0 00:00:02,220 --> 00:00:02,850 Piotr Chrusciel: Okay, good. 1 00:00:04,110 --> 00:00:07,319 Jorge Pullin: Good so crucial will speak about gravitational wave guys the other. 2 00:00:08,069 --> 00:00:09,300 Piotr Chrusciel: Okay, good so. 3 00:00:11,250 --> 00:00:18,660 Piotr Chrusciel: Good morning, or afternoon everyone good afternoon if you're in jenna but then morning to some of you. 4 00:00:20,250 --> 00:00:36,630 Piotr Chrusciel: When I was invited to give the start I gave it a bit of thought, because I thought that if people hear that i'm giving experimental talks in a quantum gravity me not my reputation, with growing so. 5 00:00:37,740 --> 00:00:46,830 Piotr Chrusciel: So I was a bit worried and we are we're both invited to give this talk with Bobby and I think he saw that night. 6 00:00:47,880 --> 00:00:49,410 Piotr Chrusciel: Anyway, so. 7 00:00:50,610 --> 00:00:55,470 Piotr Chrusciel: Since i'm here at tech you're about to tell you about some gravity wave wave guide. 8 00:00:56,610 --> 00:00:58,980 Piotr Chrusciel: This is work done, we seen something. 9 00:00:58,980 --> 00:01:12,870 Piotr Chrusciel: called the research platform for testing and the quantum and gravity interface at the Faculty Vienna and the slides i'm using here are all a lot of the voter and tonight's meeting. 10 00:01:14,070 --> 00:01:27,390 Piotr Chrusciel: So what is this testing the serious business mean right, so this is testing quantum gravity interface, by the way, can you see my laser pointer please. 11 00:01:28,410 --> 00:01:28,770 Jorge Pullin: Yes. 12 00:01:29,190 --> 00:01:29,580 Okay. 13 00:01:30,750 --> 00:01:45,960 Piotr Chrusciel: This is called a Vienna university research platform, which means that we get some extra money from director to do what we're doing this involves several groups, so a group of 50, which is an expert in untangle photons. 14 00:01:47,190 --> 00:01:51,690 Piotr Chrusciel: group of markets aren't which studies matter waves group of. 15 00:01:52,860 --> 00:02:03,840 Piotr Chrusciel: mark, which has been my nano mechanical devices group of brookner who looks at causal structures and quantum physics and we even have a colleague from the Faculty of astronomy. 16 00:02:05,190 --> 00:02:21,360 Piotr Chrusciel: And the big open question is, how does gravity act on quantum systems that's, the question we wanted to address as a consortium of all these teams and the sub question i'm going to talk about today's how. 17 00:02:22,800 --> 00:02:36,360 Piotr Chrusciel: Well, a little provocatively How does it feel time and also how do entangle photons time so well let's be more precise, or less. 18 00:02:38,400 --> 00:02:44,460 Piotr Chrusciel: romantic How does grove it it masters quantum systems, including a quantum entanglement. 19 00:02:45,480 --> 00:02:47,460 Piotr Chrusciel: So the question is. 20 00:02:48,630 --> 00:03:05,520 Piotr Chrusciel: Especially, how do we test this we have tested this and, of course, we have a test of classical physics in newtonian gravity that's something to do we have a lot of tests of classical physics interacting with general activities are the hottest of Dr we have some test. 21 00:03:06,540 --> 00:03:06,840 This. 22 00:03:07,890 --> 00:03:17,730 Piotr Chrusciel: Some experiments testing quantum mechanics in newtonian gravity and i'm going to mention them shortly and the point that we. 23 00:03:18,360 --> 00:03:28,500 Piotr Chrusciel: wanted to make and the claim is that none of the experiments which have been performed to TAO today show unique signatures of general relativity and quantum mechanics. 24 00:03:28,830 --> 00:03:33,990 Piotr Chrusciel: In a single experiment, so, in other words, I experienced quantum mechanics and Newton and gravity. 25 00:03:34,380 --> 00:03:51,480 Piotr Chrusciel: Now experiments in general relativity and classical physics, but there are no experiments which do something which is specifically general relativity and specifically quantum mechanics and our proposal is that maybe photonic quantum systems or the right way to. 26 00:03:53,130 --> 00:03:53,580 Piotr Chrusciel: test. 27 00:03:55,110 --> 00:03:56,430 Piotr Chrusciel: Our theory yeah. 28 00:03:57,690 --> 00:04:10,890 Piotr Chrusciel: So let me this is about time and quantum mechanics and generativity so let me brand very quickly about the some classical test of general relativity and i'm going to go. 29 00:04:11,640 --> 00:04:28,260 Piotr Chrusciel: All of them, but one which is gravitational redshift which is going to be relevant to the experiments in time talking about started or predicted already by Einstein in 1907 well before generativity using the equivalence principle. 30 00:04:29,550 --> 00:04:44,040 Piotr Chrusciel: first test in 24 by eddington who suggested that it could be tested by looking at spectral lines of light doors and so started in 25 and culminating in 2005. 31 00:04:46,050 --> 00:04:51,630 Piotr Chrusciel: They found red guy experiment I don't think I need to explain what it is to anyone in this audience. 32 00:04:52,800 --> 00:05:05,580 Piotr Chrusciel: Half allocating they put a clock on an airplane and tested both the special relativistic time dilation and the general relativistic. 33 00:05:06,840 --> 00:05:12,750 Piotr Chrusciel: Time snowing or all time accelerating whatever you call this the accuracy of 10%. 34 00:05:14,580 --> 00:05:19,620 Piotr Chrusciel: Improved in 76 using rocket flies by vessel and friends to. 35 00:05:20,730 --> 00:05:24,990 Piotr Chrusciel: accuracy of one party in about 10 to minus four. 36 00:05:26,370 --> 00:05:31,230 Piotr Chrusciel: And the best test of the gravitational redshift that we have so far is a. 37 00:05:32,280 --> 00:05:49,020 Piotr Chrusciel: Success of failure, the failure was the launch of the GPS satellite European GPS satellites Teresa in Atlanta in 2014 the launch didn't work quite as it was planned and instead of. 38 00:05:50,730 --> 00:05:53,130 Piotr Chrusciel: The spot satellites would have gone to Nice. 39 00:05:54,330 --> 00:06:01,230 Piotr Chrusciel: spherical beach instead they went to a particular ones, and that was a blessing for us, because then. 40 00:06:02,430 --> 00:06:14,520 Piotr Chrusciel: The satellites are evolved being in a very in gravitational field, because of the electricity of the orbits rather than on a circle, and so you can then. 41 00:06:15,840 --> 00:06:20,730 Piotr Chrusciel: Do experiments will test the redshift all the time. 42 00:06:21,840 --> 00:06:25,740 Piotr Chrusciel: Local time versus Eric celestial time. 43 00:06:27,330 --> 00:06:42,720 Piotr Chrusciel: versus less time on onboard the satellite, these are the results published by this group in 2018, so this is a blue points of the data points the yellow is the GR prediction. 44 00:06:43,800 --> 00:06:55,290 Piotr Chrusciel: The residuals are here, if you look at the residuals the three orders of orders of magnitude smaller than than the signal itself, and this gives a. 45 00:06:56,310 --> 00:06:57,000 Piotr Chrusciel: test of. 46 00:06:58,110 --> 00:07:07,620 Piotr Chrusciel: gravitational redshift at accuracy in one part in in tend to minus two five, so the best results so far. 47 00:07:09,990 --> 00:07:20,820 Piotr Chrusciel: When talking about classical best of general relativity Let me mention this one, which is often mentioned because it's mentioned as the record holder of. 48 00:07:22,380 --> 00:07:24,120 Piotr Chrusciel: distance between the clocks. 49 00:07:25,200 --> 00:07:45,750 Piotr Chrusciel: Namely 30 centimeters the previous ones, obviously involved a large large distances so here in this experiment reported in 2010 two and France, said that they moved two clocks by 30 centimeters and they were able to measure the difference of time of. 50 00:07:46,830 --> 00:07:48,840 Piotr Chrusciel: The rate of flow of time and decides. 51 00:07:49,890 --> 00:08:03,930 Piotr Chrusciel: That personally when I look at this data, here I So these are the data right the blue lines, the blue points are coming from the lower clock and the red points are coming from the upper clock. 52 00:08:05,490 --> 00:08:12,270 Piotr Chrusciel: Well, if you look at their bond the red points and remove a couple of points here and I. 53 00:08:13,410 --> 00:08:19,620 Piotr Chrusciel: My feeling is that the straight line is actually a very good teacher to to these data points so, in other words. 54 00:08:20,730 --> 00:08:38,130 Piotr Chrusciel: Obviously, we think that there should be an effect and i'm not completely convinced that they really demonstrated it with this displacement of 30 centimeters, so I think that lab scale displacements or still an open game in this business. 55 00:08:39,420 --> 00:09:00,960 Piotr Chrusciel: Now let me mention another effect, whether the redshift with the Scottish up your effect and, as far as i'm concerned it's hard to say whether these are different effects or not I mean calculation for me is the same you're just looking at curves in space time and compare the. 56 00:09:02,460 --> 00:09:15,030 Piotr Chrusciel: Time house of time flows along these things never there is this another name for this, this is called track your effect the experiment is it you sitting on us, you sending raider into. 57 00:09:17,670 --> 00:09:20,550 Piotr Chrusciel: The planet in this case Venus and. 58 00:09:22,230 --> 00:09:32,550 Piotr Chrusciel: A strong raider game with reflected comes back and you measure the time it takes to go back and forth, and you compare this to the time. 59 00:09:33,180 --> 00:09:50,670 Piotr Chrusciel: That it would have taken to if space time was binkowski between these things so so you get a prediction accuracy with up to 10% with gen activity, the one should say that there was a bit of a discussion. 60 00:09:51,870 --> 00:10:05,760 Piotr Chrusciel: How they experiment was biased by light traveling through near the sun in the region, where there is a corona this plasma there is all kinds of stuff How does this affect. 61 00:10:06,570 --> 00:10:14,280 Piotr Chrusciel: The results and so forth, in case, one gets something which looks very much like generativity up to 10% and. 62 00:10:15,150 --> 00:10:33,690 Piotr Chrusciel: By now, we can do much better because one can repeat this experiment not sending light from us to Venus but sending light to both first the weekend about probe and, finally, the finest experiments seems to be like sent to communication with the Cassini. 