WEBVTT

1
00:00:01.480 --> 00:00:05.599
<v Speaker 1>Welcome to the quart Side. Quantum Physics podcast, an exploration

2
00:00:05.679 --> 00:00:10.880
<v Speaker 1>of the fundamental structure of reality where quantum laws govern matter, energy,

3
00:00:11.199 --> 00:00:16.239
<v Speaker 1>and information. Here, uncertainty is a feature, not a flaw,

4
00:00:16.719 --> 00:00:19.239
<v Speaker 1>and understanding begins at the smallest scales.

5
00:00:27.640 --> 00:00:30.079
<v Speaker 2>You know, when you think about the microscopic world, it's

6
00:00:30.120 --> 00:00:34.479
<v Speaker 2>easy to imagine it as this totally chaotic place, just

7
00:00:34.520 --> 00:00:37.359
<v Speaker 2>a bunch of particles bumping into each other randomly.

8
00:00:37.159 --> 00:00:38.560
<v Speaker 3>Right, just sort of microscopic soup.

9
00:00:38.640 --> 00:00:42.600
<v Speaker 2>Yeah, exactly, But there's actually an absolute dictator that governs

10
00:00:42.640 --> 00:00:47.159
<v Speaker 2>how every single particle behaves. And it's not gravity, and

11
00:00:47.840 --> 00:00:49.560
<v Speaker 2>it's not some mystical force.

12
00:00:49.600 --> 00:00:52.079
<v Speaker 3>Oh, it's symmetry, which I mean is a word we

13
00:00:52.159 --> 00:00:54.759
<v Speaker 3>use all the time in everyday life, but in physics

14
00:00:54.759 --> 00:00:56.039
<v Speaker 3>it's an entirely different beast.

15
00:00:56.320 --> 00:00:58.439
<v Speaker 2>Yeah, because when you look at the atomic structure of

16
00:00:58.439 --> 00:01:03.000
<v Speaker 2>a crystal, symmetry doesn't just describe, you know, how pretty

17
00:01:03.119 --> 00:01:05.519
<v Speaker 2>or repeating the pattern is. It acts as a strict

18
00:01:05.599 --> 00:01:06.760
<v Speaker 2>mathematical rule.

19
00:01:06.519 --> 00:01:10.120
<v Speaker 3>Book, a very rigid rule book. It dictates exactly how

20
00:01:10.159 --> 00:01:13.280
<v Speaker 3>atoms are arranged and more importantly, how they are allowed to.

21
00:01:13.239 --> 00:01:16.879
<v Speaker 2>Move, and it specifically hands out absolute do not interact

22
00:01:16.959 --> 00:01:20.799
<v Speaker 2>orders between certain vibrations, Like, if two vibrations don't share

23
00:01:20.799 --> 00:01:24.079
<v Speaker 2>the right symmetry, they are categorically forbidden from mixing.

24
00:01:24.280 --> 00:01:27.359
<v Speaker 3>They cannot mix. It acts as an impenetrable wall. I mean,

25
00:01:27.560 --> 00:01:30.359
<v Speaker 3>in solid state physics we rely heavily on those exact

26
00:01:30.400 --> 00:01:33.280
<v Speaker 3>selection rules. They give order to the chaos of billions

27
00:01:33.319 --> 00:01:37.000
<v Speaker 3>of atoms jiggling around. Right, If symmetry says two quantum

28
00:01:37.040 --> 00:01:40.239
<v Speaker 3>states can't couple, they don't. We treat that as a

29
00:01:40.280 --> 00:01:42.000
<v Speaker 3>fundamental constant of the material.

30
00:01:42.120 --> 00:01:45.280
<v Speaker 2>But today we are looking at a breakthrough that actually

31
00:01:45.280 --> 00:01:48.760
<v Speaker 2>found a loophole in that exact rule book. We're going

32
00:01:48.799 --> 00:01:54.000
<v Speaker 2>to explore how a truly bizarre quantum state actively rewrites

33
00:01:54.120 --> 00:01:56.799
<v Speaker 2>the rigid rules of symmetry in a crystal.

