WEBVTT 1 00:00:08.480 --> 00:00:11.439 - Hello, and welcome to the Physics World weekly 2 00:00:11.439 --> 00:00:13.539 - podcast. I'm Hamish Johnston. 3 00:00:14.234 --> 00:00:17.135 - I'm very pleased to be joined from Japan 4 00:00:17.434 --> 00:00:18.655 - by two theoretical 5 00:00:19.035 --> 00:00:19.535 - physicists. 6 00:00:20.234 --> 00:00:22.015 - They are Ippei Danshita 7 00:00:22.714 --> 00:00:23.934 - of Kindai University 8 00:00:24.635 --> 00:00:25.614 - and Daichi 9 00:00:26.074 --> 00:00:26.574 - Kagemihara 10 00:00:27.480 --> 00:00:28.779 - at Chuo University. 11 00:00:29.879 --> 00:00:32.700 - They led a team who have gained important 12 00:00:33.079 --> 00:00:35.979 - insights into quantum mechanical tunneling 13 00:00:36.520 --> 00:00:38.939 - by doing remotely controlled experiments 14 00:00:39.640 --> 00:00:41.100 - on a Bose Einstein 15 00:00:41.399 --> 00:00:41.899 - condensate 16 00:00:42.655 --> 00:00:45.314 - that was located more than 8,000 17 00:00:45.695 --> 00:00:46.754 - kilometers away 18 00:00:47.054 --> 00:00:47.875 - in The US. 19 00:00:49.054 --> 00:00:50.195 - In our conversation, 20 00:00:50.814 --> 00:00:53.795 - Daichi and Ipe talk about the challenges 21 00:00:54.174 --> 00:00:56.754 - of making measurements using an apparatus 22 00:00:57.054 --> 00:00:58.990 - on the other side of the world. 23 00:00:59.770 --> 00:01:02.190 - And they also reveal what they've learned, 24 00:01:02.570 --> 00:01:04.829 - both about the physics of tunneling 25 00:01:05.609 --> 00:01:07.950 - and about how remote experiments 26 00:01:08.409 --> 00:01:09.629 - can help theorists 27 00:01:10.329 --> 00:01:11.629 - test their calculations. 28 00:01:13.025 --> 00:01:16.965 - The BEC platform they used is called Octant, 29 00:01:17.424 --> 00:01:19.685 - and it was created and operated 30 00:01:20.064 --> 00:01:21.045 - by the quantum 31 00:01:21.344 --> 00:01:22.564 - technology company 32 00:01:22.944 --> 00:01:23.444 - Inflexion 33 00:01:24.305 --> 00:01:26.005 - as Daichi explains. 34 00:01:34.250 --> 00:01:35.870 - Hi, Ibe and Daichi. 35 00:01:36.329 --> 00:01:37.630 - Welcome to the podcast. 36 00:01:38.810 --> 00:01:39.630 - Hi, Hamish. 37 00:01:40.064 --> 00:01:41.524 - Thank you very much for the invitation. 38 00:01:41.984 --> 00:01:44.484 - Hi, Hamish. Yeah. I'm Oren too. 39 00:01:45.104 --> 00:01:46.784 - Well, that's great. I'd like to thank both 40 00:01:46.784 --> 00:01:48.625 - of you for joining me today. It's... We're 41 00:01:48.625 --> 00:01:50.724 - we're recording this on a Friday afternoon, 42 00:01:51.265 --> 00:01:53.024 - and I think it's... What time is it 43 00:01:53.024 --> 00:01:56.950 - in Japan? Is it 04:30 or maybe 05:30? 44 00:01:57.569 --> 00:02:00.369 - So thanks thanks so much to you for, 45 00:02:00.930 --> 00:02:03.429 - for joining me so late in the day, 46 00:02:03.729 --> 00:02:04.950 - late in the week. 47 00:02:05.969 --> 00:02:07.829 - My first question is to, 48 00:02:08.370 --> 00:02:08.870 - Daichi. 49 00:02:09.585 --> 00:02:10.965 - You've used Inflexion's 50 00:02:11.665 --> 00:02:15.205 - Octant cloud based Bose Einstein condensate 51 00:02:15.665 --> 00:02:16.724 - for your research. 52 00:02:17.104 --> 00:02:18.004 - Can you describe 53 00:02:18.305 --> 00:02:19.365 - Octant? What 54 00:02:19.745 --> 00:02:20.724 - what does the system, 55 00:02:21.985 --> 00:02:23.604 - what does it comprise of? 56 00:02:24.199 --> 00:02:25.500 - Yeah. Octant is 57 00:02:25.960 --> 00:02:28.379 - a cloud based experimental platform, 58 00:02:29.479 --> 00:02:32.759 - that allows us to remotely perform experiment with 59 00:02:32.759 --> 00:02:33.979 - bose Einstein condensates, 60 00:02:34.360 --> 00:02:34.860 - BG. 61 00:02:36.114 --> 00:02:36.614 - Users 62 00:02:37.955 --> 00:02:38.614 - can submit 63 00:02:38.914 --> 00:02:39.974 - experimental protocols, 64 00:02:40.834 --> 00:02:42.215 - through a web interface 65 00:02:42.594 --> 00:02:45.334 - or for advanced controls using Python. 66 00:02:45.955 --> 00:02:48.449 - Obtained then carries out experiments, 67 00:02:50.030 --> 00:02:52.289 - and return measures data for analysis. 68 00:02:52.909 --> 00:02:54.449 - Octant provide two 69 00:02:54.829 --> 00:02:55.329 - experiments, 70 00:02:55.789 --> 00:02:57.729 - the preparation of BC and 71 00:02:58.590 --> 00:03:00.289 - the manipulation of its dynamics. 72 00:03:00.905 --> 00:03:02.685 - In the preparation part, 73 00:03:02.985 --> 00:03:03.485 - atoms, 74 00:03:03.944 --> 00:03:04.444 - atoms, 75 00:03:05.705 --> 00:03:07.965 - cooled down by so called evaporative 76 00:03:08.264 --> 00:03:08.764 - cooling. 77 00:03:09.384 --> 00:03:10.044 - We can 78 00:03:10.344 --> 00:03:12.284 - design this cooling schedule. 79 00:03:12.629 --> 00:03:13.689 - This allow us 80 00:03:14.229 --> 00:03:16.969 - to control the property of the prepared BC, 81 00:03:17.030 --> 00:03:17.689 - such as 82 00:03:18.069 --> 00:03:20.090 - temperature and on the set fractions. 