this recording the companies the application of our pay a long range then you have
tolerance entanglement distribution
this is a theoretical protocol for creating a stream of entangled q bits between alice
and bob well understood to be the remote from one another
protocol assumes that there is a series or technology components corpora pita stations that span
the gap between alice and bob
we aim for a good scalability so that if the distance between alice and bob
were increased we would need to scale the resources we you require only a little
worse than linearly
moreover where we attempt entanglements between two components whether they be within the repeat a
station or between two successive repeated stations
we assume we are much more likely to pay or and to succeed
so he's how the protocol goes
within each repeat a station we cook up some small scale entangled objects which are
as depicted here these are prostate diagrams we each got is a cuban and each
line represents an entanglement relationship there are two kinds of object to a tree across
state and a snowflake crossed a
these are proposed for two different things that really across states are aimed at creating
entanglement between successive repeat stations
so we look at a couple of trees into different feature stations and we aim
using a long range entanglement channel to use the close together
if we succeed we will then create an entity quote a dumbbell prostate
if we if we fail then we will have consumed and destroyed a two trees
and we simply must have not trees that we will create an adequate number of
dumbbells
then in the second step of our protocol we used together all these small scale
entangled entities across the entire technology
and in fact this can be done in one time step
so the idea is that we schedule a ten set entanglement between the leaf nodes
in different neighbouring small structures here we have for such a schedule to tense and
you idea is that what dumbbells and snowflakes on a sufficiently large in the first
place that there are enough that tense
that and this one attend is likely to succeed
but we can schedule or are tense to take place simultaneously because they are independent
of one another
and when we make this attend we assume what we expect to see that on
the whole they'll be at least one successful bridge between every pair of these entities
in this diagram that's exactly one successful such every but of course that could be
more than one and that's fine it's also acceptable if in some cases we fails
i'll try to connect to of these entities as long as the proportion is small
now the next step is to tied it is and remove all the industry shook
units even behind only the course of the snowflakes so that needs to much simpler
structure like this
and then zooming out we see that this is how we have achieved large scale
entanglement but spanning the region always between alice and bob through a series of local
cubic units entanglement
and structure that we actually will be shooting for is a three dimensional
topologically protected cluster state
as started by
a rubber rosen don't from coworkers to this insight here
shows the pattern that we're going for
however that will be somewhere regions and regions where we have not entangled humans and
this is deliberate
because by achieving by implementing to such a long running avoid its as in shown
in this diagram
when we then
a measure out with single keep it measurements pool but you are a few bits
in the entire technology
the result will be two remaining regions one in the
area of control and s and one in boats domain
and these two regions well each represent
a topologically encoded single keep it
but moreover the too few bits will be ten with one another you nobel state
so in this way we create robustly or entangled units without a simple and then
he technologies available
for
acceptance cycle to create a second such