34
00:01:56.959 --> 00:01:59.719
<v Speaker 3>Yeah, and this isn't just a theoretical curiosity either. It

35
00:01:59.760 --> 00:02:03.359
<v Speaker 3>can completely changes the way we can manipulate quantum.

36
00:02:02.959 --> 00:02:06.959
<v Speaker 2>Materials because understanding this loophole is basically a gateway to

37
00:02:07.040 --> 00:02:10.520
<v Speaker 2>the future of quantum technology. So for you listening, this

38
00:02:10.560 --> 00:02:13.919
<v Speaker 2>isn't just abstract math. This is the physical foundation for

39
00:02:14.120 --> 00:02:15.759
<v Speaker 2>the next generation of tech exactly.

40
00:02:15.840 --> 00:02:19.280
<v Speaker 3>But to understand how a rule that fundamental gives been

41
00:02:19.319 --> 00:02:20.919
<v Speaker 3>we first have to look at the material where this

42
00:02:20.960 --> 00:02:21.919
<v Speaker 3>actually happens.

43
00:02:21.680 --> 00:02:23.199
<v Speaker 2>Right, we have to meet the rule breaker.

44
00:02:23.400 --> 00:02:26.599
<v Speaker 3>Yes, we're dealing with a specific type of layered crystal,

45
00:02:27.360 --> 00:02:30.360
<v Speaker 3>a transition metal to calcagenide.

46
00:02:29.479 --> 00:02:31.240
<v Speaker 2>Which is quite the mouthful, it is.

47
00:02:31.319 --> 00:02:34.840
<v Speaker 3>Yeah, yeah, But basically inside this material, the ions and

48
00:02:34.840 --> 00:02:37.919
<v Speaker 3>electrons don't just sit in a standard boring grid. They

49
00:02:37.960 --> 00:02:39.840
<v Speaker 3>spontaneously rearrange.

50
00:02:39.319 --> 00:02:40.919
<v Speaker 2>Themselves, okay, rearrange how.

51
00:02:41.039 --> 00:02:45.919
<v Speaker 3>Into a static wavelike pattern across the crystal lattice. Physicists

52
00:02:45.960 --> 00:02:47.960
<v Speaker 3>call this a charge density wave.

53
00:02:47.840 --> 00:02:52.520
<v Speaker 2>A charge density way. So instead of electrons just zipping

54
00:02:52.520 --> 00:02:55.599
<v Speaker 2>around freely like they do, and say, a normal copper

55
00:02:55.639 --> 00:02:58.199
<v Speaker 2>wire in your house, right, a normal conductor, right, they're

56
00:02:58.280 --> 00:03:02.000
<v Speaker 2>bunching up in a periodic pattern like ripples frozen on

57
00:03:02.080 --> 00:03:02.520
<v Speaker 2>a pond.

58
00:03:02.680 --> 00:03:04.599
<v Speaker 3>That's actually a really good way to picture it, for

59
00:03:04.639 --> 00:03:07.400
<v Speaker 3>a frozen ripples. And the specific way they bunch up

60
00:03:07.400 --> 00:03:11.639
<v Speaker 3>in this material is fascinating. The distortion causes the atoms

61
00:03:11.639 --> 00:03:17.479
<v Speaker 3>to shift slightly, forming this intricate microscopic tiling of clusters.

62
00:03:17.560 --> 00:03:20.280
<v Speaker 2>And these clusters have a very specific shape, right they do.

63
00:03:20.439 --> 00:03:23.000
<v Speaker 3>They look remarkably like the Star of David, like.

64
00:03:23.000 --> 00:03:26.080
<v Speaker 2>Literally a six pointed star. Geometry just down at the

65
00:03:26.120 --> 00:03:26.800
<v Speaker 2>atomic level.

66
00:03:26.879 --> 00:03:30.000
<v Speaker 3>Yes, exactly, And here is where it gets highly exotic.

67
00:03:30.639 --> 00:03:34.159
<v Speaker 3>These Star of David clusters don't just form symmetrically. They

68
00:03:34.199 --> 00:03:36.879
<v Speaker 3>have a built in twist and twist, yeah, they can

69
00:03:36.919 --> 00:03:40.240
<v Speaker 3>lock into one of two distinct orientations, effectively giving the

70
00:03:40.319 --> 00:03:41.639
<v Speaker 3>crystal a handedness.