63 00:10:39,000 --> 00:10:51,960 Piotr Chrusciel: spacecraft where the accuracy of one party 10 to five was achieved for the shapira effective similar to the accuracy, you get for the rich lift weights, with the GPS satellites. 64 00:10:53,220 --> 00:11:09,420 Piotr Chrusciel: Now I, the reason I listed all these things, was to make it clear that this is all classical music and classical flight flying back and forth, and we trying to measure properties of classical light now, what about one from physics. 65 00:11:10,440 --> 00:11:20,850 Piotr Chrusciel: Well, the first quantum test of eternal gravity is the famous cow experiment cow being colella over hauser and burner. 66 00:11:21,810 --> 00:11:42,090 Piotr Chrusciel: published in 75 and the idea is to the following you set up a neutron interferon and you send neutrons in a machine which deflects them, so you create a beam splitter and then you look at another it's another. 67 00:11:43,350 --> 00:11:45,960 Piotr Chrusciel: place where the beams are really. 68 00:11:48,180 --> 00:12:04,650 Piotr Chrusciel: Well reconnected redirected together, and you have Newton detectors behind this and you count how many nutrients get in there, and how does gravity enter here well you rotate this machine. 69 00:12:05,940 --> 00:12:23,610 Piotr Chrusciel: along its axis, and this is constructed in a way, then when it rotated then one of the beams will be higher than the other one, so, in other words, you can put your machine, so that they both beams out of the same height and then you can rotate it and one of the beams goes higher. 70 00:12:24,720 --> 00:12:34,260 Piotr Chrusciel: Well, you just take your favorite shredding equation throw in a newtonian potential constant potential in the gravitational field. 71 00:12:35,430 --> 00:12:42,930 Piotr Chrusciel: You get can calculate what you should see after this experiment and you get a very good experiment. 72 00:12:43,350 --> 00:12:58,290 Piotr Chrusciel: Agreement with the schrodinger equation, with the newtonian potential right, so no general relativity here, even though one could make the point that, of course, one interpretation possible is that when these guys travel different heights. 73 00:12:59,310 --> 00:12:59,880 Piotr Chrusciel: Time. 74 00:13:01,440 --> 00:13:15,390 Piotr Chrusciel: flows differently on the lower arm and the upper one, and this is the dinner a statistic explanation of the difference of the time of arrival and therefore the difference of faith shifts. 75 00:13:15,900 --> 00:13:28,770 Piotr Chrusciel: And Well, yes, you can make an argument like that, but then it makes sense to invoke outcomes rather and say, well, if you don't need to enroll activity but Newton gravity's nothing. 76 00:13:30,210 --> 00:13:33,810 Piotr Chrusciel: don't come, saying that this is a test of generated. 77 00:13:35,160 --> 00:13:39,480 Piotr Chrusciel: So this is certainly a beautiful experiment, but it's not a test internal activity. 78 00:13:41,100 --> 00:13:45,840 Piotr Chrusciel: Another experiment in the same spirit, about 2000. 79 00:13:47,070 --> 00:13:52,440 Piotr Chrusciel: Well, in the same spirit in that you're using quantum mechanical system. 80 00:13:53,550 --> 00:13:59,790 Piotr Chrusciel: and evolving in a gravitational field, so you have something which is called a. 81 00:14:02,850 --> 00:14:12,270 Piotr Chrusciel: cesium items fountain which sends items up the items on Monday plated using laser beams in a very sophisticated way. 82 00:14:13,500 --> 00:14:15,870 Piotr Chrusciel: You put your experiment in the neutron. 83 00:14:16,980 --> 00:14:22,500 Piotr Chrusciel: In the shooting equation is a nutrient potential you get very good. 84 00:14:26,580 --> 00:14:30,510 Piotr Chrusciel: Well agreement with the theory again. 85 00:14:32,220 --> 00:14:36,600 Piotr Chrusciel: People have put forward interpretation that has to do with a. 86 00:14:37,890 --> 00:14:51,270 Piotr Chrusciel: Different flow of time at different heights well, I think that this is a bit exaggerated for this experiment, if you can explain it with treating the equation. 87 00:14:53,010 --> 00:14:53,430 Piotr Chrusciel: Let me. 88 00:14:53,520 --> 00:14:54,630 Abhay Vasant Ashtekar: mention one last. 89 00:14:54,630 --> 00:15:02,730 Abhay Vasant Ashtekar: auriemma justice so one could even be more precise right, because by example in the experiment with the neutron. 90 00:15:03,510 --> 00:15:04,410 Abhay Vasant Ashtekar: could actually. 91 00:15:04,980 --> 00:15:10,920 Abhay Vasant Ashtekar: Say that well I could calculate and analyze it just using the direct equation in the. 92 00:15:11,280 --> 00:15:11,520 Piotr Chrusciel: In this. 93 00:15:11,760 --> 00:15:23,640 Abhay Vasant Ashtekar: Space time and just showing you the question and see that the effect is much the change in using shorter equation, what is the equation of course space, time is. 94 00:15:24,720 --> 00:15:29,940 Abhay Vasant Ashtekar: Is of certain order of magnitude, which is way beyond the position of this experiment. 95 00:15:30,390 --> 00:15:30,870 Abhay Vasant Ashtekar: And okay. 96 00:15:30,900 --> 00:15:31,650 Piotr Chrusciel: So, so I. 97 00:15:32,520 --> 00:15:37,350 Piotr Chrusciel: Never have this calculation, so can you send me very fancy so if there's a calculation. 98 00:15:38,760 --> 00:15:39,480 Piotr Chrusciel: calculation. 99 00:15:39,750 --> 00:15:42,660 Abhay Vasant Ashtekar: With the experiment came I did it myself, but I had. 100 00:15:42,660 --> 00:15:43,290 Piotr Chrusciel: Oh okay. 101 00:15:43,500 --> 00:15:46,170 Abhay Vasant Ashtekar: Do you do do it again, but it's not difficult, I mean one. 102 00:15:46,200 --> 00:15:50,280 Piotr Chrusciel: Okay, good expired, so in that case, one doesn't do it in walk outcomes. 103 00:15:50,340 --> 00:15:55,500 Abhay Vasant Ashtekar: Is that one can just say well it's not because of this equidistant experiment doesn't see the distinction between the two. 104 00:15:57,000 --> 00:16:03,210 Piotr Chrusciel: Right, I mean so yeah so so yeah Of course there is a question of accuracy, because presumably good. 105 00:16:04,800 --> 00:16:06,690 Piotr Chrusciel: accuracy high enough, you could. 106 00:16:06,840 --> 00:16:10,920 Abhay Vasant Ashtekar: Start some right exactly but, but the one does not try. 107 00:16:11,490 --> 00:16:15,630 Piotr Chrusciel: This one doesn't do this, and this one doesn't do either and. 108 00:16:17,460 --> 00:16:20,070 Piotr Chrusciel: Let me mention one last experiment which. 109 00:16:22,530 --> 00:16:37,740 Piotr Chrusciel: is not directly related to to this flow of time business but still a beautiful experiment which involves neutrons so quantum objects in a gravitational field so in Vienna we like to call these experiments. 110 00:16:39,030 --> 00:16:47,640 Piotr Chrusciel: Experiments because that's a colleague here, so he was a collaborator on on this paper which first offer, and this is key. 111 00:16:48,870 --> 00:17:02,850 Piotr Chrusciel: And he's been involved in this experiment and several other along the same line, and so what what is the experiment about well you send neutrons between two. 112 00:17:05,160 --> 00:17:05,730 Piotr Chrusciel: plates. 113 00:17:06,960 --> 00:17:22,080 Piotr Chrusciel: So so and these plates is one above the other and therefore you have in your gravitational potential between these two plates, so thank well wait a minute i've done a. 114 00:17:22,920 --> 00:17:31,560 Piotr Chrusciel: quantum mechanics point one, so I have to infinity potential walls and the linear potential between the walls, I can solve this problem for. 115 00:17:31,890 --> 00:17:41,730 Piotr Chrusciel: eigenvalues and, indeed, you can do it and it's one of the elementary but one of the cases where you can get explicit solutions. 116 00:17:42,270 --> 00:17:51,630 Piotr Chrusciel: And now the problem in so far every functions are explicit actions, but so we get a spectrum for this problem with every functions which have. 117 00:17:52,590 --> 00:18:09,930 Piotr Chrusciel: Safe you're going height and the potential is varying linearly and that's the energy levels, you can get and indeed in this paper they reported that they get they can see this energy that also the output of this experiment this paper goes back to 2002. 118 00:18:11,490 --> 00:18:21,030 Piotr Chrusciel: very interesting variation of this experiment in 2015 where you still have your. 119 00:18:22,320 --> 00:18:22,650 Piotr Chrusciel: To. 120 00:18:24,390 --> 00:18:30,390 Piotr Chrusciel: sell so you still send the your your your neutron beams between two plates, but then. 121 00:18:31,560 --> 00:18:35,160 Piotr Chrusciel: You let the beam run above. 122 00:18:36,300 --> 00:18:41,580 Piotr Chrusciel: vibrating plate, so this red thing is vibrating now because this thing is vibrating. 123 00:18:42,420 --> 00:18:52,230 Piotr Chrusciel: It induces transitions between the energy levels in the way you know, maybe not from quantum mechanics one one but one or two to one or something like that. 124 00:18:52,830 --> 00:19:04,110 Piotr Chrusciel: So you use the standard transition rules that you get from a standard quantum mechanics in a perturbation skin and you can measure again agreement with. 125 00:19:05,430 --> 00:19:09,300 Piotr Chrusciel: With this of what you see at the end with with the theory. 126 00:19:10,620 --> 00:19:18,840 Piotr Chrusciel: Again shredding equation with between your potential beautiful experiment very difficult very precise yes. 127 00:19:19,500 --> 00:19:22,500 Carlo Rovelli: Yes, did you do medical issue, I think I think we have time this is. 128 00:19:24,000 --> 00:19:30,510 Carlo Rovelli: Of course I this is going to say I agree with everything you said, but you, you talk about the outcome, racism and then. 129 00:19:31,920 --> 00:19:35,640 Carlo Rovelli: See, if you agree with this, which is slightly different take on what you say. 130 00:19:36,780 --> 00:19:49,350 Carlo Rovelli: If the question is to test general relativity Of course these things don't test generativity I percent with you that same effect is obtained the segment infinity limit Tony Tony. 131 00:19:50,460 --> 00:19:54,060 Carlo Rovelli: But if the question is how to better think about this, what goes on. 132 00:19:55,170 --> 00:20:00,990 Carlo Rovelli: I mean generative it has a lot of independent support from from elsewhere so. 133 00:20:02,310 --> 00:20:13,470 Carlo Rovelli: When I observe a phenomenon earth I don't say I don't need Copernicus I I don't need you to ptolemy is good enough, so I think telling Mike because of our can razor. 