high performance computer without
needing to invest in it yourself, right?

Sam: Yeah, I can see there's there would
be an established market for this so

so back in my youth there was an awful
lot of noise when I first did my PhD

around chaos theory and The ability
to use that in financial markets to

predict things or someone Automated
trading and all this kind of nonsense,

and there was but then everybody did
it, so there was no longer an advantage.

Everything just moves up one.

And I've got a sneaky suspicion that
quantum computing will be the same sort

of thing, that the financial markets will
see a need for it, because they can see

some benefit out of it, and that would
be great, because that pulls through the

industry, and then you're going to have
the mainstream use occurring elsewhere.

Or something like that, right?

So it will be a first mover
advantage for somebody.

It'll drive the commercial need for it.

And in driving the commercial need
for other commercial things will

be found that you couldn't do.

And then that becomes
interesting at that point.

But again, is that going to happen
in the next two or three years?

I don't think so.

I think it's going to be happening
for Maybe charitably ten years away.

Something like that.

Dan: I've done my best to not ask
people to look into a crystal ball

in these podcasts because I think
that's unfair because there's

Sam: Yeah,

Dan: so many variables.

So

Sam: I wouldn't trust my view.

I trust Stephen's view more than mine.

I think in this because he's
going to be around longer.

Steve: Yeah, let's see the timeline
from my perspective is it's my, I

think it'll exceed both our lifetimes.

Until it gets to this stage where,
it's an everyday tool for everybody or

at least, scientists or academics or
something that we can reliably go to

quantum computing, answer questions.

Maybe that's maybe, okay, maybe
not that long, but I think 10 years

is a reasonable number to say.

That's when it'll start making an impact
on academic research, maybe another 10

years before it's affecting the industry
or, the economy, the corporate world.

Dan: Based on that, we're getting
to the end, but I just thinking

about what's happening in the
macro environment with quantum.

So moving away from the
technology for a minute here.

The fact that you're, we're talking about
that kind of length of time, and the fact

that there's a lot of investment going
in has been a real spike in it recently.

Any thoughts on when do you think there'll
be a bubble coming and then maybe a,

Sam: Oh, Jesus.

Dan: a drought?

Do they still call it a drought

Sam: yeah when does anybody
not said no to a bubble, right?

It's oh, come on guys, we can
hype anything in this world.

And why would this be any different?

Dan: I think a quantum
bubble is a different color.

I think that's

Sam: No, it is maybe there or maybe not.

It depends, right?

So super bubble

super pose bubble, at least.

So you're asking about human
nature, Dan, you're not asking about

Dan: No, it's worse than that.

I said I wasn't going to ask
predictions and I've just

asked you to make a prediction.

Sam: Yeah, I know.

So about a bubble of all things, right?

So

Dan: it's impossible to say.

We're definitely seeing some

Growth

Sam: I, but I can't give you an answer.

I can give you my preferred answer, which
is I sincerely hope there's not a bubble.

Because a bubble can really get
in the way of actually coming to a

tractable commercial solution, right?

And and you want to remove the
carpetbagger effect, right?

So think of Bitcoin, right?

That was a huge bubble.

And that did...

Web three a huge disservice.

Blockchains and all that technology
is a useful technology, but it got

completely distorted by the need for
bitcoins or some kind of electric

electronic financial instrument that can
be based on a different kind of currency.

Right?

But the underlying technology that's
being used is still useful, But it got.

Completely mugged on the
way to the forum, right?

And I really want to avoid
the same thing with quantum.

I think quantum is going to
have an immense impact on us.

Maybe not in my generation so
much, but maybe in Stefan's.

I think it probably will.

And it will.

And if we if it fulfills his
aspirational hopes of being able

to do more intense computations,
That actually conclude, right?

So they complete in , polynomial time.

Then I think that's going to be
a good thing for humanity, right?

So we've got some tough problems
coming up, I think that'll be the case.

But putting hype in the middle of it
and bubbles is just the wrong thing.

Dan: Oh yeah.

It seems to be in our
nature though, doesn't it?

This is turning into a
philosophical conversation

Sam: It is,

Dan: about the human race.

But,

Sam: yeah.

It is turning into a
philisophical conversation.

But from a researcher point of view, you
want to get to an honest answer, and I

think hype just doesn't give you that
opportunity to get to an honest answer.

Dan: and it's the, the fact that
the academic successes can be.

Blown up out of all proportion sometimes
not that doesn't undermine any of the

academic successes in any way whatsoever.

It's just that sometimes the view in
the public eye is distorted as you said.

So I think that's what
needs to be avoided.

If that's the case, then there's
no chance of a bubble, certainly

in terms of expectation.

Steve: Yeah.

I would make it one comment.

I think the reason there is so much hype
is because there is a lot of potential,

but it's hard to access that potential.

Timelines don't exist for
hype, hyping up things.

It's just now or never.

But in general, I think there's
a good reason why there's hype is

because there is a lot of potential.

But one thing I'm noticing,
though, at least recently is the

hype is becoming more realistic.

So maybe five years ago, the hype
was different than it is now.

And yeah, and I think that's a good sign.

People are becoming closer to
the planet, bringing the clouds

a little closer to Earth.

Thanks.

Dan: Great.

Okay.

I think that's it for this pod.

Thank you very much, Sam.

It's been really good.

To chat with you.

We might even invite you
back if you're lucky.

Sam: Thank you that, that's
buoyed my confidence.

Excellent.

Yeah.

All right.

Dan: We'll have to think about it.

No, honestly, it's great conversation.

And yeah.

Bye for now.

Sam: Alright.

See you next time.

Dan: Thank you, Steve.

I'd like to take this moment to thank
you for listening to the podcast.

Quantum networking is such a broad domain
especially considering the breadth of

quantum physics and quantum computing all
as an undercurrent easily to get sucked

into So much is still in the research
realm which can make it really tough for

a curious it guy to know where to start.

So hit subscribe or follow me on your
podcast platform and I'll do my best

to bring you more prevalent topics
in the world of quantum networking.

Spread the word.

It would really help us out.