71
00:03:41.719 --> 00:03:44.840
<v Speaker 2>Okay, wait, handedness like left and right hands precisely.

72
00:03:45.039 --> 00:03:47.120
<v Speaker 3>Yeah, similar to how your left hand in right hand

73
00:03:47.159 --> 00:03:50.520
<v Speaker 3>or mirror images. But you can't perfectly superimpose them on

74
00:03:50.560 --> 00:03:51.240
<v Speaker 3>top of each other.

75
00:03:51.360 --> 00:03:52.879
<v Speaker 2>Right if you put a right handed glove on your

76
00:03:52.960 --> 00:03:55.000
<v Speaker 2>left hand, it doesn't fit exactly.

77
00:03:55.759 --> 00:03:59.520
<v Speaker 3>In physics, we call this planar chirality. When a crystal

78
00:03:59.599 --> 00:04:03.439
<v Speaker 3>establish is this handed pattern, it enters a quantum state

79
00:04:03.759 --> 00:04:05.479
<v Speaker 3>known as ferro axial order.

80
00:04:06.000 --> 00:04:08.680
<v Speaker 2>Okay, ferro axial order. Let me make sure I'm visualizing

81
00:04:08.719 --> 00:04:12.639
<v Speaker 2>this right for you guys listening. I'm picturing a microscopic

82
00:04:12.800 --> 00:04:16.279
<v Speaker 2>floor tile pattern made of the Star of David shapes.

83
00:04:16.839 --> 00:04:19.600
<v Speaker 2>But half the floor might be tiled with like left

84
00:04:19.600 --> 00:04:21.879
<v Speaker 2>handed stars and the other half is tiled with right

85
00:04:21.920 --> 00:04:22.639
<v Speaker 2>handed stars.

86
00:04:22.839 --> 00:04:24.920
<v Speaker 3>You're definitely on the right track with that. But the

87
00:04:25.000 --> 00:04:27.759
<v Speaker 3>challenge with this specific floor pattern is that you can

88
00:04:27.879 --> 00:04:30.439
<v Speaker 3>actually see it with our standard scientific tool.

89
00:04:30.519 --> 00:04:32.680
<v Speaker 2>Wait, why not. If it's a physical distortion of the

90
00:04:32.759 --> 00:04:34.879
<v Speaker 2>electrons and the atoms. Shouldn't we be able to just

91
00:04:34.920 --> 00:04:38.079
<v Speaker 2>bounce X rays off it or measure its electric field.

92
00:04:38.319 --> 00:04:42.519
<v Speaker 3>You would think so, but fur axial order is incredibly elusive.

93
00:04:42.959 --> 00:04:45.759
<v Speaker 3>I mean, think about a standard ferromagnet, like a magnet

94
00:04:45.800 --> 00:04:49.199
<v Speaker 3>on your fridge. It has a net magnetic moment. All

95
00:04:49.240 --> 00:04:52.079
<v Speaker 3>the little atomic compass needles point the same way. So

96
00:04:52.160 --> 00:04:54.920
<v Speaker 3>if you bring a magnetic field near it, it reacts.

97
00:04:55.040 --> 00:04:56.720
<v Speaker 3>You can measure that reaction easily.

98
00:04:56.800 --> 00:04:58.879
<v Speaker 2>Yeah, it snaps right onto the fridge.

99
00:04:58.560 --> 00:05:01.879
<v Speaker 3>Right, But this for axial order doesn't have a net

100
00:05:01.920 --> 00:05:05.399
<v Speaker 3>electrical dipole, and it doesn't have a net magnetic.

101
00:05:04.959 --> 00:05:08.040
<v Speaker 2>Moment because of the way the stars are arranged.

102
00:05:07.879 --> 00:05:11.639
<v Speaker 3>Exactly, because of how the symmetry is broken, those classical

103
00:05:11.639 --> 00:05:13.600
<v Speaker 3>properties perfectly cancel each other out.

104
00:05:13.720 --> 00:05:16.279
<v Speaker 2>Oh wow, so it doesn't react to magnets and it

105
00:05:16.279 --> 00:05:18.040
<v Speaker 2>doesn't react to electric fields at all.