134 00:20:14,340 --> 00:20:28,260 Carlo Rovelli: I say that my best understanding of the world, so far is with Newton was that autonomy, so I think that this way, so I, I would say that maybe i'm too much of a relativist but. 135 00:20:29,520 --> 00:20:40,380 Carlo Rovelli: classical genetic which is sufficient to confirm from elsewhere, then I prefer to seek at say they is interference effectively sets in terms of different time. 136 00:20:41,070 --> 00:20:54,390 Carlo Rovelli: of flight rather than on a sort of peculiar limit, which is newtonian potential that's not in contradiction with what you say, but it uses the outcome, based on the different manner. 137 00:20:56,580 --> 00:20:57,510 Carlo Rovelli: Would you disagree with that. 138 00:20:59,040 --> 00:21:08,310 Piotr Chrusciel: So i'm not sure if I understood correctly, but what you're saying is that all this is compatible with Dr right So in this sense it tests your. 139 00:21:09,690 --> 00:21:12,960 Piotr Chrusciel: But what i'm saying is you don't need your for that. 140 00:21:13,650 --> 00:21:21,420 Piotr Chrusciel: yeah so we know that the weekly meeting Dr is Newton theory so we're happy with this right we don't know what the. 141 00:21:22,440 --> 00:21:29,790 Piotr Chrusciel: Week limit of quantum gravity is because we don't know what quantum gravity is that this has nothing to do is quantum gravity i'm talking about. 142 00:21:30,390 --> 00:21:34,140 Carlo Rovelli: To go into gravity gravity sure acting with quantum systems. 143 00:21:34,470 --> 00:21:39,600 Piotr Chrusciel: And these experiments show that is a question which makes sense and it works so. 144 00:21:40,680 --> 00:21:59,430 Piotr Chrusciel: At the newtonian level certainly does and therefore presumably at the general district level and what i'm saying that we haven't checked now no experiments which go beyond the newtonian regime here and the point is to propose one and that's what i'm going to. 145 00:22:00,720 --> 00:22:05,610 Piotr Chrusciel: To do you know what follows that, then I don't know if if that's. 146 00:22:06,630 --> 00:22:07,860 Piotr Chrusciel: What you had in mind here but. 147 00:22:11,280 --> 00:22:13,740 Carlo Rovelli: Well, maybe this is a longer discussion so. 148 00:22:13,950 --> 00:22:16,290 Carlo Rovelli: yeah let's let it open I don't think we. 149 00:22:17,190 --> 00:22:18,240 Carlo Rovelli: disagree, but I. 150 00:22:20,040 --> 00:22:20,250 Piotr Chrusciel: don't. 151 00:22:20,940 --> 00:22:21,930 Piotr Chrusciel: yeah yeah okay. 152 00:22:23,700 --> 00:22:24,060 Piotr Chrusciel: Good. 153 00:22:25,380 --> 00:22:28,710 Piotr Chrusciel: So yeah so, then the point is okay so let's. 154 00:22:30,480 --> 00:22:48,780 Piotr Chrusciel: Take as a quantum system photons and protons single photons entangled photons assembly quantum object and there's no newtonian model for them, so we need a equations like maxwell's equations inequalities time we suddenly goes beyond Newton theory and that's. 155 00:22:49,920 --> 00:22:57,930 Piotr Chrusciel: Our point here that, if we do this, and then, of course, the question is protein sufficient. 156 00:23:00,390 --> 00:23:02,520 Piotr Chrusciel: accuracy in the experiments to get to a. 157 00:23:03,600 --> 00:23:09,750 Piotr Chrusciel: Certainly general relativistic regime, because you can still argue that when when we see in such a week field that. 158 00:23:11,250 --> 00:23:25,140 Piotr Chrusciel: One is testing a theory which is essentially a metric metric interaction of light and the metric is whatever it is doesn't have to be generativity could be many other metrics so. 159 00:23:25,770 --> 00:23:37,620 Piotr Chrusciel: When would need really to go the very precise experiments to be able to discern generativity rather models and that's going to be and I hope the future of this field better. 160 00:23:39,000 --> 00:23:50,280 Piotr Chrusciel: So so let's see so we talking about photonic quantum interferometry, and this is to be supposed to be a my colleagues like to think of it as the quantum version of the shapira effect. 161 00:23:51,720 --> 00:24:09,030 Piotr Chrusciel: Since this involves redshift you can think of this as a quantum version of the gravitational redshift effect, and I say what he said I don't really see a big difference between calling this Shapiro or gravitational redshift or anything like that I just do this as. 162 00:24:10,050 --> 00:24:19,980 Piotr Chrusciel: a test of quantum field theory interface time quantum field theory of a photon you know catch this time at this level, because space time not being very good. 163 00:24:20,490 --> 00:24:34,920 Piotr Chrusciel: But still being a bit cost, so this is a paper published about five years ago, which proposes an experiment involving photons, which is supposed to test. 164 00:24:36,330 --> 00:24:41,460 Piotr Chrusciel: The maximal equation because metric quantifies Max equation because metric. 165 00:24:42,930 --> 00:24:49,740 Piotr Chrusciel: With several hotels that's one of these that's my first paper on an experimental. 166 00:24:51,060 --> 00:25:01,680 Piotr Chrusciel: topic so my understanding is that if you look at the list of the authors and the last ones are those that did nothing there and. 167 00:25:02,460 --> 00:25:17,190 Piotr Chrusciel: The first person is the one who really did something here so feel the vita who is probably the driving force behind all this was kind enough not to put me in the last place of faith. 168 00:25:18,210 --> 00:25:29,430 Piotr Chrusciel: In any case, I was involved in this experiment in the designing of this experiment and, what is this supposed to do well, you send laser light. 169 00:25:30,270 --> 00:25:41,430 Piotr Chrusciel: into something which is called him mark tender interferometer that's the main for this kind of devices, and so the idea is you split your beam into two and. 170 00:25:42,090 --> 00:25:57,720 Piotr Chrusciel: something happens, meanwhile, and then you recombine the teams and you see what happened at the end, so this neutron CW experiment it's actually a mass enter experiment with with neutrons interferometer is neutrons. 171 00:25:58,770 --> 00:26:12,210 Piotr Chrusciel: So yeah when you, the point is that this arm of this interferometer is lower than this one, and therefore the photons traveling here travel. 172 00:26:13,290 --> 00:26:21,750 Piotr Chrusciel: Whether traveling in the higher arm traveling in a different potential than the photons traveling in the lower and therefore. 173 00:26:23,760 --> 00:26:35,040 Piotr Chrusciel: Since you know that there is gravitation redshift tilting the frequency will be shifted or you know that there is such a pure delay, so therefore the time will flow differently any case, no matter how you. 174 00:26:35,580 --> 00:26:47,310 Piotr Chrusciel: What names you put on it at the end, there should be a phase shift when these teams recombine here, and then you can certainly calculate this and that's the formula. 175 00:26:49,140 --> 00:26:51,030 Piotr Chrusciel: So what. 176 00:26:52,800 --> 00:26:58,890 Piotr Chrusciel: In order to understand the setup and to think of whether it makes sense let's look at some numbers here. 177 00:27:00,060 --> 00:27:00,990 Piotr Chrusciel: So when you. 178 00:27:02,790 --> 00:27:17,880 Piotr Chrusciel: calculate you can calculate the change of the waves vector in this system, it is something called the way vector and whatever the formula is just ignore it, for the moment, what is important is this number here, then there is a change of a wave vector which is. 179 00:27:19,230 --> 00:27:21,060 Piotr Chrusciel: About of this order. 180 00:27:22,500 --> 00:27:26,220 Piotr Chrusciel: In this experiment and, if you want to. 181 00:27:27,330 --> 00:27:38,820 Piotr Chrusciel: get a phase shift out of this phase shift is rough it is actually not quite the right equation, but at the simplest equation would be just change of the way vector times the length of the. 182 00:27:41,040 --> 00:27:42,150 Piotr Chrusciel: arm yeah. 183 00:27:43,320 --> 00:28:00,000 Piotr Chrusciel: Well, if you take this difference of fight between the arms to be of the order of one meter and you want to have a face shift with this order tend to minus four ads which my colleagues here in Vienna claim they can measure. 184 00:28:01,080 --> 00:28:10,110 Piotr Chrusciel: Well, they claim actually they can measure tend to minus five so tend to minus four is what you need to get a decent. 185 00:28:11,370 --> 00:28:25,260 Piotr Chrusciel: signal to noise ratio, well then, you need hundred nanometers Okay, so if this is hundred kilometers, and this is one meter, then you should get something which. 186 00:28:26,400 --> 00:28:29,310 Piotr Chrusciel: can be detected with the present technology. 187 00:28:31,050 --> 00:28:32,490 Piotr Chrusciel: In quantum optics. 188 00:28:33,630 --> 00:28:47,820 Piotr Chrusciel: Well, how do you get 100 kilometers yeah you could say well why don't you ask the late Lego guys to move the second arm not orthogonal II, but a meter higher than the first arm and then. 189 00:28:48,840 --> 00:28:53,010 Piotr Chrusciel: Going 30 times they can force is actually what we need so. 190 00:28:54,300 --> 00:29:01,350 Piotr Chrusciel: But I don't think they want to do that, so the idea is well why don't we put here a wave right. 191 00:29:02,670 --> 00:29:17,520 Piotr Chrusciel: So you put a wave guide between this murals and you can have hundred kilometers on your desk because can just call you wave guide and hundred kilometers will read. 192 00:29:18,510 --> 00:29:25,560 Piotr Chrusciel: It technically they say it's 20 the decibel loss, which means that, after hundred kilometers if you send in hundred. 