83 00:03:20.709 --> 00:03:23.209 - The second type of experiment is to, 84 00:03:24.469 --> 00:03:26.490 - manipulate the BC in 85 00:03:27.344 --> 00:03:29.844 - in a harmonic trap. We can apply, 86 00:03:31.745 --> 00:03:33.125 - we can apply especially, 87 00:03:33.504 --> 00:03:36.245 - temporary varying potentials to drive 88 00:03:36.544 --> 00:03:37.844 - the dynamics of BC. 89 00:03:38.544 --> 00:03:39.284 - We also... 90 00:03:39.585 --> 00:03:40.724 - We can also take 91 00:03:41.620 --> 00:03:43.959 - images corresponding to the atomic density 92 00:03:44.659 --> 00:03:45.400 - by repeating 93 00:03:45.939 --> 00:03:47.639 - experiment with the same, 94 00:03:48.500 --> 00:03:49.560 - potential schedule, 95 00:03:50.580 --> 00:03:51.400 - while changing 96 00:03:51.699 --> 00:03:54.739 - the imaging time. We can study the real 97 00:03:54.739 --> 00:03:55.479 - time evolution 98 00:03:56.180 --> 00:03:56.840 - of the BC. 99 00:03:58.155 --> 00:03:58.794 - This is, 100 00:03:59.675 --> 00:04:02.074 - this is essentially what we did in our 101 00:04:02.074 --> 00:04:04.574 - research in in this... In our paper. 102 00:04:05.275 --> 00:04:07.694 - Aniopei, there's there's one thing that I've wondered 103 00:04:07.754 --> 00:04:10.014 - about this this remote control 104 00:04:10.395 --> 00:04:13.139 - BEC. Is there actually somebody there, 105 00:04:14.239 --> 00:04:15.780 - you know, at inflection, 106 00:04:16.800 --> 00:04:19.360 - twiddling the knobs for you? I mean, are 107 00:04:19.360 --> 00:04:21.759 - you telling somebody to set the experiment up, 108 00:04:21.759 --> 00:04:23.699 - and there's an actual person there? 109 00:04:24.104 --> 00:04:25.884 - Or is it all done, 110 00:04:26.425 --> 00:04:27.485 - you know, remotely, 111 00:04:28.425 --> 00:04:30.264 - if you see what I mean, with no 112 00:04:30.264 --> 00:04:31.324 - person involved, 113 00:04:32.104 --> 00:04:33.084 - at the actual 114 00:04:33.544 --> 00:04:35.324 - vacuum chamber with the BEC? 115 00:04:36.540 --> 00:04:38.779 - Yeah. That's actually a very good question, but 116 00:04:38.779 --> 00:04:39.279 - we 117 00:04:39.740 --> 00:04:41.360 - actually have never asked 118 00:04:41.819 --> 00:04:42.319 - the, 119 00:04:43.259 --> 00:04:43.759 - administrator 120 00:04:44.220 --> 00:04:46.000 - or this, experimental equipment. 121 00:04:47.180 --> 00:04:50.214 - So... But we we... Our guess is that, 122 00:04:51.654 --> 00:04:52.955 - well, things are automated, 123 00:04:54.134 --> 00:04:54.634 - actually. 124 00:04:55.334 --> 00:04:55.834 - But, 125 00:04:56.375 --> 00:04:56.875 - someone, 126 00:04:58.055 --> 00:05:00.394 - in charge of this experimental experiment 127 00:05:00.935 --> 00:05:02.795 - is there during the... 128 00:05:03.735 --> 00:05:04.455 - So during the, 129 00:05:05.540 --> 00:05:07.720 - time slot where we can do the experiment. 130 00:05:09.220 --> 00:05:09.720 - The... 131 00:05:10.339 --> 00:05:11.560 - I think so because 132 00:05:12.100 --> 00:05:15.379 - the... There is kinda limited time slot for 133 00:05:15.379 --> 00:05:17.939 - operating the octant, and this is actually business 134 00:05:17.939 --> 00:05:19.185 - time of The United States. 135 00:05:20.064 --> 00:05:21.524 - Mhmm. That's... Yeah. 136 00:05:23.105 --> 00:05:24.964 - That's how we see here. 137 00:05:25.985 --> 00:05:28.384 - I see. And and, Ipe, what are the 138 00:05:28.384 --> 00:05:28.884 - benefits 139 00:05:29.264 --> 00:05:29.925 - of doing 140 00:05:30.544 --> 00:05:31.044 - BEC 141 00:05:31.930 --> 00:05:33.149 - experiments remotely? 142 00:05:33.449 --> 00:05:35.370 - I mean, I suppose the obvious benefit is 143 00:05:35.370 --> 00:05:36.829 - that you don't have to 144 00:05:37.290 --> 00:05:39.470 - have, you know, what is a fairly 145 00:05:39.930 --> 00:05:40.430 - expensive 146 00:05:41.449 --> 00:05:42.430 - vacuum system, 147 00:05:43.209 --> 00:05:46.985 - an optical system. But, I mean, could could 148 00:05:46.985 --> 00:05:49.812 - could you talk about that? And and also 149 00:05:49.812 --> 00:05:52.992 - maybe, you know, the other benefits of using 150 00:05:52.992 --> 00:05:56.172 - the system. Yeah. So let me explain. So, 151 00:05:56.172 --> 00:05:58.999 - of course, yeah, as I said, it's a 152 00:05:58.999 --> 00:06:01.919 - kinda... Main benefit is, you know, our, 153 00:06:02.779 --> 00:06:06.319 - theoretical physicist like us can use it without, 154 00:06:07.339 --> 00:06:10.160 - I mean, building up the experiment from scratch. 155 00:06:10.459 --> 00:06:12.480 - That's the... Actually, the big benefit. 156 00:06:12.935 --> 00:06:14.615 - But I also want to say that, you 157 00:06:14.615 --> 00:06:16.154 - know, the traditional way 158 00:06:16.455 --> 00:06:18.154 - for the theoretical physicist 159 00:06:18.855 --> 00:06:21.275 - to access to the experimental facility 160 00:06:21.814 --> 00:06:23.115 - is usually to collaborate 161 00:06:23.735 --> 00:06:24.235 - with 162 00:06:24.855 --> 00:06:25.355 - experimenters. 