106
00:05:18.160 --> 00:05:22.480
<v Speaker 3>Nope. Standard optical experiments and conventional probes pass right through it.

107
00:05:23.160 --> 00:05:26.439
<v Speaker 3>They are completely blind to whether the domains are left

108
00:05:26.439 --> 00:05:27.560
<v Speaker 3>handed or right handed.

109
00:05:27.800 --> 00:05:32.360
<v Speaker 2>It's basically a ghost to our standard scientific metal detector.

110
00:05:32.439 --> 00:05:33.199
<v Speaker 3>That's a great way to put it.

111
00:05:33.240 --> 00:05:35.480
<v Speaker 2>Yeah, but wait, if it's effectively a ghost, how do

112
00:05:35.519 --> 00:05:37.639
<v Speaker 2>we even know it's there? Are we just guessing that

113
00:05:37.680 --> 00:05:41.079
<v Speaker 2>these left and right handed stars exist in the crystal?

114
00:05:41.199 --> 00:05:44.519
<v Speaker 3>Oh, we're not guessing. We know they're there because the

115
00:05:44.560 --> 00:05:49.160
<v Speaker 3>pattern isn't a frozen, rigid thing. It's a highly coordinated

116
00:05:49.279 --> 00:05:50.879
<v Speaker 3>dynamic structure.

117
00:05:50.519 --> 00:05:51.279
<v Speaker 2>Meaning it moves.

118
00:05:51.800 --> 00:05:56.079
<v Speaker 3>Yes, those Star of David clusters vibrate, but it's not

119
00:05:56.120 --> 00:05:59.120
<v Speaker 3>just a random jiggle from heat. They move together in

120
00:05:59.160 --> 00:06:01.279
<v Speaker 3>a collective synchronized vibration.

121
00:06:01.319 --> 00:06:05.160
<v Speaker 2>Look at microscopic dance routine sort of, but more like breathing.

122
00:06:05.439 --> 00:06:09.199
<v Speaker 3>The entire wave pattern periodically expands and contracts in unison.

123
00:06:09.800 --> 00:06:12.879
<v Speaker 3>It modulates its own strength. Oh. Interesting, and physicists have

124
00:06:12.920 --> 00:06:16.360
<v Speaker 3>a highly specific term for this collective breathing motion of

125
00:06:16.399 --> 00:06:19.079
<v Speaker 3>a charged density wave. They call it an amplitude on.

126
00:06:19.279 --> 00:06:22.360
<v Speaker 2>An amplitude on. Honestly, it sounds like a giant robot

127
00:06:22.360 --> 00:06:23.560
<v Speaker 2>from an old sci fi movie.

128
00:06:23.600 --> 00:06:25.800
<v Speaker 3>It does sound like a transformer or something, but.

129
00:06:25.839 --> 00:06:28.920
<v Speaker 2>It's really just the amplitude of this electron wave pulsing

130
00:06:28.959 --> 00:06:29.920
<v Speaker 2>in and out right.

131
00:06:29.920 --> 00:06:33.480
<v Speaker 3>It's the amplitude mode. Now Here's where the central mystery

132
00:06:33.480 --> 00:06:36.800
<v Speaker 3>of this whole research comes into play. Inside this crystal

133
00:06:36.839 --> 00:06:40.920
<v Speaker 3>you have this highly specialized amplitude on breathing away, right, Yeah,

134
00:06:40.959 --> 00:06:44.480
<v Speaker 3>but the crystal also has ordinary vibrations, just the regular

135
00:06:44.600 --> 00:06:47.600
<v Speaker 3>lattice of atoms jiggling back and forth due to thermal energy.

136
00:06:47.959 --> 00:06:50.160
<v Speaker 3>Those regular vibrations are called phonons.

137
00:06:50.360 --> 00:06:52.839
<v Speaker 2>Okay, So you have the amplitude and breathing and the

138
00:06:52.879 --> 00:06:57.199
<v Speaker 2>phonons jiggling. And because they're in the exact same crystal,

139
00:06:57.680 --> 00:07:01.439
<v Speaker 2>occupying the exact same physical space, they must be bumping

140
00:07:01.480 --> 00:07:03.680
<v Speaker 2>into each other, right, I mean they're literally sharing the

141
00:07:03.720 --> 00:07:04.519
<v Speaker 2>same atoms.

