- [Todd] Thanks, Carl for the introduction
and good morning, everybody.
As Carl mentioned, I'm
from the Physics Department
and the main objective of my talking here
today is to share with
you that quantum computing
and, more broadly, quantum
information research
is actually a cornerstone
of the Physics Department
here at UMBC, and
there's a large number of
faculty and a very large
research enterprise
both experimental and
theoretical going on in
the physics building
just on the other side of
campus here, if you
want to learn more about
anything I'm saying, you
can just go to our website,
search on quantum
computing, and you'll see
everything I'm talking about.
Okay, so in the physics
world, we're what's considered
a mid-sized department,
we have about 20 regular
faculty, 10 research faculty,
roughly 50 PhD students,
and about 150 undergraduate majors.
Our research areas in the
physics department are
four-fold, so we have research
in atmospheric physics
and astrophysics, as well
as condensed matter physics
and what I'm here to talk
about is our research
in quantum information science.
So we have five faculty
members doing research in
this area and before I
get into their specific
areas and what they're
working on, I wanted to take
a step back and tell
you sort of an overview
of quantum computing
maybe a little bit from
a physics point of view
so the history of this
field, roughly speaking,
goes back to the early
1980s, and there was
a physicist named Richard Feynman who was
actually trying to simulate
a very simple system
of a few electrons
interacting with one another
so picture the little particles colliding
and where will they go,
and how will I model this,
and what he found was
after he got up to a size
of more than a few electrons, the problem
became essentially impossible
to simulate on conventional
computers, and the reason,
as Andrew mentioned earlier
was because the electrons
need to be described
by quantum states, there's
this 2 to the N scaling,
and the problem gets
very complex very quickly
due to these quantum effects.
So, Feynman being the
very smart guy he was,
He sort of turned the
problem around and said
Okay, let me imagine I had a computer that
operated based on these interesting
quantum effects what could it do?
And, so to make a very long story short,
over the last 20 years or so,
what we've found is that these computers
would be very good at quantum simulations
simulating complex
systems, quantum chemistry
and so on, as well as some very specific
algorithms, one known as
Shor's Factoring Algorithm,
which has to do with
factoring huge prime numbers,
very relevant in encryption
and data security,
Grover's Search Algorithm,
which has to do with
searching unstructured databases, and
finally, quantum supremacy,
which is sort of a hot
topic now, we're actually
pushing toward demonstrating
systems that demonstrate
a clear advantage over
classical computing systems.
What's going on with
quantum computers from a
physical point of view?
Well, there's kind of
a principle elaborated
by Rolf Landauer and it's a
very simple statement that
information is physical,
and it's a seemingly
simple statement, but it
actually has very deep
philosophical and physics implications
and roughly speaking,
what this means is that
it's not enough to think
about zeroes and ones as
abstract quantities that
are just sort of out there,
these have to be represented
by physical systems,
processing the information, storing it,
deleting it, this takes
energy, this takes work.
There's entropy involved.
These are physical systems that have to be
described by the laws
of physics, and so in
one regime we have classical
computing, where we have
classical bits that are
represented by big classical
objects that obey the
laws of Newton and so on,
things like wooden beads on an abacus,
all the way to large
voltage poles representing
the zeroes and ones in your cellphones,
on the other extreme, the
idea with quantum information
is what if I can represent
true quantum systems
to encode this information?
So what if the information
is represented in the
form of single atoms,
single photons, and so-on.
And in that case, as
Andrew, I think described
very well, we have this
idea of a quantum bit,
or a qubit which actually
is what something is known
as a super position of zero-one in a very
abstract sense it's as
if it's zero and one
at the same time, so this
leads to concepts like
entanglement or correlations
between bits that
are simply stronger than classical physics
allows and is essentially
at the heart of the
power in quantum computing.
So, from a physics point
of view, it all comes
down to what physical systems can I use to
represent these qubits?
What do I have the tools and technology
in the lab to actually
build and work with these
tiny little systems to
implement these qubits
and so there are a number
of platforms currently
being investigated today,
a few are shown here
the first is what we call spin, so if
you picture a little top
spinning one way, that
would represent a zero,
spinning in another that
might represent a one, and I can have
superpositions of those
in quantum mechanics.
The second is superconducting circuits,
which is essentially
at the heart of the IBM
system we already heard about, where in
this implementation you
can picture a current
flowing in a loop one
way, or flowing in a loop
in another way representing
the zeroes and the ones.
Trapped ions is a very
interesting approach
where you essentially picture atoms with
different energy levels
and the lowest state can
represent a zero and the excited state can
represent a one, and
finally photons, which
is my own area of expertise,
where, for example,
the polarization of a photon
being polarized one way
versus polarized another
way can represent the
zeroes and ones, so these
are all viable systems
where around the world
there are a number of groups
working on these approaches
where we are developing
tools and technology to get
down to the quantum level
and to demonstrate these
quantum information protocols.
In our own department, the
five faculty I mentioned
just to go through them very quickly,
the first want to mention
is Jason Kessner, he's
a relatively new faculty
member, he joined the
department about six years
ago, he's a theorist,
primarily focusing on
spin qubits, but more
broadly on an area called quantum control,
so this is kind of related
to the idea of using feedback
and feed forward and
circuitry, if you will,
to implement quantum error correction and
control the errors in
these quantum systems.
The second group is
comprised of myself and
my colleague Jim Fransen,
we're working with
photon qubits, so single
photons or particles of
light to do these quantum operations, so
it's a remarkable system
to kind of calibrate
a single photon is a really
tiny thing, coming out
of these light bulbs are
something like 10 to the 25th
photons per second,
we're doing experiments
with one photon, so this
a completely crazy area
of physics with a lot of
interesting surprises,
and fun to work on.
The fourth faculty team
member I'll mention is
Sebastian Defner, this
is the newest addition
to our department, he
arrived in 2016 and has
already been doing all
kinds of wonderful things
in a generally broad area
called quantum thermodynamics.
So his research essentially
covers all of the qubit
approaches from the sense
of how much work is needed,
how much energy is consumed, what are the
speed limits, how fast can we
process these informations,
what is it really gonna
take to achieve quantum
supremacy, what are
the physical resources.
And, finally, I want to
mention Yuan Washi, he's
sorta the most senior
member in our department
in the sense that he's
been here since 1990, he's
one of the pioneering
research members of the
physics department and he's best known for
something called quantum
imaging, which is an area
using quantum information
processing techniques to
basically take better
pictures, higher resolution,
better microscopy, better
lithography, and so on,
so again, kind of a quantum
information advantage
over classical systems.
So, that's it, that's
just a very brief overview
of what we've got going on
in the physics department
and I hope that I left
you with the idea that
there's a lot of quantum
computing research
going on over there, we
have five faculty members
working in slightly
different areas, we're all
interrelated and collaborative,
we have PhD students,
undergraduates, and it's great
to introduce myself here,
it's great to collaborate,
and I look forward to
getting to know some of you
a lot better, thank you.
(applause)