163 00:06:25.779 --> 00:06:28.019 - Yeah? So from time time from time to 164 00:06:28.019 --> 00:06:31.479 - time, I actually had such fortunate opportunities 165 00:06:32.740 --> 00:06:34.040 - to collaborate with, 166 00:06:35.139 --> 00:06:38.439 - excellent experimenters, which I really enjoyed, actually. 167 00:06:39.044 --> 00:06:39.544 - However, 168 00:06:40.644 --> 00:06:41.544 - the initiative 169 00:06:41.925 --> 00:06:44.485 - of such collaboration is mainly taken by the 170 00:06:44.485 --> 00:06:48.185 - PI or the experimental group. So the suggestions 171 00:06:48.485 --> 00:06:51.064 - by terrorists are accepted only sometimes. 172 00:06:51.604 --> 00:06:52.410 - So that mean 173 00:06:52.810 --> 00:06:55.470 - take... So being able to take the initiative 174 00:06:56.089 --> 00:06:58.750 - of the experimental research is a big advantage 175 00:06:58.970 --> 00:07:01.529 - and a big benefit of using such kind 176 00:07:01.529 --> 00:07:04.089 - of platform. So for example, the... About twenty 177 00:07:04.089 --> 00:07:04.830 - years ago, 178 00:07:05.274 --> 00:07:07.675 - I theoretically worked on the anomaly standard or 179 00:07:07.675 --> 00:07:09.214 - the phonon or BC 180 00:07:09.754 --> 00:07:11.535 - and talked with several experimentalists 181 00:07:12.074 --> 00:07:14.095 - about possible experimental realization 182 00:07:14.555 --> 00:07:15.935 - of this interesting phenomenon. 183 00:07:16.795 --> 00:07:17.295 - Unfortunately, 184 00:07:17.675 --> 00:07:19.134 - there were no experimentalists 185 00:07:19.920 --> 00:07:22.180 - who actually conducted such experiments. 186 00:07:22.800 --> 00:07:25.920 - So twenty years later, we could observe such 187 00:07:25.920 --> 00:07:27.939 - signatures of this unknown standard 188 00:07:28.639 --> 00:07:32.500 - by using remote PC strength service, this octant. 189 00:07:33.519 --> 00:07:36.375 - So I think that this indeed demonstrates 190 00:07:36.834 --> 00:07:38.295 - the benefits of octant. 191 00:07:39.795 --> 00:07:42.375 - So, Ipe, does that mean, as a theorist, 192 00:07:42.754 --> 00:07:44.214 - you feel closer 193 00:07:44.514 --> 00:07:45.415 - to the experiment? 194 00:07:46.435 --> 00:07:48.774 - You know, maybe in the past when you 195 00:07:49.000 --> 00:07:51.339 - you you weren't actually controlling a BEC, 196 00:07:52.040 --> 00:07:53.959 - the, you know, the whole system seemed a 197 00:07:53.959 --> 00:07:56.919 - bit foreign and away from your work. But 198 00:07:56.919 --> 00:07:59.419 - now that you... You're almost hands on, 199 00:08:00.199 --> 00:08:01.720 - do do, you know, do you feel that 200 00:08:01.720 --> 00:08:04.115 - you have more insights into the physical system 201 00:08:04.115 --> 00:08:05.014 - using Octant? 202 00:08:05.634 --> 00:08:08.035 - Yeah. Of course. I mean, the real system 203 00:08:08.035 --> 00:08:09.654 - is much dirtier than the theory. 204 00:08:10.035 --> 00:08:10.535 - Right? 205 00:08:10.995 --> 00:08:12.214 - So... Yeah. 206 00:08:12.675 --> 00:08:14.354 - I mean, you have to take care of 207 00:08:14.354 --> 00:08:16.694 - the noise or, you know, some 208 00:08:17.160 --> 00:08:20.139 - calibration stuff also. So, yeah, we... 209 00:08:20.600 --> 00:08:21.180 - I mean, 210 00:08:21.800 --> 00:08:23.960 - in in that sense, we are closer to 211 00:08:23.960 --> 00:08:25.340 - the, I mean, 212 00:08:25.960 --> 00:08:26.620 - the reality. 213 00:08:28.279 --> 00:08:28.779 - So 214 00:08:29.475 --> 00:08:32.355 - that, how to say? The... But, actually, honestly, 215 00:08:32.355 --> 00:08:34.514 - I have... As I said, the... I have 216 00:08:34.514 --> 00:08:35.014 - collaborated, 217 00:08:36.274 --> 00:08:39.634 - several experiences before. In that sense, you know, 218 00:08:39.634 --> 00:08:41.875 - I already have some close... I I feel 219 00:08:41.875 --> 00:08:43.894 - that very close to this 220 00:08:44.829 --> 00:08:45.329 - system. 221 00:08:45.870 --> 00:08:49.149 - But, yeah, but, you know, the... In the 222 00:08:49.149 --> 00:08:51.490 - collaboration with the experimenters, usually, 223 00:08:51.870 --> 00:08:54.209 - experimenters take care of this kind of dirty 224 00:08:54.669 --> 00:08:55.169 - environment 225 00:08:55.709 --> 00:08:57.250 - in the experiment. So 226 00:08:57.664 --> 00:08:59.524 - we... I actually learned 227 00:08:59.904 --> 00:09:03.605 - how the... How great the syringe is actually. 228 00:09:04.304 --> 00:09:05.524 - They they are kinda... 229 00:09:06.225 --> 00:09:08.644 - They have this kind of... Yeah. Yeah. That... 230 00:09:08.865 --> 00:09:11.204 - I mean, the ability to get a very 231 00:09:11.345 --> 00:09:14.509 - clear physics. Yes. Interesting. And have you been... 232 00:09:14.509 --> 00:09:16.990 - I mean, in your experience using Octant, have 233 00:09:16.990 --> 00:09:17.809 - you been tempted 234 00:09:18.669 --> 00:09:21.790 - to maybe do some experimental work, or do 235 00:09:21.790 --> 00:09:23.970 - you think that you're always going to be 236 00:09:24.269 --> 00:09:26.245 - a theorist? I I mean, can you see 237 00:09:26.245 --> 00:09:28.644 - yourself working in a lab? I suppose you 238 00:09:28.644 --> 00:09:31.284 - don't have to, but... Yeah. To be honest, 239 00:09:31.284 --> 00:09:31.784 - I'm 240 00:09:32.164 --> 00:09:34.345 - happy to be a theorist. I mean... 241 00:09:34.884 --> 00:09:36.964 - Yeah. Yeah. I don't know. That that can 242 00:09:36.964 --> 00:09:38.804 - be the physics world quote of the week. 243 00:09:38.804 --> 00:09:40.184 - I'm happy to be a theorist. 