142
00:07:04.600 --> 00:07:07.560
<v Speaker 3>You would intuitively think so. Remember the absolute dictator we

143
00:07:07.600 --> 00:07:11.600
<v Speaker 3>talked about earlier. Symmetry, Yeah, the rule book. Yes, the

144
00:07:11.639 --> 00:07:16.279
<v Speaker 3>amplitude has a very specific symmetry profile and the ordinary

145
00:07:16.360 --> 00:07:21.040
<v Speaker 3>phonons have a completely different symmetry profile. Mathematically, their wave

146
00:07:21.079 --> 00:07:22.600
<v Speaker 3>functions are orthogonal.

147
00:07:22.920 --> 00:07:25.600
<v Speaker 2>Orthogonal, meaning they cross perfectly in a way that creates

148
00:07:25.680 --> 00:07:27.839
<v Speaker 2>absolutely zero interaction.

149
00:07:27.600 --> 00:07:31.399
<v Speaker 3>Exactly zero. It is a cosmic soundproof wall. Even though

150
00:07:31.399 --> 00:07:33.959
<v Speaker 3>they are happening in the exact same material. The rules

151
00:07:33.959 --> 00:07:38.720
<v Speaker 3>of quantum mechanics dictate that these two distinct vibrations cannot mix, couple,

152
00:07:38.879 --> 00:07:40.360
<v Speaker 3>or exchange energy at all.

153
00:07:40.439 --> 00:07:43.920
<v Speaker 2>That is wild. The amplitude and essentially doesn't know the

154
00:07:44.040 --> 00:07:47.079
<v Speaker 2>ordinary vibrations exist. They're sharing the same dance floor, but

155
00:07:47.120 --> 00:07:48.759
<v Speaker 2>completely ignoring each other's music.

156
00:07:49.040 --> 00:07:50.759
<v Speaker 3>That's exactly what's happening, Okay.

157
00:07:50.759 --> 00:07:53.439
<v Speaker 2>But to even test if that soundproof wall holds up,

158
00:07:53.639 --> 00:07:55.600
<v Speaker 2>the researchers had to be able to listen to the crystal.

159
00:07:56.240 --> 00:07:59.199
<v Speaker 2>If electricity and magnetism are off the table, what's left?

160
00:07:59.759 --> 00:08:01.759
<v Speaker 2>How do you probe an invisible ghost?

161
00:08:02.079 --> 00:08:05.360
<v Speaker 3>Well you had to get incredibly creative with light. Researchers

162
00:08:05.399 --> 00:08:08.519
<v Speaker 3>at UT Austin and the Max Planck Institute realized they

163
00:08:08.560 --> 00:08:11.720
<v Speaker 3>couldn't just use standard linear light. They had to use

164
00:08:11.759 --> 00:08:15.480
<v Speaker 3>a specialized technique called holicity resolved ram and scattering.

165
00:08:15.639 --> 00:08:19.399
<v Speaker 2>Okay, holicity resolved, break down the mechanism there, what is

166
00:08:19.439 --> 00:08:20.680
<v Speaker 2>the light actually doing?

167
00:08:20.920 --> 00:08:24.680
<v Speaker 3>So they hit the crystal with circularly polarized light. Imagine

168
00:08:24.680 --> 00:08:26.839
<v Speaker 3>the electric field of the light wave not just waving

169
00:08:26.920 --> 00:08:30.600
<v Speaker 3>up and down, but physically rotating as it travels through space.

170
00:08:30.439 --> 00:08:32.360
<v Speaker 2>Like tracing out a corkscrew pattern.

171
00:08:32.440 --> 00:08:34.320
<v Speaker 3>Yes, exactly like a quarkscrew.

172
00:08:34.399 --> 00:08:37.440
<v Speaker 2>So the light itself has a handedness. It's twisting either

173
00:08:37.480 --> 00:08:38.960
<v Speaker 2>clockwise or counterclockwise.