193 00:29:26,160 --> 00:29:37,410 Piotr Chrusciel: photons here you're going to get one adult put right so 1% transmission rate 99% losses and that's something that they can live with right so. 194 00:29:38,130 --> 00:29:50,580 Piotr Chrusciel: They can send in enough photons here so that to get this detection at one person transmission rate hundred kilometres two weeks and hundred kilometres. 195 00:29:51,780 --> 00:29:53,940 Piotr Chrusciel: Which one meter he, of course, if you. 196 00:29:54,990 --> 00:29:57,270 Piotr Chrusciel: put this arm on. 197 00:29:58,380 --> 00:30:03,930 Piotr Chrusciel: Top of a very high tower on a satellite, then this changes the numbers. 198 00:30:05,220 --> 00:30:06,630 Piotr Chrusciel: helps you quite a bit, but. 199 00:30:07,890 --> 00:30:11,370 Piotr Chrusciel: let's talk about tabletop experiments now so just put two. 200 00:30:12,990 --> 00:30:14,040 Piotr Chrusciel: To wait guides here. 201 00:30:15,150 --> 00:30:16,650 Piotr Chrusciel: and try. 202 00:30:19,200 --> 00:30:19,860 Piotr Chrusciel: To do it. 203 00:30:21,240 --> 00:30:21,420 Abhay Vasant Ashtekar: But. 204 00:30:21,720 --> 00:30:23,370 Piotr Chrusciel: He I saw one yes. 205 00:30:24,180 --> 00:30:25,650 Abhay Vasant Ashtekar: For like Oh, I mean the thing is that. 206 00:30:26,880 --> 00:30:40,650 Abhay Vasant Ashtekar: You don't have to do things on the top of each other, because we can just I mean the the tube is much more than a meter so you could just have one one beam at the top of the tube are towards the top tube and one at the. 207 00:30:40,680 --> 00:30:49,230 Piotr Chrusciel: Bottom put another been there right but I I, I think that if I told the guys to do this, maybe just they probably yeah. 208 00:30:49,410 --> 00:30:49,980 Abhay Vasant Ashtekar: there's a be. 209 00:30:51,990 --> 00:30:53,400 Piotr Chrusciel: Okay, to have. 210 00:30:54,660 --> 00:30:55,950 Piotr Chrusciel: it's a what. 211 00:30:57,510 --> 00:31:11,790 Piotr Chrusciel: A beta of a disruption of their experimental setup but yes, in principle, why not right, I mean if you could do this if you're in vacuum, if you that would solve a lot of problems here. 212 00:31:12,900 --> 00:31:28,350 Abhay Vasant Ashtekar: Right so it's just it will not be I mean it'll just be it will be just a laser beam and not expecting another Armani can attack that's right, I mean you're saying that well one particular are put them talk to each other. 213 00:31:28,710 --> 00:31:31,710 Piotr Chrusciel: Well, you still need you still need two things to compare right. 214 00:31:31,740 --> 00:31:33,720 Piotr Chrusciel: Because otherwise what what, how do you know. 215 00:31:36,090 --> 00:31:37,950 Piotr Chrusciel: Right, so you need to answer so. 216 00:31:38,760 --> 00:31:40,560 Piotr Chrusciel: yeah different heights right. 217 00:31:40,590 --> 00:31:42,270 Abhay Vasant Ashtekar: So in the in the same arm. 218 00:31:42,930 --> 00:31:44,430 Piotr Chrusciel: yeah good to be emceeing. 219 00:31:44,610 --> 00:31:57,480 Abhay Vasant Ashtekar: today's right exactly and that that's what you would compare and so it could be just the two lasers, is what is needed it's not that to do different vacuum tubes that are needed for collaborative but Okay, please go. 220 00:31:59,280 --> 00:32:08,280 Piotr Chrusciel: Right okay so good so so, but our idea is to do it on a tabletop anyway, and so this is a version with actually three arms. 221 00:32:09,660 --> 00:32:21,180 Piotr Chrusciel: So you see that one wave guide is sitting lower than the second sitting lower than desert and a here the point of having three arms is the following. 222 00:32:22,200 --> 00:32:33,870 Piotr Chrusciel: We put an optical switch here which periodically, which is the beam from this arm to that arm so half of the beam always goes to the lower on. 223 00:32:34,350 --> 00:32:45,150 Piotr Chrusciel: And the optical switch makes a periodic switch between these two arms, so what is the gain of doing this well you get a periodic signal and periodic signals. 224 00:32:46,200 --> 00:32:56,790 Piotr Chrusciel: Are can be filtered out from noise so that's the idea of the three on configuration indeed there is quite a bit of Nice here. 225 00:32:57,300 --> 00:33:06,420 Piotr Chrusciel: fiber terminal systematic errors seesmic nice acoustic noise laser noise a dispersion nonlinear effect and so forth, you name it and. 226 00:33:07,110 --> 00:33:22,770 Piotr Chrusciel: If you have a colleague in quantum optics probably add several other things here so to get this kind of accuracy tend to minus five radiance which you think in terms of face is not much and. 227 00:33:24,480 --> 00:33:27,240 Piotr Chrusciel: let's think of two pi together. 228 00:33:28,800 --> 00:33:36,690 Piotr Chrusciel: or apply to you need to buy to get a full destructive interference between to be inside So here we talking about 10 minus five radiance. 229 00:33:37,980 --> 00:33:39,480 Piotr Chrusciel: which corresponds to a. 230 00:33:40,560 --> 00:33:42,390 Piotr Chrusciel: standardization of frequency. 231 00:33:43,500 --> 00:33:47,130 Piotr Chrusciel: Of this order, then this is a bit of a. 232 00:33:48,960 --> 00:33:53,700 Piotr Chrusciel: challenge but well the claim is that this can be done. 233 00:33:54,720 --> 00:33:55,260 Piotr Chrusciel: So. 234 00:33:57,180 --> 00:34:10,500 Piotr Chrusciel: Let me tell you a little more about how this is supposed to work so that's the idea of three arms here, but now, these three arms are mounted on a plate, which can rotate. 235 00:34:11,220 --> 00:34:24,720 Piotr Chrusciel: So therefore by rotating it, you can change the height difference between the beams and therefore measure, the response as a function of the height difference. 236 00:34:25,770 --> 00:34:29,790 Piotr Chrusciel: Now there's a lot of challenges here one of the challenge is a. 237 00:34:31,140 --> 00:34:35,250 Piotr Chrusciel: Nice say same same says make noise isolation. 238 00:34:36,420 --> 00:34:50,280 Piotr Chrusciel: or noise coming from vibrations introduced by moving the system and the collaboration part of the collaboration, who we thought. 239 00:34:51,450 --> 00:35:10,020 Piotr Chrusciel: is going to take take care of this part of the experiment was the analogous not valid, and it was a one of the pillars of the Lego experiments and knows everything about this thing, so we will be using the whole expertise of of Lego for this aspect of the standardization. 240 00:35:11,160 --> 00:35:11,550 Piotr Chrusciel: well. 241 00:35:13,050 --> 00:35:29,430 Piotr Chrusciel: This another group that was supposed to collaborate we hoped we're going to operate on this experiment is group of guys in Russia, because in Russia is in the brown bike metrology Institute, so this is the. 242 00:35:31,260 --> 00:35:31,740 Piotr Chrusciel: End of. 243 00:35:32,910 --> 00:35:56,250 Piotr Chrusciel: The oldest Nada Germany they have the most precise clocks that there are in Germany and therefore probably on us and the idea is that we're going to use this most precise clocks Germany, the information from these clocks sitting in branch bike will be sent to us through a. 244 00:35:58,200 --> 00:35:58,980 Piotr Chrusciel: fiber link. 245 00:36:00,270 --> 00:36:03,090 Piotr Chrusciel: And what's the point of of this. 246 00:36:07,410 --> 00:36:09,330 Piotr Chrusciel: signal from branch side. 247 00:36:10,680 --> 00:36:12,030 Piotr Chrusciel: This is a little bit like. 248 00:36:13,170 --> 00:36:13,800 Piotr Chrusciel: Active. 249 00:36:15,780 --> 00:36:20,160 Piotr Chrusciel: adaptive optics in astrophysics right so. 250 00:36:21,300 --> 00:36:26,880 Piotr Chrusciel: When you look at stars this noise coming from that was here and there is no way. 251 00:36:28,170 --> 00:36:33,480 Piotr Chrusciel: But if you can measure how much noise, there is, you can adapt your. 252 00:36:35,190 --> 00:36:52,200 Piotr Chrusciel: device to subtract this noise to get rid of this month and so that's the idea here, each of these arms, so we have three arms, you know or interferometer and we're going to use the timing coming from Bausch fight to. 253 00:36:53,760 --> 00:36:56,970 Piotr Chrusciel: going to well first is our fiber. 254 00:36:58,260 --> 00:37:08,160 Piotr Chrusciel: optical fibers optical fibers multiplex so you can send simultaneously a lot of various frequencies there so you'll be sending the. 255 00:37:09,870 --> 00:37:12,450 Piotr Chrusciel: Frequency that will be interested in will be. 256 00:37:13,740 --> 00:37:34,200 Piotr Chrusciel: For the detection will be one thing and the frequency stabilizing the arms would be another thing, so this signal coming from these virtual clocks from branch Mike will be measuring how much noise varies at a given moment of time in the fiber. 257 00:37:35,640 --> 00:38:00,120 Piotr Chrusciel: And so, this is done by setting up a another small arm in different metric arm and comparing the signal in the long arm with the very small one, and various something called I think doppler cavities or something like that which can be the news to in real time modify your. 258 00:38:01,830 --> 00:38:04,950 Piotr Chrusciel: The properties of your web guide to get rid of this. 259 00:38:06,810 --> 00:38:16,470 Piotr Chrusciel: Of this noise right so, so this is how this standardization of the arms would have been working here. 260 00:38:18,870 --> 00:38:21,330 Piotr Chrusciel: So what else can I say here. 261 00:38:22,470 --> 00:38:24,840 Piotr Chrusciel: Well, and so that's. 262 00:38:26,640 --> 00:38:39,330 Piotr Chrusciel: Two issues here, so one is to make the whole thing run, we discussed collide, which is enough to think, to start with, and once this is done, the next step would be to select single photons. 263 00:38:40,380 --> 00:38:50,430 Piotr Chrusciel: And to make the experiment with single photons and then it goes even better use various of entangled photons in there. 264 00:38:51,540 --> 00:38:57,180 Piotr Chrusciel: So i'm not going to tell you about single sign on single foreign sources you'd need to. 265 00:38:58,620 --> 00:39:03,000 Piotr Chrusciel: Feed voted for this i'm not going to tell you about single for detection. 