| 0:00:04 | this recording the companies the application of our pay a long range then you have |
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| 0:00:09 | tolerance entanglement distribution |
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| 0:00:11 | this is a theoretical protocol for creating a stream of entangled q bits between alice |
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| 0:00:17 | and bob well understood to be the remote from one another |
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| 0:00:22 | protocol assumes that there is a series or technology components corpora pita stations that span |
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| 0:00:28 | the gap between alice and bob |
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| 0:00:30 | we aim for a good scalability so that if the distance between alice and bob |
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| 0:00:35 | were increased we would need to scale the resources we you require only a little |
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| 0:00:42 | worse than linearly |
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| 0:00:44 | moreover where we attempt entanglements between two components whether they be within the repeat a |
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| 0:00:51 | station or between two successive repeated stations |
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| 0:00:54 | we assume we are much more likely to pay or and to succeed |
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| 0:00:58 | so he's how the protocol goes |
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| 0:01:00 | within each repeat a station we cook up some small scale entangled objects which are |
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| 0:01:05 | as depicted here these are prostate diagrams we each got is a cuban and each |
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| 0:01:10 | line represents an entanglement relationship there are two kinds of object to a tree across |
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| 0:01:15 | state and a snowflake crossed a |
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| 0:01:20 | these are proposed for two different things that really across states are aimed at creating |
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| 0:01:25 | entanglement between successive repeat stations |
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| 0:01:30 | so we look at a couple of trees into different feature stations and we aim |
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| 0:01:33 | using a long range entanglement channel to use the close together |
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| 0:01:39 | if we succeed we will then create an entity quote a dumbbell prostate |
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| 0:01:45 | if we if we fail then we will have consumed and destroyed a two trees |
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| 0:01:50 | and we simply must have not trees that we will create an adequate number of |
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| 0:01:54 | dumbbells |
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| 0:01:55 | then in the second step of our protocol we used together all these small scale |
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| 0:02:00 | entangled entities across the entire technology |
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| 0:02:04 | and in fact this can be done in one time step |
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| 0:02:06 | so the idea is that we schedule a ten set entanglement between the leaf nodes |
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| 0:02:10 | in different neighbouring small structures here we have for such a schedule to tense and |
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| 0:02:16 | you idea is that what dumbbells and snowflakes on a sufficiently large in the first |
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| 0:02:22 | place that there are enough that tense |
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| 0:02:24 | that and this one attend is likely to succeed |
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| 0:02:28 | but we can schedule or are tense to take place simultaneously because they are independent |
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| 0:02:33 | of one another |
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| 0:02:35 | and when we make this attend we assume what we expect to see that on |
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| 0:02:41 | the whole they'll be at least one successful bridge between every pair of these entities |
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| 0:02:47 | in this diagram that's exactly one successful such every but of course that could be |
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| 0:02:53 | more than one and that's fine it's also acceptable if in some cases we fails |
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| 0:02:58 | i'll try to connect to of these entities as long as the proportion is small |
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| 0:03:02 | now the next step is to tied it is and remove all the industry shook |
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| 0:03:05 | units even behind only the course of the snowflakes so that needs to much simpler |
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| 0:03:10 | structure like this |
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| 0:03:11 | and then zooming out we see that this is how we have achieved large scale |
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| 0:03:16 | entanglement but spanning the region always between alice and bob through a series of local |
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| 0:03:21 | cubic units entanglement |
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| 0:03:23 | and structure that we actually will be shooting for is a three dimensional |
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| 0:03:27 | topologically protected cluster state |
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| 0:03:30 | as started by |
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| 0:03:31 | a rubber rosen don't from coworkers to this insight here |
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| 0:03:34 | shows the pattern that we're going for |
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| 0:03:37 | however that will be somewhere regions and regions where we have not entangled humans and |
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| 0:03:41 | this is deliberate |
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| 0:03:43 | because by achieving by implementing to such a long running avoid its as in shown |
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| 0:03:48 | in this diagram |
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| 0:03:49 | when we then |
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| 0:03:50 | a measure out with single keep it measurements pool but you are a few bits |
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| 0:03:55 | in the entire technology |
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| 0:03:57 | the result will be two remaining regions one in the |
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| 0:04:02 | area of control and s and one in boats domain |
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| 0:04:06 | and these two regions well each represent |
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| 0:04:10 | a topologically encoded single keep it |
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| 0:04:14 | but moreover the too few bits will be ten with one another you nobel state |
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| 0:04:20 | so in this way we create robustly or entangled units without a simple and then |
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| 0:04:26 | he technologies available |
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| 0:04:27 | for |
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| 0:04:28 | acceptance cycle to create a second such |
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