174
00:08:39.039 --> 00:08:42.480
<v Speaker 3>Precisely it carries angular momentum. Yeah, Now, when this twisting

175
00:08:42.559 --> 00:08:45.879
<v Speaker 3>light hits a chiral structure, a structure that also has handedness,

176
00:08:46.120 --> 00:08:49.000
<v Speaker 3>like our star of David flore, the absorption and scattering

177
00:08:49.000 --> 00:08:50.720
<v Speaker 3>of that light won't be symmetric.

178
00:08:51.159 --> 00:08:53.000
<v Speaker 2>Ugh, I think I see where this is going. It's

179
00:08:53.080 --> 00:08:56.159
<v Speaker 2>like trying to drive or right handed screw into a

180
00:08:56.159 --> 00:08:56.840
<v Speaker 2>piece of wood.

181
00:08:56.960 --> 00:08:58.120
<v Speaker 3>Okay, I like that right.

182
00:08:58.159 --> 00:09:01.080
<v Speaker 2>If I spin my screwdriver to the right, matching the

183
00:09:01.120 --> 00:09:03.919
<v Speaker 2>thread of the screw, it catches, It bites into the wood,

184
00:09:03.960 --> 00:09:06.639
<v Speaker 2>and I get a really strong reaction. But if I

185
00:09:06.720 --> 00:09:08.720
<v Speaker 2>take that same right handed screw and I spin my

186
00:09:08.720 --> 00:09:12.159
<v Speaker 2>screwdriver to the left, it just slips. It doesn't couple

187
00:09:12.200 --> 00:09:12.559
<v Speaker 2>at all.

188
00:09:12.879 --> 00:09:17.480
<v Speaker 3>That is a highly accurate mechanical analogy in the crystal.

189
00:09:17.600 --> 00:09:20.519
<v Speaker 3>When the graduate student running these experiments shoind you paying

190
00:09:21.120 --> 00:09:24.000
<v Speaker 3>matched the twisting direction of the light to the handedness

191
00:09:24.039 --> 00:09:27.759
<v Speaker 3>of the feroxial domain, they saw a massive peak in

192
00:09:27.799 --> 00:09:30.720
<v Speaker 3>the scattered light intensity. Wow. But when they hit that

193
00:09:30.799 --> 00:09:34.200
<v Speaker 3>same exact spot with light twisting the opposite direction, the

194
00:09:34.279 --> 00:09:36.159
<v Speaker 3>response was incredibly.

195
00:09:35.600 --> 00:09:38.159
<v Speaker 2>Weak because it just slipped. The light didn't catch the

196
00:09:38.159 --> 00:09:39.279
<v Speaker 2>symmetry of the crystal.

197
00:09:39.440 --> 00:09:43.759
<v Speaker 3>Right. By measuring that difference, the intensity imbalance between the

198
00:09:43.840 --> 00:09:46.879
<v Speaker 3>left handed and right handed light responses. They could finally

199
00:09:46.919 --> 00:09:50.679
<v Speaker 3>map out the invisible They could clearly see the microscopic

200
00:09:50.720 --> 00:09:51.879
<v Speaker 3>handedness of the crystal.

201
00:09:52.159 --> 00:09:55.200
<v Speaker 2>That is such an elegant solution. You bypass the fact

202
00:09:55.240 --> 00:09:58.440
<v Speaker 2>that it ignores magnets by literally just matching its physical

203
00:09:58.480 --> 00:10:00.639
<v Speaker 2>twist with like op tweezer.

204
00:10:00.759 --> 00:10:02.600
<v Speaker 3>It's brilliant experimental physics.

205
00:10:02.679 --> 00:10:04.600
<v Speaker 2>Okay, so now they can finally see the ghosts. They

206
00:10:04.600 --> 00:10:08.080
<v Speaker 2>map out the left and right handed domains. Where does

207
00:10:08.120 --> 00:10:11.080
<v Speaker 2>the broken roll book come in? Where does symmetry fail?

208
00:10:11.600 --> 00:10:14.399
<v Speaker 3>Well? Once they could see the pattern, they wanted to

209
00:10:14.440 --> 00:10:17.399
<v Speaker 3>see how it behaved under different conditions, So they started

210
00:10:17.440 --> 00:10:19.519
<v Speaker 3>carefully tuning the temperature of the crystal.