266 00:39:04,650 --> 00:39:10,980 Piotr Chrusciel: So that's a story in itself, but let me tell you something about this. 267 00:39:12,690 --> 00:39:16,110 Piotr Chrusciel: difference between what happens in this machine. 268 00:39:17,760 --> 00:39:28,170 Piotr Chrusciel: When you send classical light, as opposed to quantum light so when you're sending classical light in here well and you get. 269 00:39:29,370 --> 00:39:39,930 Piotr Chrusciel: facelifts then love, if you could get a full face if of buyer would just go from seeing something to seeing nothing and that's it I do see. 270 00:39:40,260 --> 00:39:48,810 Piotr Chrusciel: Interference fringes which go dark or or other why we're not going that far is to pay going to tend to minus five rounds, or something like that, but. 271 00:39:51,360 --> 00:39:56,880 Piotr Chrusciel: But that's essentially what happens now, when you're solving sending photons it's a little different. 272 00:39:58,230 --> 00:40:05,910 Piotr Chrusciel: In particular, becomes interesting when you use something called noon states so. 273 00:40:07,440 --> 00:40:24,750 Piotr Chrusciel: This is our mass sender interferometer you sending entangled pairs of photon the machine right, so this is our lower arm, this is our higher arm, this is the detection point now so and you put. 274 00:40:25,770 --> 00:40:37,290 Piotr Chrusciel: So the state which is traveling here is either an photons in the arm a and non in be or. 275 00:40:38,730 --> 00:40:45,450 Piotr Chrusciel: And photons in the arm D and non in the arm a line until. 276 00:40:48,090 --> 00:41:03,120 Piotr Chrusciel: Each of the photons here is coming itself from a product denser production space of integral photons, which means that every individual photon in his own hilarious he speaks up. 277 00:41:03,720 --> 00:41:16,260 Piotr Chrusciel: Face delta Phi when it goes to the machine and because these are product states if you have any photons you're going to get a face, which is not delta Phi but you're going to get n times. 278 00:41:17,400 --> 00:41:26,670 Piotr Chrusciel: So if you manage to control your input noon states, we say n equal to, then, instead of having. 279 00:41:27,690 --> 00:41:28,470 Piotr Chrusciel: Phase shift. 280 00:41:29,490 --> 00:41:37,710 Piotr Chrusciel: Of delta Phi at the output you're going actually do have a face to the other side output if. 281 00:41:38,160 --> 00:41:44,490 Piotr Chrusciel: This year is correct right, so if our understanding of the way that natural equations couple to occur metric is correct. 282 00:41:44,910 --> 00:42:00,150 Piotr Chrusciel: And if quantum fields here is correct, then this is what we should observe and the claim is that well my colleagues here will be able to do something like that, given enough money to to do the experiment. 283 00:42:01,470 --> 00:42:02,550 Piotr Chrusciel: Good so that. 284 00:42:04,200 --> 00:42:07,650 Piotr Chrusciel: Yes, so this is the story about yeah so the. 285 00:42:08,670 --> 00:42:20,280 Piotr Chrusciel: Phase shift actually gets doubled and steady feel very continuously the height, then you get a curve, which actually is double the period yeah. 286 00:42:22,350 --> 00:42:24,030 Piotr Chrusciel: Good so. 287 00:42:25,200 --> 00:42:26,730 Piotr Chrusciel: This and the. 288 00:42:28,350 --> 00:42:43,260 Piotr Chrusciel: Experimental part of this talk and because when you can imagine i'm not sitting in the lab and doing all these manipulations with quantum optics but my part of this experiment was actually to do some calculations, so let me just. 289 00:42:44,490 --> 00:42:49,830 Piotr Chrusciel: show you how how we can how I do this, and for this, let me change. 290 00:42:52,410 --> 00:42:54,690 Piotr Chrusciel: Let me change my screen. 291 00:42:56,220 --> 00:42:57,240 Piotr Chrusciel: This one oh. 292 00:42:58,950 --> 00:42:59,250 Piotr Chrusciel: Good. 293 00:43:00,870 --> 00:43:03,840 Piotr Chrusciel: Yes, so how do we calculate all this. 294 00:43:05,520 --> 00:43:06,210 Piotr Chrusciel: So now. 295 00:43:07,740 --> 00:43:14,340 Piotr Chrusciel: i'm not sure i'm doing each time, by the way, I still have a 15 minutes or something like that what's the standard. 296 00:43:15,540 --> 00:43:23,100 Piotr Chrusciel: Yes, yes, it means okay good, well, I get somewhere so so we're looking optical fibers and. 297 00:43:24,780 --> 00:43:29,100 Piotr Chrusciel: We want to use affordable thanks so. 298 00:43:30,900 --> 00:43:42,990 Piotr Chrusciel: off the shelf high quality optical fibers the non magnetic so they have permeability called new one, and they have a permit Nativity excitement and square. 299 00:43:44,370 --> 00:43:45,030 Piotr Chrusciel: So. 300 00:43:46,680 --> 00:43:47,370 Piotr Chrusciel: The way. 301 00:43:48,930 --> 00:43:52,830 Piotr Chrusciel: They look is following there is a core, which is. 302 00:43:54,540 --> 00:44:11,370 Piotr Chrusciel: made of glass with a certainly certain refractive index say and one is the cladding which has another refractive index and two and one is louder than two that there is a buffer zones attack it, and this is what you have your in your. 303 00:44:12,900 --> 00:44:17,580 Piotr Chrusciel: When your fiber TV comes to your room or fighter fiber. 304 00:44:19,110 --> 00:44:20,280 Piotr Chrusciel: Internet providers. 305 00:44:21,570 --> 00:44:30,150 Piotr Chrusciel: Well, let me call row the radius of the core now the radius of the core is comparable to the optical wavelengths that these links, want to have. 306 00:44:31,290 --> 00:44:45,930 Piotr Chrusciel: Well, once you have means that there is a typical low last window, which you want to exploit and so the radius is comparable to to the optical way wavelengths so. 307 00:44:46,830 --> 00:45:01,290 Piotr Chrusciel: Typical would be five micrometres the cladding will be typically hundred micrometres and, if you want to model, this is actually as good as to assume that discarding goes to infinity. 308 00:45:01,770 --> 00:45:11,430 Piotr Chrusciel: Because the decay of the fields in the cladding is exponential with a characteristic skate like dictated by by the. 309 00:45:13,410 --> 00:45:35,430 Piotr Chrusciel: wavelength, so when you get to the boundary of the cladding your E to minus 20 times the initial signal which is as good to zero, as it gets as far as the experiments are concerned, so, in other words the model is a step index fiber and one here and to hear and. 310 00:45:36,600 --> 00:45:37,980 Piotr Chrusciel: The cladding goes to infinity. 311 00:45:39,270 --> 00:45:52,110 Piotr Chrusciel: So he and b are in a new new which is closed DNA are in a displacement vectors, in other words in other and asymmetric. 312 00:45:52,740 --> 00:46:00,750 Piotr Chrusciel: Data now controversy and answer which satisfies the zero diverted equation, in the absence of charges and currents. 313 00:46:01,230 --> 00:46:14,280 Piotr Chrusciel: And you have the constitutive equations which tell you our F bar in a linear dielectric linear homogeneous electric then that's the relationship where. 314 00:46:14,820 --> 00:46:29,220 Piotr Chrusciel: You is this magnetic constant and this gamma here is something called the optical metric so the optical metric is just a spacetime metric plus a correction involving the. 315 00:46:31,080 --> 00:46:33,990 Piotr Chrusciel: refraction index and the. 316 00:46:35,250 --> 00:46:43,230 Piotr Chrusciel: Rest they for velocity of the medium, so this is your mo is the unit vector. 317 00:46:45,180 --> 00:46:59,940 Piotr Chrusciel: you're describing the rest reign of the medium, and this is called the optical metric or the golden metric, and so the equations you wanted to solve this D F equals zero and divergence of a bar equals zero with this region here. 318 00:47:01,350 --> 00:47:15,030 Piotr Chrusciel: Now the setup we're interested in for the experiment is just a week, possibly turning gravitational field so come a genius at the scale of the lab time independent at the scale of the lab. 319 00:47:16,320 --> 00:47:24,330 Piotr Chrusciel: Was newtonian metric so the mikulski metric and correction, where this is the connector Delta. 320 00:47:25,620 --> 00:47:29,970 Piotr Chrusciel: This way of writing it actually i've learned from from my student. 321 00:47:31,020 --> 00:47:36,120 Piotr Chrusciel: And i've never seen this elsewhere so but that's how you can write it was newtonian. 322 00:47:37,230 --> 00:47:40,740 Piotr Chrusciel: gravitational metric is a chronic a delta and. 323 00:47:41,820 --> 00:47:43,350 Piotr Chrusciel: One on the surface of the US. 324 00:47:44,610 --> 00:47:46,440 Piotr Chrusciel: to five years older than minus nine. 325 00:47:47,460 --> 00:48:07,380 Piotr Chrusciel: And it's gradient is dental minus 16 by meter right if you make this unit less than the gradient wil wheaton minus 16 by meter So if you write down the equations that I showed you in their full glory in this metric you see that terms, involving squares or fi. 326 00:48:08,580 --> 00:48:15,450 Piotr Chrusciel: or derivatives of fi or secondary piece of pie, which will appear there if you just try these two equations and. 327 00:48:17,160 --> 00:48:18,450 Piotr Chrusciel: blow your way through them. 328 00:48:19,500 --> 00:48:28,560 Piotr Chrusciel: Then, then these terms are by seven or more orders of magnitude smaller than the one which on you have fine. 329 00:48:30,120 --> 00:48:37,110 Piotr Chrusciel: So So these are the equations you, you have to solve it, then, if you neglect this all this arrow terms. 330 00:48:38,580 --> 00:48:42,390 Piotr Chrusciel: These are so so these dust. 331 00:48:43,530 --> 00:48:53,010 Piotr Chrusciel: Excellent times, he these are just new times, he within this is raised with the fat metric, the only thing you do to. 332 00:48:54,060 --> 00:49:06,480 Piotr Chrusciel: get to this form, is that these fields are not the fields that you learned in your special relativity cause how you extract them from dispensers, but you have to. 333 00:49:06,990 --> 00:49:19,260 Piotr Chrusciel: feel it to Western definitions so include some metric factors in the definition of this of this fields but, at the end that's the system of equations you get. 334 00:49:20,130 --> 00:49:29,040 Piotr Chrusciel: And, of course, if you're in mikulski space time this is gone and you just get your usual Maxwell equations without any charges. 