244 00:09:43.970 --> 00:09:47.250 - Yeah. Definitely. It's, yeah. I I just think 245 00:09:47.250 --> 00:09:49.649 - that the experimenters are so great because they 246 00:09:49.649 --> 00:09:51.350 - can... Are very patient 247 00:09:51.809 --> 00:09:54.764 - to fight with those kind of... Yeah. They're... 248 00:09:54.985 --> 00:09:56.285 - I mean, that reality. 249 00:09:56.665 --> 00:09:59.065 - And and, Daichi, we've we've spoken about some 250 00:09:59.065 --> 00:10:00.125 - positive aspects 251 00:10:00.425 --> 00:10:01.165 - of doing 252 00:10:01.545 --> 00:10:02.524 - remote experiments 253 00:10:02.985 --> 00:10:03.805 - on BECs. 254 00:10:05.065 --> 00:10:06.764 - Are there any negative 255 00:10:07.500 --> 00:10:08.000 - aspects 256 00:10:08.300 --> 00:10:10.240 - to doing remote experiments? 257 00:10:11.259 --> 00:10:11.899 - One thing, 258 00:10:12.540 --> 00:10:14.480 - we have to keep in mind 259 00:10:15.019 --> 00:10:15.519 - was, 260 00:10:17.500 --> 00:10:18.960 - remote users still 261 00:10:19.394 --> 00:10:23.014 - carefully characterize the parameters of the apparatus and 262 00:10:23.875 --> 00:10:26.435 - the initial state of the BC. So for 263 00:10:26.435 --> 00:10:26.935 - example, 264 00:10:27.795 --> 00:10:29.575 - we initially assume that 265 00:10:30.195 --> 00:10:32.455 - the prepared BC is stationary. 266 00:10:33.740 --> 00:10:36.399 - But in fact, the prepared BC 267 00:10:36.779 --> 00:10:37.600 - was undergoing 268 00:10:38.139 --> 00:10:39.519 - a small dipole oscillation. 269 00:10:40.139 --> 00:10:41.120 - Yeah. This is 270 00:10:41.899 --> 00:10:42.720 - this is because, 271 00:10:44.139 --> 00:10:46.995 - BC first prepared in a cooling trap and 272 00:10:46.995 --> 00:10:49.575 - then transferred to imaging trap. 273 00:10:50.514 --> 00:10:51.495 - And the, 274 00:10:52.995 --> 00:10:55.014 - trap center... Two trap centers 275 00:10:55.634 --> 00:10:57.095 - are not perfectly aligned. 276 00:10:57.875 --> 00:10:59.975 - For this reason, we first apply, 277 00:11:00.959 --> 00:11:02.419 - linear potential to 278 00:11:03.279 --> 00:11:05.459 - to reduce this initial motion, 279 00:11:06.240 --> 00:11:07.539 - yeah, in our experiment. 280 00:11:08.079 --> 00:11:09.279 - We also found that, 281 00:11:10.799 --> 00:11:14.399 - some parameters... Some experimental parameters to lift it 282 00:11:14.399 --> 00:11:15.139 - over time. 283 00:11:15.975 --> 00:11:16.634 - For example, 284 00:11:17.414 --> 00:11:17.975 - we found, 285 00:11:18.774 --> 00:11:20.235 - the center of a trap, 286 00:11:20.695 --> 00:11:21.754 - yeah, could change, 287 00:11:22.454 --> 00:11:24.235 - from week to week. So 288 00:11:25.095 --> 00:11:25.595 - so, 289 00:11:26.134 --> 00:11:28.794 - at the beginning of each experimental periods, 290 00:11:29.259 --> 00:11:30.240 - we first measure 291 00:11:30.620 --> 00:11:31.120 - the 292 00:11:31.579 --> 00:11:35.500 - the dipoles... Yes. Affirmation dipole oscillation and estimate 293 00:11:35.500 --> 00:11:38.159 - the trap of... Trap center from, 294 00:11:39.100 --> 00:11:39.919 - from that 295 00:11:40.379 --> 00:11:41.199 - that motion. 296 00:11:41.500 --> 00:11:43.304 - Yeah. And, yeah, we correct 297 00:11:44.424 --> 00:11:46.445 - our ex... Experimental schedule, 298 00:11:47.225 --> 00:11:48.605 - yeah, from estimates, 299 00:11:50.105 --> 00:11:50.924 - top center. 300 00:11:51.464 --> 00:11:52.284 - So overall, 301 00:11:53.464 --> 00:11:55.804 - even using a remote experimental platform, 302 00:11:56.664 --> 00:11:57.245 - we still 303 00:11:59.230 --> 00:11:59.730 - carefully 304 00:12:00.590 --> 00:12:01.090 - carefully 305 00:12:01.629 --> 00:12:03.730 - characterize the experimental parameters 306 00:12:04.990 --> 00:12:06.049 - and correct for... 307 00:12:08.029 --> 00:12:11.149 - And what did the effect before the... If 308 00:12:11.149 --> 00:12:13.235 - you are carrying out the main 309 00:12:13.774 --> 00:12:14.274 - experiment. 310 00:12:14.735 --> 00:12:17.934 - I see. And and, Ipi, is that... Is 311 00:12:17.934 --> 00:12:21.154 - the problem here the fact that you're using 312 00:12:21.214 --> 00:12:22.434 - a a generic 313 00:12:23.294 --> 00:12:24.115 - Bose Einstein, 314 00:12:25.470 --> 00:12:26.690 - experimental apparatus. 