211
00:10:19.919 --> 00:10:23.360
<v Speaker 2>Why temperature does heating it up just make everything vibrate faster?

212
00:10:23.799 --> 00:10:27.120
<v Speaker 3>Actually, in this specific case, it does something totally counterintuitive.

213
00:10:27.480 --> 00:10:29.919
<v Speaker 3>As you heat this material up, you bring it closer

214
00:10:29.919 --> 00:10:34.000
<v Speaker 3>to the temperature where the charge density wave phase completely melts.

215
00:10:33.679 --> 00:10:35.559
<v Speaker 2>Away, like ice turning to water.

216
00:10:36.279 --> 00:10:38.840
<v Speaker 3>Kind of yeah. And as it gets closer to melting,

217
00:10:39.440 --> 00:10:43.000
<v Speaker 3>the restoring force of the wave weakens. Because the force

218
00:10:43.080 --> 00:10:47.120
<v Speaker 3>is weaker, the frequency of the amplitudin's breathing actually slows down.

219
00:10:47.200 --> 00:10:48.200
<v Speaker 3>Its energy drops.

220
00:10:48.639 --> 00:10:52.360
<v Speaker 2>Oh, that is fascinating. So by turning a temperature dial

221
00:10:52.519 --> 00:10:55.840
<v Speaker 2>on the outside of the sample, you are actively tuning

222
00:10:56.039 --> 00:11:00.279
<v Speaker 2>the internal frequency of this specific quantum dance routine. You're

223
00:11:00.320 --> 00:11:02.120
<v Speaker 2>sweeping it through different energy levels.

224
00:11:02.200 --> 00:11:06.639
<v Speaker 3>Yes, you are tuning the amplitude on. Now, remember those

225
00:11:06.759 --> 00:11:10.840
<v Speaker 3>ordinary lattice vibrations, the phonons.

226
00:11:10.399 --> 00:11:12.919
<v Speaker 2>The ones that the amplitude on is strictly forbidden from

227
00:11:12.960 --> 00:11:13.519
<v Speaker 2>interacting with.

228
00:11:13.759 --> 00:11:17.600
<v Speaker 3>Right, Well, their frequencies stay relatively constant as the temperature changes.

229
00:11:17.759 --> 00:11:20.120
<v Speaker 2>Wait, so if the normal vibrations are sitting still at

230
00:11:20.200 --> 00:11:23.120
<v Speaker 2>let's say fifty terror hurts, and you are sweeping the

231
00:11:23.159 --> 00:11:25.960
<v Speaker 2>amplitude ons frequency down from one hundred terror hurts, that's

232
00:11:25.960 --> 00:11:28.360
<v Speaker 2>going to cross. Eventually, their frequencies are going to cross.

233
00:11:28.360 --> 00:11:31.759
<v Speaker 3>Perfectly they are, And that is exactly where Francesco Barentani

234
00:11:32.000 --> 00:11:34.879
<v Speaker 3>and the rest of the research team made their massive observation.

235
00:11:35.480 --> 00:11:38.559
<v Speaker 3>As they tune the temperature, they monitor that specific light

236
00:11:38.639 --> 00:11:40.440
<v Speaker 3>intensity imbalance we talked about.

237
00:11:40.200 --> 00:11:41.960
<v Speaker 2>Earlier, the screw catching or slipping.

238
00:11:42.159 --> 00:11:45.440
<v Speaker 3>Exactly. They found that the chiral signal the imbalance spike

239
00:11:45.519 --> 00:11:48.519
<v Speaker 3>to its absolute maximum precisely when the energy of the

240
00:11:48.559 --> 00:11:51.919
<v Speaker 3>amplitude on perfectly matched the energy of one of those

241
00:11:52.000 --> 00:11:53.000
<v Speaker 3>ordinary phonons.

242
00:11:53.279 --> 00:11:55.879
<v Speaker 2>Let's pause right there, because this feels like the absolute

243
00:11:55.879 --> 00:12:00.120
<v Speaker 2>core of the breakthrough symmetry says they cannot interact, But

244
00:12:00.159 --> 00:12:03.399
<v Speaker 2>you're telling me that when their frequencies match perfectly, they do.