335 00:49:29,520 --> 00:49:38,640 Piotr Chrusciel: And you say, well, but of course if it's that simple than I don't have to do much work, because I can just reach scale. 336 00:49:39,360 --> 00:49:55,080 Piotr Chrusciel: Time absorb this into time, or in other words absorb this factor this factor is constant we seen your wave guide, so you can absorb this factor in the definition of amiga and use everything you know about wave guides in. 337 00:49:57,960 --> 00:50:03,210 Piotr Chrusciel: In flat bed space time just to get all the effects well this affected is. 338 00:50:05,460 --> 00:50:06,660 Piotr Chrusciel: A warning here, though. 339 00:50:07,830 --> 00:50:17,700 Piotr Chrusciel: If you didn't know that the right equations have a to find a here, but you said, well, let me just take the equations where I don't have these. 340 00:50:18,810 --> 00:50:25,230 Piotr Chrusciel: Five factors here, but they have a time, including here, and I know that a different time. 341 00:50:25,890 --> 00:50:41,160 Piotr Chrusciel: heights time flows differently so I just we scale, the time at different heights and they get the right equations that would be wrong, because if you did that you'll get one minus five here, instead of one minus 259 so somehow. 342 00:50:41,940 --> 00:50:42,330 Abhay Vasant Ashtekar: The way this. 343 00:50:42,780 --> 00:50:45,360 Abhay Vasant Ashtekar: Guy this was a kind of mistake that Einstein first made. 344 00:50:45,780 --> 00:50:46,680 Abhay Vasant Ashtekar: This really. 345 00:50:46,740 --> 00:50:47,490 Piotr Chrusciel: I don't know. 346 00:50:47,760 --> 00:50:59,460 Abhay Vasant Ashtekar: I don't the bending of light, because that is five factor comes in both spatial metric and in the in the time metric and he only took it in the time metric so. 347 00:50:59,610 --> 00:51:03,600 Piotr Chrusciel: Well i'm not aware that he solved the Maxwell equations for he's. 348 00:51:03,690 --> 00:51:04,920 Abhay Vasant Ashtekar: Like, no, no, no, no, no. 349 00:51:05,550 --> 00:51:08,280 Abhay Vasant Ashtekar: Just fighting for the yeah just longing for the Judas and. 350 00:51:08,760 --> 00:51:09,240 Piotr Chrusciel: This is. 351 00:51:10,320 --> 00:51:15,450 Piotr Chrusciel: This is idealize for the same reason that you get a factor of two, namely that the spatial matrix also changes which you have. 352 00:51:15,720 --> 00:51:33,690 Abhay Vasant Ashtekar: absorbed it in the in the calculations absorb it in the in the time time part of you know, because metric as one minus to a more one man is potential times P squared minus D R squared divided by one monster maura so that is what is causing all this. 353 00:51:34,770 --> 00:51:40,290 Piotr Chrusciel: So I know what what you're talking about and I was wondering whether one can actually. 354 00:51:41,550 --> 00:51:58,410 Piotr Chrusciel: pinpoint it as the same mistake it's not clear to me, but it's it's serving the same spirit right Okay, the same spirit that if you do something too fast here you're going to do it wrong so well that's not a big achievement any way to get this factor of two here, but so then. 355 00:52:01,410 --> 00:52:04,710 Piotr Chrusciel: There is some details i'm going to explain your. 356 00:52:06,090 --> 00:52:19,530 Piotr Chrusciel: More precisely what the details, but Silva calculation in mycoskie space timestamp is not calculating this data factor, and if you didn't have this factory here, the result would be beaten proportional to end on. 357 00:52:20,460 --> 00:52:27,270 Piotr Chrusciel: AMI guys the frequency of light to get here and and bar is neither the Fermi to be the. 358 00:52:29,250 --> 00:52:37,860 Piotr Chrusciel: refraction index of the core know the refraction index of the cladding that something which you need to calculate and. 359 00:52:39,210 --> 00:52:50,490 Piotr Chrusciel: that's the end and you get this formula and maybe we'll tell you how we calculate this in a few minutes, back then, you say well just looking at this equation, all you have to do is. 360 00:52:51,000 --> 00:53:07,080 Piotr Chrusciel: Well, the time is down here right, so this is essentially this factor one minus two Pfizer rescaling of frequency, so this is the effect, and if you and that's how you can get this delta Phi formula that I. 361 00:53:08,370 --> 00:53:11,070 Piotr Chrusciel: showed you in my previous slides but. 362 00:53:11,520 --> 00:53:13,950 Abhay Vasant Ashtekar: But the five depends on on space, I mean that was. 363 00:53:14,100 --> 00:53:18,960 Piotr Chrusciel: Like Okay, so now so so, how does this work right so now, so you have these two. 364 00:53:21,540 --> 00:53:36,720 Piotr Chrusciel: two arms of the interferometer and, of course, part of this thing is setting up your local inertial frame in which five zero me second say, well, I adjust my coordinate system or I. 365 00:53:37,530 --> 00:53:49,110 Piotr Chrusciel: calibrate may frequency had the lower part of the arm so maybe you guys done my frequency, but this whole thing is my frequency of your heart of the arm and then I compare it with the. 366 00:53:50,130 --> 00:53:59,940 Piotr Chrusciel: Frequency the higher arm using this formula and then this fight he's actually the difference of potentials between these two ones that's how it works. 367 00:54:01,050 --> 00:54:11,400 Piotr Chrusciel: So the summary of all these calculations, is following you take Maxwell equations in a wave right you ignore five Square, you cannot defy you know Vito five. 368 00:54:12,780 --> 00:54:17,100 Piotr Chrusciel: Both within the wave guide right so of course within the Web guy that's. 369 00:54:19,680 --> 00:54:20,760 Piotr Chrusciel: If it straight. 370 00:54:22,440 --> 00:54:36,210 Piotr Chrusciel: there's no room it's so small that there's no room for violations of rights, but when moving by one meter you also ignore this right, so all these gifts not measurable corrections, one could actually do this estimate indigo. 371 00:54:37,230 --> 00:54:46,590 Piotr Chrusciel: What would be the contribution to this effect well there's something that are they already mentioned well the. 372 00:54:47,160 --> 00:55:00,300 Piotr Chrusciel: Changing the way vector is not the same as getting the phase shift, because the metric between up and down is different, so if you move something here, and this thing is rigid. 373 00:55:00,690 --> 00:55:08,490 Piotr Chrusciel: Then the endpoint will not be have the same coordinate so you have to take this into account so there's an extra. 374 00:55:08,970 --> 00:55:19,980 Piotr Chrusciel: That that's why this formula I showed you at the beginning that the phase shift is length times the difference of pita is wrong, you still have to take into account the difference of geometry. 375 00:55:21,930 --> 00:55:32,820 Piotr Chrusciel: And, and now the other effects, you have to take care of because the radius of the wave guide changes, when you move it to coordinate radius and. 376 00:55:34,380 --> 00:55:42,870 Piotr Chrusciel: And maybe there are some other effects, I mean Dee da so So what are the effects, one is from the cording mine so it's not as straight. 377 00:55:44,550 --> 00:55:48,210 Piotr Chrusciel: Wave like it's a Korean wave guide and therefore. 378 00:55:49,320 --> 00:56:02,250 Piotr Chrusciel: As the photon goes it's still moving in a gravitational field and the story is a say, maybe, if you move the things that one meter apart because will be 30 centimeters or something like that. 379 00:56:03,810 --> 00:56:22,320 Piotr Chrusciel: This could give an effect well the spoiler is that we can be that build a model of coining this produces sideburns in this way right and the amplitude of the sidebar too small too small to be measures, this too is missing in oh actually here. 380 00:56:23,760 --> 00:56:31,860 Piotr Chrusciel: So she'll be calling, you can do the calculation to take into account recording and it wouldn't matter, essentially, what matters is. 381 00:56:33,720 --> 00:56:44,220 Piotr Chrusciel: the height of the Center of this coin now, what about rotation effects, what else is rotating around this access is rotating around the sun. 382 00:56:44,760 --> 00:57:01,410 Piotr Chrusciel: And the spoiler is that the effect of this is larger by three orders of magnitude and the effect we wanted to measure the effect of wanting me to change a fight between the arms is by three orders of magnitude smaller than the rotation of us going to. 383 00:57:02,790 --> 00:57:03,960 Piotr Chrusciel: come to that in a minute. 384 00:57:05,610 --> 00:57:06,060 Piotr Chrusciel: well. 385 00:57:07,530 --> 00:57:14,250 Piotr Chrusciel: If you're over enthusiastic you could think wow maybe I could make a gravitational wave to take you out of bed. 386 00:57:16,890 --> 00:57:23,430 Piotr Chrusciel: And so, so you can calculate all the time, so I try to. 387 00:57:24,480 --> 00:57:29,010 Piotr Chrusciel: I could try to tell you how to calculate this but, all I can just maybe give you the. 388 00:57:32,130 --> 00:57:42,150 Piotr Chrusciel: bottom line yeah, let me just mentioned to you okay so i'm not going to run you through the calculations, but let me just tell you the following. 389 00:57:45,090 --> 00:58:00,210 Piotr Chrusciel: there's a calculation, which leads to these things, and because there's a participation scheme, the effects of the gravitational potential that will be measured by comparing phase between these arms and the effect of rotation of us are additive. 390 00:58:01,260 --> 00:58:12,090 Piotr Chrusciel: So you can calculate them separately, and so what you can do is, as you take rotation think take mikulski spacetime make it rotate and repeat this calculation. 391 00:58:13,440 --> 00:58:16,860 Piotr Chrusciel: That I didn't show you what it is so. 392 00:58:18,180 --> 00:58:24,480 Piotr Chrusciel: One way of doing this is guilt rotating coding, so you get something which is called the bond metric and so. 393 00:58:25,710 --> 00:58:35,370 Piotr Chrusciel: you've solved in a perverted by keep scheme these equations with now this Omega being a rotation victor. 