315 00:12:27.389 --> 00:12:30.509 - And if if you, you know, you know, 316 00:12:30.509 --> 00:12:32.290 - let's say you were doing this experiment, 317 00:12:33.230 --> 00:12:35.169 - you know, on your own in the lab, 318 00:12:35.470 --> 00:12:38.049 - you would have designed an apparatus where this 319 00:12:38.110 --> 00:12:39.330 - back and forth motion 320 00:12:40.334 --> 00:12:42.815 - was not a problem or could be more 321 00:12:42.815 --> 00:12:44.894 - easily dealt with? I mean, I suppose my 322 00:12:44.894 --> 00:12:46.574 - question is, you know, is the issue here 323 00:12:46.574 --> 00:12:48.514 - that you... You're trying to do a specific 324 00:12:49.054 --> 00:12:52.495 - experiment on a a system? Yeah. Definitely. If 325 00:12:52.495 --> 00:12:52.995 - you, 326 00:12:53.889 --> 00:12:55.190 - I mean, if you 327 00:12:56.209 --> 00:12:59.350 - have such kind of system in your lab, 328 00:12:59.490 --> 00:13:00.629 - you could easily 329 00:13:01.009 --> 00:13:04.289 - realize that, the motion should happen because the... 330 00:13:04.289 --> 00:13:05.990 - In the... What... After 331 00:13:06.370 --> 00:13:07.965 - we recognize that the 332 00:13:08.764 --> 00:13:09.904 - the trap for cooling 333 00:13:10.524 --> 00:13:11.345 - of the BC 334 00:13:11.805 --> 00:13:13.345 - and the trap for the, 335 00:13:14.845 --> 00:13:15.665 - laser manipulation 336 00:13:16.125 --> 00:13:19.665 - seeing this, for observing the BC dynamics. 337 00:13:20.045 --> 00:13:21.965 - So those two are actually different traps. So 338 00:13:21.965 --> 00:13:23.504 - they they actually transfer 339 00:13:23.809 --> 00:13:26.230 - the BC from one trap to the another. 340 00:13:26.449 --> 00:13:28.230 - But we actually didn't know. 341 00:13:28.610 --> 00:13:31.649 - So if you transfer the BC from one 342 00:13:31.649 --> 00:13:32.709 - trap to another, 343 00:13:33.329 --> 00:13:35.409 - it's very natural that you call this type 344 00:13:35.409 --> 00:13:38.184 - of oscillation. Right? So if you build up 345 00:13:38.184 --> 00:13:40.605 - the system by yourself, you should know it. 346 00:13:42.024 --> 00:13:44.204 - Yeah. But, we didn't know because we didn't 347 00:13:44.504 --> 00:13:47.464 - build up the system by ourselves. I see. 348 00:13:47.464 --> 00:13:48.524 - Okay. Gotcha. 349 00:13:49.460 --> 00:13:50.840 - And, and Ipe, 350 00:13:51.860 --> 00:13:55.000 - in in a recent paper, you explored phonon 351 00:13:55.139 --> 00:13:55.639 - tunneling 352 00:13:56.100 --> 00:13:57.080 - in a BEC. 353 00:13:58.580 --> 00:14:00.660 - What what is phonon tunneling? And can can 354 00:14:00.660 --> 00:14:02.920 - you describe the measurements that you made? 355 00:14:03.940 --> 00:14:04.274 - Yes. 356 00:14:04.835 --> 00:14:08.215 - Let me first briefly explain the anomalous tunneling 357 00:14:08.514 --> 00:14:11.315 - of the phonon in BC, which is a 358 00:14:11.315 --> 00:14:13.254 - important protein of this, phonon 359 00:14:13.795 --> 00:14:14.295 - tunneling. 360 00:14:15.154 --> 00:14:18.299 - So in a conventional quantum tunneling, like the 361 00:14:18.299 --> 00:14:21.519 - case of, non interacting electrons or atoms, 362 00:14:22.059 --> 00:14:25.100 - when you decrease the energy of the quantum 363 00:14:25.100 --> 00:14:25.600 - particle, 364 00:14:26.299 --> 00:14:28.720 - the transmission probability actually decreases 365 00:14:29.340 --> 00:14:31.485 - and approaches zero at 366 00:14:31.964 --> 00:14:34.605 - limit of zero energy. I mean, the low 367 00:14:34.605 --> 00:14:35.584 - energy particle 368 00:14:36.204 --> 00:14:38.464 - hardly handles through a barrier. 369 00:14:39.884 --> 00:14:42.764 - By contrast, in the case of phonons in 370 00:14:42.764 --> 00:14:43.264 - BC, 371 00:14:43.804 --> 00:14:45.664 - the tendency is actually opposite. 372 00:14:46.169 --> 00:14:47.870 - I mean, when you decrease 373 00:14:48.250 --> 00:14:48.909 - the energy, 374 00:14:49.450 --> 00:14:53.789 - the transmission probability actually increases and approaches unity 375 00:14:54.169 --> 00:14:55.549 - at zero energy limit. 376 00:14:56.490 --> 00:14:58.669 - So the low energy phonons exhibit 377 00:14:59.129 --> 00:15:00.190 - almost perfect 378 00:15:00.674 --> 00:15:01.174 - tunneling. 379 00:15:01.794 --> 00:15:02.615 - That's the 380 00:15:03.235 --> 00:15:04.375 - anomalous tunneling. 381 00:15:05.475 --> 00:15:09.235 - So since this interesting phenomenon has never been 382 00:15:09.235 --> 00:15:09.735 - observed, 383 00:15:10.674 --> 00:15:12.134 - in experiments before, 384 00:15:13.049 --> 00:15:16.909 - We aim to experimentally observe it by using 385 00:15:17.129 --> 00:15:17.529 - this, 386 00:15:18.090 --> 00:15:19.389 - remote BC platform 387 00:15:20.090 --> 00:15:20.590 - octant. 388 00:15:21.370 --> 00:15:22.909 - As a specific protocol, 389 00:15:23.210 --> 00:15:26.009 - we actually first part of the BC in 390 00:15:26.009 --> 00:15:28.654 - a double trap. Double trap mean that the 391 00:15:28.654 --> 00:15:29.634 - trap plus, 392 00:15:30.415 --> 00:15:32.434 - barrier potential at the trap center. 