so this is Dave Schuster's lab behind
me you can see four dilution
refrigerators all operating that is
the noise that you hear is pulse tubes
operating to keep these fridges close to
zero degrees Kelvin specifically they're
close to about
millikelvin which keeps all of the
qubits that we have in the quantum regime.
so
let's go into here and I can show you
the experiment that I've been working on
now I'm taking out one of the chips that
I fabricated and each one of these chips
is technically one of the whole
experiments and I'll talk about what's
going on on each of these chips in a bit
but the way that we manufacture these
chips is using the nano fabrication
facility here at the University of
Chicago the metal that you're seeing on
here is niobium that's the silvery gray
material that comprises most of this
chip the gaps that you're seeing in
between pretty much allow us to form
each of the microwave elements that
you're seeing the niobium and aluminum
that we use for the qubit circuit both
have transition temperatures at 9 and 1
Kelvin respectively
and when I say transition temperatures I
mean the transition temperature at which
each of these metals goes from a normal
metal to a super conducting metal.  As in inputting
current into the material has no loss no
matter how far that current travels
So I actually have a device similar to this on the top
of this little cabinet here
and it
just pumps out some static
that current flows 
from this device to the top of any one
of those dilution refrigerators if you
put your experiment in there and that
current flows from the top at room
temperature down each stage of the
refrigerator where each stage is at a
lower and lower temperature and it makes
its way all the way down to one of the
lines on
those chips and then it makes its way
very close to the qubit and that
proximity of that current to the qubit
induces a magnetic field so it's it's
kind of a strange effect but we use
classical current on the outside of the
fridge to tune the transition energy of
these qubits on the inside of the fridge
and they're very close like the spacing
between this current of qubits on the
order of
four microns
that's how close these these
and that's like a
that's a classical source of current
outside
tuning the magnetic
that is an inherently very quantum
discreet object
which is still kind of nuts when you think about it
but in order to make that happen we put
each of these chips inside mounted IBM
board caps and mount those caps to
boards like this each of these cables
run out of several layers of shielding like
this and these SMA wires connect to here
and we place each of these boards on the
inside of these layers of shielding and
these wires connect to the base stage of
the refrigerator and when we put our
chips in here and connect these wires
out to these SMA cables into the fridge
this essentially allows us to interface
with our quantum experiments classically at room temperature out here
but then into the fridge at cryogenic temperatures at 20
millikelvin
but these guys are  mounted all
inside several layers of sheilding
so in this refrigerator we're downstairs now
from the main lab and we've taken apart
this adsorption refrigerator which gets
down to about 850 millikelvin which is
just past the transition temperature for
aluminum which means the qubits that we
put in here made of aluminium are just
past the point where they turn into kind
of well-behaved quantum qubits so when
they're placed in this refrigerator you
can actually use this to do pretty good
quick debugging for you know proposed
designs or proposed experiments so my
sample is actually in here right now and
you can see attached to the base plate
which is the coldest object in this
fridge there is a copper post coming
from the bottom carrying that cold base
plate temperature up to the IBM Board
where my chip is mounted inside and you
know wire bond and mounted
and essentially connected to these SMA
traces coming off of the board I have a
solenoid connected on the top here which
means the global magnetic field coming
from the solenoid talks to all of the
qubits on the surface of my chip so in
this case I have neglected to hook up
basically individual tuning lines to
each of my qubits instead choosing to
tune all of them at the same time with
one solenoid for debugging purposes the
rest of this is basically just filtering
microwave electronics to make sure that
the noise coming from our experimental
measure
apparatus and you know thermal effects from
higher temperature stages of the fridge
such as this top stage or this 100 millikelvin
stage do not actually influence the rest
of our experiment down here
one such circuit element is a circulator
which is based on the back here which is
a 3 port element if you put in power on
one end it comes out on the other end
and not the third end putting power in
on this end flows it out third port and
not on any of the other ports and the
third port close out the first port so
if you're putting in power here you can
put your measurement apparatus here then
the measurement signal comes out here
and your output is here and that
prevents noise coming in on the wrong
directions such as if noise came back on
the output line who would actually flow
to the input line and not to your sample
so devices like that can be used to kind
of help isolate and clean up microwave
signals that you use to kind of measure
what has happened with your qubits and
technologies like that plus the readout
resonator that we discussed before have
kind of increased the qubit lifetimes that we see from
you know the tens of nanoseconds to what
what we're seeing now which is the
hundreds of microseconds and you know who knows where we'll go next