394 00:58:36,420 --> 00:58:36,840 Piotr Chrusciel: and 395 00:58:38,970 --> 00:58:42,660 Piotr Chrusciel: After some work that's what you get. 396 00:58:43,980 --> 00:58:44,490 Piotr Chrusciel: That. 397 00:58:46,050 --> 00:58:49,620 Piotr Chrusciel: The accumulated facelift will be will have this part. 398 00:58:50,760 --> 00:59:03,210 Piotr Chrusciel: Which is coming from the rotation of us so um you guys the frequency of the of light capital me guys the frequency rotation of us, the one over 24 hours. 399 00:59:03,930 --> 00:59:23,820 Piotr Chrusciel: Cisco is, what do you think it is casita is the angle between the plane of your interferometer So if you want to think about this interferometer into her arms here so tita is the angle between the plane of the interferometer and the rotation access so by orienting your. 400 00:59:24,930 --> 00:59:42,780 Piotr Chrusciel: machine in your lab appropriately, you can either get rid of this by making this angle to be zero so you're aligned the plane of your machine with the rotation of the earth so let's in Vienna, would be a summer by somewhere out there. 401 00:59:44,160 --> 00:59:44,580 Piotr Chrusciel: and 402 00:59:45,930 --> 00:59:46,560 Piotr Chrusciel: All you can. 403 00:59:48,030 --> 00:59:54,270 Piotr Chrusciel: So you can make adventure can maximize it or you can vary this angle and actually check whether this formula is correct. 404 00:59:55,500 --> 00:59:59,250 Piotr Chrusciel: So here as they're young close by interferometer that's l times. 405 01:00:00,480 --> 01:00:02,130 Piotr Chrusciel: difference of height it's there. 406 01:00:03,720 --> 01:00:18,300 Piotr Chrusciel: And, and so the gravitational phase shift formula, as I said, is three orders of magnitude smaller than this thing that's the equivalent formula for. 407 01:00:19,440 --> 01:00:24,420 Piotr Chrusciel: One meter displacement between the arms so. 408 01:00:26,280 --> 01:00:35,370 Piotr Chrusciel: Now this several arms machine is a bit expensive and so we're currently trying to get money to build it. 409 01:00:36,450 --> 01:00:48,870 Piotr Chrusciel: But this measuring rotation of using simple photons seems like an interesting and challenging thing first it's actually not trivial to do and. 410 01:00:50,760 --> 01:01:07,680 Piotr Chrusciel: Love think sounds like nonsense, just to ask and tongue entangled photon states to measure the rotation of us, but well why don't we do it if we can and that's what's being built now into that place of my colleagues are right now building. 411 01:01:08,700 --> 01:01:12,330 Piotr Chrusciel: Simple version of this machine which is just designed to. 412 01:01:13,890 --> 01:01:14,280 Piotr Chrusciel: To. 413 01:01:15,960 --> 01:01:33,000 Piotr Chrusciel: measure this effect, first on continuous light and then on single photons and then entangled photons, and this is an experiment which is certainly going to take place, whether this one is going to do it, while it's we missing a couple of million euros, so you. 414 01:01:34,260 --> 01:01:40,230 Piotr Chrusciel: know somebody generous who wants to contribute to taking quantum. 415 01:01:42,450 --> 01:01:49,050 Piotr Chrusciel: field theory in caps facetime and with a few million euros, then we could start. 416 01:01:50,250 --> 01:01:51,420 Piotr Chrusciel: Doing this experiment. 417 01:01:54,210 --> 01:01:57,990 Piotr Chrusciel: last thing I wanted to say that we did the calculation for gravitational waves. 418 01:01:59,700 --> 01:02:01,800 Piotr Chrusciel: Then this has. 419 01:02:03,960 --> 01:02:14,100 Piotr Chrusciel: This is interesting because you could, if it worked, you could have a gravitational wave detector invest up, it would be quite a bit cheaper than. 420 01:02:15,210 --> 01:02:16,470 Piotr Chrusciel: machines like Lego. 421 01:02:17,670 --> 01:02:29,490 Piotr Chrusciel: The most interesting part as i'm concerned is that if you put three detectors on your desktop one looking this way, the second like that, and they said, like that then out of. 422 01:02:30,390 --> 01:02:39,750 Piotr Chrusciel: This machine you're going to get information about what the wave is coming from, without having to ask you, colleagues in, on the other side of the world, just. 423 01:02:41,160 --> 01:02:43,440 Piotr Chrusciel: To try to help you with this. 424 01:02:44,550 --> 01:02:58,290 Piotr Chrusciel: Now, the first proposal of wave guy gravitational wave detector is going back to bragging skin minsky in two papers in 72 and 75 they proposed ring configurations. 425 01:02:59,340 --> 01:03:13,920 Piotr Chrusciel: In with a frequency, which would be in resonance with the frequency of one of the neutron stars and then use this to measure gravitational waves for this, and the idea was dismissed by in this. 426 01:03:15,300 --> 01:03:23,760 Piotr Chrusciel: Historic monumental proposal of Lego bylines is hows and whys and we'd come because of noise and losses now. 427 01:03:25,020 --> 01:03:30,120 Piotr Chrusciel: Meanwhile, we have a lot of progress with optical fibers losses, however, remain. 428 01:03:32,280 --> 01:03:56,760 Piotr Chrusciel: If you wanted to get lygo gravitational wave accuracy, you need a lot of power, and if you put a lot of power in a fiberglass melts the fiberglass or it there is so much scattering that this kills the idea with today's wave guide, so you can do the calculation and but, but you can't. 429 01:03:57,810 --> 01:04:12,300 Piotr Chrusciel: Do a detective today, but while Maybe you can do it in 20 years and therefore it's useful to do the calculation, and this is something that my student Thomas meeting did and. 430 01:04:13,230 --> 01:04:23,970 Piotr Chrusciel: He has a formula for for the face shift and so forth, but I think i'm going to stop here, and maybe take questions if there are any. 431 01:04:35,760 --> 01:04:36,750 Abhay Vasant Ashtekar: So can I ask a question. 432 01:04:37,470 --> 01:04:37,740 yeah. 433 01:04:39,540 --> 01:04:40,110 Abhay Vasant Ashtekar: So. 434 01:04:41,610 --> 01:04:47,460 Abhay Vasant Ashtekar: I mean he's really the fundamental question it says basic question which I got I mean. 435 01:04:48,330 --> 01:04:59,850 Abhay Vasant Ashtekar: I mean you made a big distinction between classical light and quantum light and so on, but all your considerations for electromagnetic waves really classical electromagnetic waves propagating in them in a. 436 01:04:59,880 --> 01:05:00,300 Piotr Chrusciel: bright. 437 01:05:00,390 --> 01:05:01,590 Piotr Chrusciel: And I want you to. 438 01:05:01,680 --> 01:05:05,070 Piotr Chrusciel: This calculations which I didn't show you how to do. 439 01:05:06,360 --> 01:05:07,920 Piotr Chrusciel: You want is them. 440 01:05:08,940 --> 01:05:09,450 Piotr Chrusciel: Using. 441 01:05:10,620 --> 01:05:21,960 Piotr Chrusciel: I would say, vanilla quantization were some clarifications in expansion of the field become operators and and just start with them so. 442 01:05:22,020 --> 01:05:28,530 Abhay Vasant Ashtekar: That that but point is that the the inner part in the photo here but space, I feel like the complex structure that you need to introduce. 443 01:05:29,820 --> 01:05:37,530 Abhay Vasant Ashtekar: That knows about the metric like in the static picture Eric knows about the knowledge, the killing of activity which is really contain in five. 444 01:05:39,390 --> 01:05:50,160 Abhay Vasant Ashtekar: And so, therefore, the norm itself will have the information also fi, and so there will be an additional contribution that comes up. 445 01:05:50,700 --> 01:06:03,090 Abhay Vasant Ashtekar: When you actually look at the interference term because you like to take the photon in the product somehow in all these things on there, and I think that I just wanted to make sure that that was carefully that. 446 01:06:03,120 --> 01:06:09,510 Piotr Chrusciel: No, so this part hasn't been done carefully at so so we did the classical calculations and we're. 447 01:06:09,510 --> 01:06:20,190 Piotr Chrusciel: On started looking where we know the general formula is how these noon States work and stuff like that, but as you're saying you still need to calculate the face and weather. 448 01:06:20,220 --> 01:06:20,730 Abhay Vasant Ashtekar: yeah the fourth. 449 01:06:21,960 --> 01:06:31,590 Abhay Vasant Ashtekar: One article for today yeah so i'll be happy, I mean it's reasonably straightforward so i'll be happy to talk to you in detail if you're interested about how to complete this thing. 450 01:06:31,950 --> 01:06:39,330 Abhay Vasant Ashtekar: Because they may well be I would think that I would be surprised if there isn't some additional factor, because the photon in the product changes. 451 01:06:39,870 --> 01:06:48,960 Abhay Vasant Ashtekar: In the static space time, which is what you're considering appear and precisely by the factor of five and so there'll be some numerical coefficient just like this factor of two five verses five that you talked about. 452 01:06:49,710 --> 01:06:54,930 Abhay Vasant Ashtekar: That they may be something like that in the content, the idea, maybe they've all cancels out, but we should just do it right. 453 01:06:55,530 --> 01:07:04,050 Piotr Chrusciel: right, of course, this is your oven for this gravitational waves, which is certainly a level of classical lightened metric doesn't even have a killing vector here exactly. 454 01:07:04,080 --> 01:07:05,040 Piotr Chrusciel: I don't cause for. 455 01:07:06,180 --> 01:07:07,050 Piotr Chrusciel: Both for this. 456 01:07:07,410 --> 01:07:10,140 Piotr Chrusciel: Even for this rotation effect that would be relevant what you're saying. 457 01:07:11,580 --> 01:07:11,850 Abhay Vasant Ashtekar: Right. 458 01:07:11,940 --> 01:07:17,220 Abhay Vasant Ashtekar: Now, I think, maybe I mean we're to shortlist that Oliver are calculated again. 