393 00:15:33.615 --> 00:15:34.115 - So... 394 00:15:34.415 --> 00:15:37.054 - And the... This part of patient to the 395 00:15:37.054 --> 00:15:39.075 - BC actually induce the corrective 396 00:15:39.455 --> 00:15:39.955 - oscillation 397 00:15:40.495 --> 00:15:41.795 - of the BC. 398 00:15:42.550 --> 00:15:45.670 - And from the observed oscillation, we actually measure 399 00:15:45.670 --> 00:15:47.450 - this oscillation. And from the 400 00:15:47.990 --> 00:15:48.970 - observed oscillation, 401 00:15:49.590 --> 00:15:51.290 - we could extract 402 00:15:52.149 --> 00:15:52.649 - frequencies 403 00:15:53.190 --> 00:15:56.389 - of the collective oscillation modes for several values 404 00:15:56.389 --> 00:15:57.610 - of the barrier height. 405 00:15:58.115 --> 00:16:01.315 - So we find that the quality modes with 406 00:16:01.315 --> 00:16:01.815 - relatively 407 00:16:02.274 --> 00:16:03.095 - low frequencies 408 00:16:03.714 --> 00:16:05.254 - are not very much affected 409 00:16:05.794 --> 00:16:07.414 - by a high barrier. 410 00:16:08.034 --> 00:16:10.434 - This means that the potential barrier is less 411 00:16:10.434 --> 00:16:10.934 - effective 412 00:16:12.059 --> 00:16:13.919 - to lower frequency modes. 413 00:16:14.539 --> 00:16:17.579 - So this measurement captures a signal, the animal 414 00:16:17.579 --> 00:16:18.079 - standing 415 00:16:18.539 --> 00:16:19.679 - of BC phonon. 416 00:16:20.779 --> 00:16:23.259 - I see. And and are there any, 417 00:16:24.459 --> 00:16:26.559 - well, for lack of a better word, practical 418 00:16:27.554 --> 00:16:30.274 - applications of this phonon tunneling effect? I mean, 419 00:16:30.274 --> 00:16:31.735 - is it something that could be 420 00:16:32.274 --> 00:16:34.375 - exploited in quantum computation 421 00:16:34.915 --> 00:16:36.215 - or quantum sensing? 422 00:16:36.915 --> 00:16:39.394 - Or is it is it just, well, just. 423 00:16:39.394 --> 00:16:41.815 - Is it a, you know, an interesting 424 00:16:42.500 --> 00:16:44.839 - phenomenon that needs to be understood? 425 00:16:46.179 --> 00:16:48.019 - Yeah. Yeah. That's good question. But, 426 00:16:48.659 --> 00:16:50.440 - no. I mean, we are 427 00:16:50.820 --> 00:16:51.559 - not very... 428 00:16:52.500 --> 00:16:53.159 - I mean, 429 00:16:54.100 --> 00:16:55.559 - have, any immediate 430 00:16:55.940 --> 00:16:57.480 - application of this phenomenon. 431 00:16:57.785 --> 00:17:00.445 - But this but, this phenomenon is, 432 00:17:01.345 --> 00:17:02.924 - what... At least, I believe, 433 00:17:03.384 --> 00:17:04.924 - important in two sense. 434 00:17:05.464 --> 00:17:07.945 - One is that, it is related to the 435 00:17:07.945 --> 00:17:10.825 - other interesting phenomenon of the BC, which is 436 00:17:10.825 --> 00:17:11.404 - a superfluidity. 437 00:17:12.340 --> 00:17:15.059 - Well, in my PhD work, actually, we... I 438 00:17:15.059 --> 00:17:15.559 - actually, 439 00:17:16.180 --> 00:17:19.160 - showed that, you know, anomalous tunneling property 440 00:17:19.700 --> 00:17:23.000 - is closely related to this b... Superfluid property 441 00:17:23.140 --> 00:17:25.460 - or the BEC. But it's very natural that 442 00:17:25.460 --> 00:17:27.000 - in the... So, you know, original, 443 00:17:28.285 --> 00:17:31.904 - famous Landau... Lev Landau's superfluid theory, 444 00:17:32.285 --> 00:17:33.184 - quasi particle 445 00:17:33.724 --> 00:17:35.345 - is included in the phonon excitation, 446 00:17:36.205 --> 00:17:37.664 - is the key to understand 447 00:17:38.205 --> 00:17:39.424 - the superfluid property. 448 00:17:40.150 --> 00:17:43.930 - The other thing is that, recent theoretical studies, 449 00:17:43.990 --> 00:17:46.089 - not not our work, actually 450 00:17:46.630 --> 00:17:48.569 - show that this anomalous standard 451 00:17:49.029 --> 00:17:50.809 - is, some universal 452 00:17:51.190 --> 00:17:53.450 - property of some condensed matter system 453 00:17:54.150 --> 00:17:54.650 - with 454 00:17:56.775 --> 00:18:00.394 - breaking... A spontaneous symmetry breaking or continuous symmetry. 455 00:18:00.535 --> 00:18:01.755 - I mean, the... 456 00:18:02.294 --> 00:18:03.115 - Something like, 457 00:18:04.535 --> 00:18:05.755 - some magnets, 458 00:18:06.214 --> 00:18:06.714 - antiferromagnet, 459 00:18:07.095 --> 00:18:08.794 - for example, a good example, 460 00:18:09.575 --> 00:18:10.710 - also exhibit 461 00:18:11.109 --> 00:18:13.849 - this unknown standing property. So it's a physicist 462 00:18:13.909 --> 00:18:16.089 - like this type of universal property. 463 00:18:16.869 --> 00:18:17.369 - Right? 464 00:18:17.990 --> 00:18:18.809 - We understand, 465 00:18:19.589 --> 00:18:20.089 - many 466 00:18:21.269 --> 00:18:23.450 - diverse system with single concept. 