459 01:07:17,880 --> 01:07:28,080 Piotr Chrusciel: Well i'd be very happy to talk with you about it yeah and and especially with service my students to ISO and Thomas meeting is a. 460 01:07:28,620 --> 01:07:38,790 Piotr Chrusciel: And working on a PhD with me and he's an expert in all these things, and he just we just started looking at the quantum aspects now because we're about to finish the. 461 01:07:41,790 --> 01:07:49,020 Piotr Chrusciel: One one of papers about about these things Center Okay, you know what one of the problems here is a. 462 01:07:50,820 --> 01:07:51,300 Piotr Chrusciel: So. 463 01:07:52,410 --> 01:08:09,600 Piotr Chrusciel: As some of you might suspect I like a mathematical rigor and these kind of calculations, you get this error terms in the equations which you expect our of the order that they show up in the equations, but in fact it's. 464 01:08:10,920 --> 01:08:28,230 Piotr Chrusciel: anybody's guess so now discarding turns into equations and if you don't have some solid mathematical theorems behind it, you don't know whether they're really smaller as they should be, so this is very much kind of mathematical physics, which is a. 465 01:08:29,940 --> 01:08:35,220 Piotr Chrusciel: lot of hand waving which sounds reasonable from a physical point of view, but then I suppose that. 466 01:08:37,500 --> 01:08:42,780 Piotr Chrusciel: i'd love to see these things to be more rigorous than the calculations we've been doing. 467 01:08:44,190 --> 01:08:50,250 Abhay Vasant Ashtekar: I just wanted to say that I really want to express my admiration, because I know that kind of mathematical. 468 01:08:50,790 --> 01:09:02,400 Abhay Vasant Ashtekar: Productivity you do with my family and to go from there to you know worry about coils and rotations and so on, so forth, requires a huge understanding of film logical things I guess appreciation or. 469 01:09:02,940 --> 01:09:07,920 Piotr Chrusciel: Getting, as I said at the beginning, I mean don't spread about the information i'm giving. 470 01:09:10,500 --> 01:09:11,850 Piotr Chrusciel: Experimental talks. 471 01:09:12,900 --> 01:09:16,560 Piotr Chrusciel: My room my reputation will be just down the drain. 472 01:09:20,220 --> 01:09:20,970 Piotr Chrusciel: that's a different. 473 01:09:22,020 --> 01:09:23,880 Piotr Chrusciel: Part of a different one. 474 01:09:25,770 --> 01:09:26,760 Ivan Agullo: I have another question. 475 01:09:27,210 --> 01:09:27,540 Piotr Chrusciel: uh huh. 476 01:09:28,020 --> 01:09:33,210 Ivan Agullo: So pick, thank you for the for the dog, it was very, very clear and very entertaining so. 477 01:09:34,380 --> 01:09:40,650 Ivan Agullo: It was regarding the coin, that you mentioned, because I was thinking about that, and then you mentioned it. 478 01:09:41,400 --> 01:09:48,180 Ivan Agullo: But when you mentioned the coil you were taking into account the fact that light can go up and down when it goes. 479 01:09:48,600 --> 01:09:55,800 Ivan Agullo: But you didn't mention that light is also you know rotating is going around many, many, many times, so you know. 480 01:09:56,190 --> 01:10:08,040 Ivan Agullo: If you won the race frame of the of the libraries, I think the complicated because you know it goes around many, many times and and you didn't mention anything about that is that effect, going to. 481 01:10:08,490 --> 01:10:10,200 Piotr Chrusciel: Okay, so so. 482 01:10:12,060 --> 01:10:15,930 Piotr Chrusciel: that's a very interesting suggestion to see what there is some kind of. 483 01:10:16,950 --> 01:10:31,740 Piotr Chrusciel: Further effects coming from coding and but, so I have one answer would be that this effect will be the same as me makovsky space time, first, to start with, so you have a perturbation of the mikulski space time effects. 484 01:10:32,100 --> 01:10:42,570 Piotr Chrusciel: which must have been studied which and and so, if you move, you have your card here and meet your APP and this effects will be the same. 485 01:10:43,200 --> 01:10:56,640 Piotr Chrusciel: So if you want to compare what happens is these two cards, I think that the level of accuracy of the experiment, the this part of this coding effects will cancel. 486 01:10:57,990 --> 01:11:05,730 Piotr Chrusciel: particles is rotation that you're very justly mentioning we just cancel and the main effect would be coming from. 487 01:11:06,750 --> 01:11:24,630 Piotr Chrusciel: From the one who can create it so if you have a straight wave guide, you can actually right exact explicit solutions of the maximal equation, which correspond to this, if you have a cold, you cannot so you need to make approximation for calculations for this and. 488 01:11:27,150 --> 01:11:40,380 Piotr Chrusciel: Right so so a and then again, the question is how rigorous all this it hurts my heart to say it's not rigorous enough at the level, I would like to have it. 489 01:11:43,140 --> 01:11:50,820 Piotr Chrusciel: At least we had we can make a physically plausible calculation, which shows you what I told you. 490 01:11:51,810 --> 01:11:52,920 Ivan Agullo: Absolutely, thank you. 491 01:11:56,100 --> 01:11:57,540 Abhay Vasant Ashtekar: it's all decide that you want that. 492 01:11:59,550 --> 01:11:59,910 Abhay Vasant Ashtekar: Is it. 493 01:12:01,110 --> 01:12:12,030 Abhay Vasant Ashtekar: Is it possible to do the I mean I is what you're in mind is basically that these photons on, so to say, following a linear combination of the translation and the rotational killing vector. 494 01:12:14,760 --> 01:12:18,420 Piotr Chrusciel: Right now yeah so this I thought about this and. 495 01:12:19,980 --> 01:12:23,580 Piotr Chrusciel: tried with Bobby just to to do things about it but. 496 01:12:25,350 --> 01:12:29,820 Piotr Chrusciel: Just producing an exact solution, which we have these properties. 497 01:12:31,080 --> 01:12:32,640 Piotr Chrusciel: We couldn't right so. 498 01:12:33,750 --> 01:12:46,950 Abhay Vasant Ashtekar: But we will, if we don't produce exact solution is that what physical Is that a correct thing to say that the you should not use the linear combination of these two killing vectors certified positive negative frequency decomposition Is that what you are in mind you want. 499 01:12:47,850 --> 01:13:05,520 Piotr Chrusciel: And now I did I didn't know my baby when sure yeah so so at this stage we starting to understand the quantum theory of a straight way tonight and then we'll be building out their understanding it beyond this first naive. 500 01:13:07,680 --> 01:13:08,820 Piotr Chrusciel: approach that I mentioned. 501 01:13:09,510 --> 01:13:12,720 Abhay Vasant Ashtekar: But, but even Is that what you had in mind, or you had something else in mind. 502 01:13:13,140 --> 01:13:23,730 Ivan Agullo: But I don't know if I would say, a combination of two key factors, because the the rotation is not around you know around the earth or anything like that that will take us around the axis of their. 503 01:13:23,850 --> 01:13:28,140 Abhay Vasant Ashtekar: Of nobody just take it take it mikulski space, the first first approximation that was being said. 504 01:13:29,220 --> 01:13:33,720 Abhay Vasant Ashtekar: I think about dissolving mccaskey space don't don't worry about the earth at all. 505 01:13:35,460 --> 01:13:39,330 Ivan Agullo: Right, but the directory so far from a geodesic that I don't know. 506 01:13:41,850 --> 01:13:44,970 Ivan Agullo: If this combination will will will be exactly what I have in mind. 507 01:13:46,230 --> 01:13:57,870 Ivan Agullo: You know what I mean because you know if you go around a coil you know your thing be far from any type of the USA and and and I think taking that into account is going to be challenging. 508 01:13:59,250 --> 01:14:16,470 Piotr Chrusciel: But the sooner you're thinking about a card which as say half a meter diameter 30 centimeters or something like that well the way guide itself as a core of five micrometres so we talking about the curvature. 509 01:14:17,790 --> 01:14:24,210 Piotr Chrusciel: Going plants around being what six orders, five, six orders of magnitude right. 510 01:14:25,710 --> 01:14:30,120 Piotr Chrusciel: Different, in other words, you need to go 10 to six. 511 01:14:31,230 --> 01:14:44,040 Piotr Chrusciel: Radio to get to do the coding point and that's why even because the space time people just make approximations here and in mccaskey space time does the straight calling produces. 512 01:14:44,640 --> 01:15:05,580 Piotr Chrusciel: Losses so that's the main effect, you get a, in other words, this propagation a vector data gets an imaginary part which is losses, but other than that propagation at this level of approximation is the same. 513 01:15:07,800 --> 01:15:09,900 Piotr Chrusciel: But of course yeah this. 514 01:15:12,300 --> 01:15:17,580 Piotr Chrusciel: idea of having some kind of maybe topology can information from coding is very attractive. 515 01:15:22,590 --> 01:15:23,520 Jorge Pullin: Any other questions. 516 01:15:24,360 --> 01:15:29,040 wolfgang wieland: Maybe a question on the on the modes that are. 517 01:15:31,320 --> 01:15:33,600 wolfgang wieland: propagating along the fibers. 518 01:15:34,680 --> 01:15:37,110 wolfgang wieland: In optical in. 519 01:15:38,160 --> 01:15:47,640 wolfgang wieland: fiber optics phone has also the possibility to generate like higher angular momentum that propagate along the. 520 01:15:48,690 --> 01:15:55,770 wolfgang wieland: Along the fiber so could there be any effects coming from some sort of spin coupling. 521 01:15:59,700 --> 01:16:04,260 Piotr Chrusciel: cell, so this is a one of the steps of the calculation. 522 01:16:05,490 --> 01:16:06,330 Piotr Chrusciel: Where. 523 01:16:07,830 --> 01:16:23,940 Piotr Chrusciel: Some fields are have a quantum rotation number one so, so this is a disease along the way guide and TTS dangle along the way guide, and so this wave as it progresses, as this. 524 01:16:25,560 --> 01:16:30,900 Piotr Chrusciel: rotates along the way pride is low and the mode that. 525 01:16:31,530 --> 01:16:32,370 Piotr Chrusciel: My colleagues. 526 01:16:32,400 --> 01:16:54,390 Piotr Chrusciel: use for the experiments is typically one here and I don't think I remember why it is one, but I it's probably the one which has the the best these losses or something like that in the kind of settings they have in mind so you're using light that rotates in the wave guide as it progresses. 527 01:16:57,180 --> 01:17:04,230 Piotr Chrusciel: i'm not sure if it's this is related to your question, but that's it certainly built in this in these calculations. 528 01:17:08,670 --> 01:17:09,660 Jorge Pullin: Any other questions. 529 01:17:17,040 --> 01:17:18,390 Jorge Pullin: Okay let's Thank you again. 530 01:17:19,770 --> 01:17:23,220 Piotr Chrusciel: Thank you for listening and I hope you do is. 531 01:17:23,700 --> 01:17:24,270 Jorge Pullin: Like listening.