467 00:18:24.069 --> 00:18:26.565 - So... Well, of course, this formal excitation in 468 00:18:26.804 --> 00:18:29.684 - BC is character... Categorized as a number of 469 00:18:29.684 --> 00:18:30.504 - calls to mode. 470 00:18:31.365 --> 00:18:34.024 - So the recent study showed that this, 471 00:18:35.204 --> 00:18:38.744 - animal standing is actually the very universal property 472 00:18:38.804 --> 00:18:40.585 - of the number of calls to mode. So, 473 00:18:40.964 --> 00:18:42.089 - you know, this is that 474 00:18:42.650 --> 00:18:44.569 - how to say. I have to say not 475 00:18:44.569 --> 00:18:45.869 - application to the, 476 00:18:46.730 --> 00:18:47.630 - quantum technology, 477 00:18:48.169 --> 00:18:50.730 - but at least it's... You know? Yeah. We 478 00:18:50.730 --> 00:18:52.029 - are... As a physicist, 479 00:18:52.329 --> 00:18:54.250 - we should be very happy to fund this, 480 00:18:54.569 --> 00:18:57.815 - very universal property of this, this, number or 481 00:18:57.815 --> 00:18:59.234 - so more. And 482 00:19:00.414 --> 00:19:01.955 - and Daichi, you're you're 483 00:19:02.335 --> 00:19:02.835 - using 484 00:19:03.455 --> 00:19:06.595 - an experiment that's thousands of miles away. 485 00:19:07.695 --> 00:19:09.775 - You're in Japan, and I think the the 486 00:19:09.775 --> 00:19:11.875 - the apparatus is in The United States. 487 00:19:12.420 --> 00:19:14.759 - You weren't involved in building, 488 00:19:16.019 --> 00:19:18.180 - the experiments, and you're not sort of in 489 00:19:18.180 --> 00:19:21.000 - the room when the experiments are done. 490 00:19:21.380 --> 00:19:23.080 - How can you be confident 491 00:19:23.619 --> 00:19:26.039 - in the sort of experimental 492 00:19:26.420 --> 00:19:28.625 - parameters and data that 493 00:19:29.005 --> 00:19:30.865 - that you're being sent back? 494 00:19:32.365 --> 00:19:33.105 - You know, 495 00:19:33.404 --> 00:19:34.865 - how how do you know that the the 496 00:19:35.005 --> 00:19:36.224 - experiment is actually, 497 00:19:37.164 --> 00:19:39.325 - proceeding in the way that you think it 498 00:19:39.325 --> 00:19:41.984 - is? Yeah. That's a nice question. So 499 00:19:42.690 --> 00:19:44.149 - in in our experiment, 500 00:19:44.849 --> 00:19:46.149 - we try to verify 501 00:19:47.890 --> 00:19:49.109 - the experimental parameters 502 00:19:49.649 --> 00:19:50.549 - by comparing, 503 00:19:51.569 --> 00:19:54.230 - measurement result with theoretical expectations. 504 00:19:55.409 --> 00:19:56.390 - Yeah. For example, 505 00:19:57.250 --> 00:19:57.909 - the most 506 00:19:58.715 --> 00:19:59.914 - direct test was, 507 00:20:01.275 --> 00:20:02.095 - actual frequency. 508 00:20:03.515 --> 00:20:04.255 - Yeah. Atoms, 509 00:20:04.875 --> 00:20:05.775 - confined in 510 00:20:06.315 --> 00:20:09.515 - hammock trap, it's a collective center of mass 511 00:20:09.515 --> 00:20:10.015 - motion. 512 00:20:10.394 --> 00:20:10.894 - Sorry. 513 00:20:11.640 --> 00:20:14.839 - The frequency of the collective center of mass 514 00:20:14.839 --> 00:20:15.339 - motion 515 00:20:15.640 --> 00:20:16.299 - should be 516 00:20:16.920 --> 00:20:19.000 - the same as the trap center... A trap 517 00:20:19.000 --> 00:20:19.500 - frequency. 518 00:20:19.880 --> 00:20:21.420 - So, we measure 519 00:20:21.960 --> 00:20:23.900 - it and obtain approximately 520 00:20:24.200 --> 00:20:25.259 - 42 hertz 521 00:20:25.625 --> 00:20:26.125 - while 522 00:20:26.424 --> 00:20:27.485 - the Octane documentation 523 00:20:27.865 --> 00:20:29.085 - specifies the trap 524 00:20:29.625 --> 00:20:31.085 - frequency as 40 hertz. 525 00:20:31.705 --> 00:20:32.205 - So, 526 00:20:32.585 --> 00:20:33.565 - they are consistent. 527 00:20:34.025 --> 00:20:35.085 - We also perform 528 00:20:35.945 --> 00:20:37.164 - less direct consistency 529 00:20:37.465 --> 00:20:38.924 - check for other parameters. 530 00:20:39.580 --> 00:20:40.400 - As an example, 531 00:20:41.900 --> 00:20:42.559 - we checked 532 00:20:43.259 --> 00:20:44.160 - the transverse, 533 00:20:44.940 --> 00:20:45.840 - trap frequency, 534 00:20:46.700 --> 00:20:48.640 - from the frequency of, 535 00:20:49.580 --> 00:20:51.434 - second lowest collective motion. 536 00:20:51.835 --> 00:20:55.295 - We theoretically calculate the frequency of this mode 537 00:20:55.355 --> 00:20:55.855 - using 538 00:20:56.795 --> 00:20:58.255 - the transverse trap frequency 539 00:20:58.795 --> 00:21:01.134 - specified in the octant... Octant documentation, 540 00:21:01.755 --> 00:21:04.894 - and the calculated value was close to the 541 00:21:05.035 --> 00:21:05.940 - measured value. 542 00:21:06.819 --> 00:21:08.019 - So, yeah, we just, 543 00:21:08.500 --> 00:21:10.359 - did... You see, these are consistent. 544 00:21:10.819 --> 00:21:13.399 - Yeah. We performed as a consistency check, 545 00:21:14.740 --> 00:21:15.480 - as well, 546 00:21:15.859 --> 00:21:17.559 - for the parameters as well. 547 00:21:18.855 --> 00:21:20.875 - Overall, the quantity we 548 00:21:21.174 --> 00:21:21.994 - could check 549 00:21:23.255 --> 00:21:23.914 - were consistent, 550 00:21:25.654 --> 00:21:26.474 - with ex... 551 00:21:27.015 --> 00:21:29.994 - Doing experimental result with the theoretical expectations. 552 00:21:30.694 --> 00:21:32.474 - So this gave us 553 00:21:33.089 --> 00:21:35.669 - reasonable confidence in the experimental parameters 554 00:21:36.210 --> 00:21:38.690 - and data. Great. Well, it it sounds like 555 00:21:38.690 --> 00:21:40.390 - both of you are are happy 556 00:21:40.929 --> 00:21:41.410 - with, 557 00:21:42.130 --> 00:21:43.429 - with using Octant. 558 00:21:44.769 --> 00:21:47.089 - Are you are are you currently using the 559 00:21:47.089 --> 00:21:47.589 - system 560 00:21:47.934 --> 00:21:48.674 - to do, 561 00:21:50.174 --> 00:21:52.355 - cloud based BEC experiments, 562 00:21:52.894 --> 00:21:55.295 - IPE? Or do you have any plan for 563 00:21:55.295 --> 00:21:55.875 - the future? 564 00:21:56.734 --> 00:21:58.914 - Thank you for asking, actually. Currently, 565 00:21:59.455 --> 00:22:01.634 - we are not doing experiments on 566 00:22:02.000 --> 00:22:05.440 - Auckland platform just because Auckland has not been 567 00:22:05.440 --> 00:22:05.940 - open 568 00:22:06.240 --> 00:22:07.059 - to the public 569 00:22:07.680 --> 00:22:10.660 - since the late two thousand twenty four. 570 00:22:11.440 --> 00:22:14.259 - Well, for... They say it's for some upgrades. 571 00:22:15.875 --> 00:22:18.194 - So, however, yes, we have, 572 00:22:18.595 --> 00:22:20.115 - next brands of, 573 00:22:20.755 --> 00:22:22.375 - utilizing the for 574 00:22:22.914 --> 00:22:23.494 - the future. 575 00:22:24.355 --> 00:22:26.355 - But why... I cannot tell you too much 576 00:22:26.355 --> 00:22:27.734 - detail at this moment. 577 00:22:28.410 --> 00:22:31.630 - We have designed some of the future experiments 578 00:22:32.090 --> 00:22:35.289 - and made some, technical calculation for them. Yeah. 579 00:22:35.289 --> 00:22:37.049 - So we are kinda looking forward to the 580 00:22:37.049 --> 00:22:37.950 - next opening 581 00:22:38.570 --> 00:22:39.710 - of the octant. 582 00:22:42.164 --> 00:22:44.605 - Well, that's great. I hope, yeah. I I 583 00:22:44.605 --> 00:22:46.424 - I wish both of you luck in, 584 00:22:47.365 --> 00:22:49.684 - in in doing those experiments. And I'm guessing 585 00:22:49.684 --> 00:22:52.585 - you're you're probably very busy with your theory 586 00:22:52.804 --> 00:22:54.230 - work at the moment. 587 00:22:54.609 --> 00:22:56.450 - So it's not like you're you're sitting around 588 00:22:56.450 --> 00:22:57.509 - waiting for Octant 589 00:22:57.809 --> 00:23:00.130 - to come back online. But, I mean, it 590 00:23:00.130 --> 00:23:02.690 - sounds like you you you, you know, your 591 00:23:02.690 --> 00:23:04.289 - use of it was a was a great 592 00:23:04.289 --> 00:23:05.250 - success, and, 593 00:23:06.065 --> 00:23:07.744 - that they'd be very keen to get you 594 00:23:07.744 --> 00:23:08.244 - back 595 00:23:08.545 --> 00:23:09.684 - onto the system. 596 00:23:10.304 --> 00:23:12.545 - Daichi and Ipe, thank you so much for 597 00:23:12.545 --> 00:23:13.765 - coming on to the podcast 598 00:23:14.304 --> 00:23:16.964 - and talking to us about how you've used 599 00:23:17.265 --> 00:23:18.404 - a remote controlled 600 00:23:19.029 --> 00:23:20.410 - Bose Einstein condensate. 601 00:23:21.990 --> 00:23:24.390 - Yeah. Hamish, thank you very much. Yeah. Thank 602 00:23:24.390 --> 00:23:25.289 - you very much. 603 00:23:32.325 --> 00:23:35.704 - That was Ippei Danchita and Daichi Kagemihara 604 00:23:36.565 --> 00:23:38.265 - talking about their experience 605 00:23:38.644 --> 00:23:42.484 - of studying quantum tunneling while being thousands of 606 00:23:42.484 --> 00:23:44.424 - kilometers from the experimental 607 00:23:44.884 --> 00:23:45.384 - apparatus. 608 00:23:46.490 --> 00:23:48.490 - Thanks to both of them for joining me 609 00:23:48.490 --> 00:23:48.990 - today. 610 00:23:49.930 --> 00:23:51.710 - Their paper is called observation 611 00:23:52.090 --> 00:23:54.670 - of the influence of anomalous tunneling 612 00:23:55.130 --> 00:23:55.950 - on collective 613 00:23:56.410 --> 00:23:56.910 - excitations 614 00:23:57.850 --> 00:23:58.910 - via a cloud 615 00:23:59.210 --> 00:23:59.710 - experiment 616 00:24:00.090 --> 00:24:00.590 - platform 617 00:24:01.315 --> 00:24:03.095 - for Bose Einstein condensates, 618 00:24:03.955 --> 00:24:05.815 - and it's published in communications 619 00:24:06.275 --> 00:24:06.775 - physics. 620 00:24:07.555 --> 00:24:09.875 - I'll put a link to the paper in 621 00:24:09.875 --> 00:24:11.174 - the podcast notes. 622 00:24:11.795 --> 00:24:14.295 - If you enjoyed listening to today's podcast, 623 00:24:14.680 --> 00:24:17.500 - you'll find plenty more episodes to explore 624 00:24:17.880 --> 00:24:21.900 - at physicsworld.com/podcasts. 625 00:24:22.680 --> 00:24:26.119 - I'm Hamish Johnston, and our producer is Fred 626 00:24:26.119 --> 00:24:26.619 - Iles. 627 00:24:27.075 --> 00:24:29.794 - The music in our podcast is called one 628 00:24:29.794 --> 00:24:30.694 - three seven, 629 00:24:30.994 --> 00:24:33.714 - and it was composed and performed by the 630 00:24:33.714 --> 00:24:34.214 - physicist 631 00:24:34.595 --> 00:24:35.654 - Philip Moriarty. 632 00:24:36.595 --> 00:24:38.534 - We'll be back again next week. 633 00:24:38.835 --> 00:24:39.894 - Thanks for listening.