245
00:12:03.480 --> 00:12:06.960
<v Speaker 3>They do more than interact, They profoundly influence one another.

246
00:12:07.480 --> 00:12:12.399
<v Speaker 3>Theorist emil Vinas Bostrom describes what happens as a resonant bridge.

247
00:12:12.279 --> 00:12:13.159
<v Speaker 2>A resonant bridge.

248
00:12:13.240 --> 00:12:16.759
<v Speaker 3>Under normal conditions, those two vibrational modes are locked in

249
00:12:16.960 --> 00:12:21.679
<v Speaker 3>entirely separate, mathematically orthogonal rooms. But when you tune their

250
00:12:21.759 --> 00:12:26.840
<v Speaker 3>energies to align perfectly, the rules of symmetry become dynamically.

251
00:12:26.200 --> 00:12:29.240
<v Speaker 2>Loosened, dynamically loosen. I'm trying to picture the mechanics of that.

252
00:12:29.320 --> 00:12:31.919
<v Speaker 2>Does a symmetry just turn off like a light switch.

253
00:12:32.120 --> 00:12:36.039
<v Speaker 3>It doesn't turn off permanently, but at that exact resonant frequency,

254
00:12:36.519 --> 00:12:39.080
<v Speaker 3>the wave functions of the two modes are allowed to mix.

255
00:12:39.720 --> 00:12:43.279
<v Speaker 3>The amplitude essentially acts as a bridge, suddenly linking the

256
00:12:43.320 --> 00:12:47.120
<v Speaker 3>lower energy atomic motions with the higher energy electronic state

257
00:12:47.159 --> 00:12:47.759
<v Speaker 3>of the crystal.

258
00:12:47.879 --> 00:12:50.200
<v Speaker 2>So the soundproof wall gets a temporary window.

259
00:12:50.399 --> 00:12:52.080
<v Speaker 3>Yes, a window suddenly opens up.

260
00:12:52.360 --> 00:12:55.000
<v Speaker 2>It's like finding a hidden terms of service agreement in

261
00:12:55.039 --> 00:12:58.480
<v Speaker 2>the laws of physics, like symmetry applies strictly at all

262
00:12:58.559 --> 00:13:02.480
<v Speaker 2>times unless internal vibrations hit this exact resonant frequency.

263
00:13:02.559 --> 00:13:03.679
<v Speaker 3>That's exactly it.

264
00:13:03.720 --> 00:13:06.720
<v Speaker 2>And then the two locked rooms suddenly share a smuggler's tunnel,

265
00:13:06.919 --> 00:13:08.919
<v Speaker 2>passing quantum information back and forth.

266
00:13:09.039 --> 00:13:12.200
<v Speaker 3>It's a fundamental shift in how we view selection rules. Yeah,

267
00:13:12.279 --> 00:13:15.519
<v Speaker 3>the researchers didn't just observe this anomaly. They built a

268
00:13:15.559 --> 00:13:20.519
<v Speaker 3>comprehensive microscopic theory to explain the exact mechanics of how

269
00:13:20.519 --> 00:13:25.879
<v Speaker 3>these electronic fluctuations actively coupled to crystal vibrations that symmetry

270
00:13:25.960 --> 00:13:28.080
<v Speaker 3>usually keeps completely isolated.

271
00:13:28.480 --> 00:13:31.679
<v Speaker 2>That is a massive win for theoretical physics. But you

272
00:13:31.759 --> 00:13:33.960
<v Speaker 2>know me, I always want to know what this means. Practically,

273
00:13:34.279 --> 00:13:37.360
<v Speaker 2>finding a loophole on a chalkboard is great, but exploiting

274
00:13:37.440 --> 00:13:40.879
<v Speaker 2>it in the real world is where technology actually changes, and.

275
00:13:40.919 --> 00:13:43.320
<v Speaker 3>That transition to the real world is where a group

276
00:13:43.360 --> 00:13:46.480
<v Speaker 3>at the University of Hamburg comes into the picture. Michael

277
00:13:46.559 --> 00:13:50.080
<v Speaker 3>Rubhausen's group took these findings, confirmed the robustness of the

278
00:13:50.120 --> 00:13:53.559
<v Speaker 3>model and highlighted a point that completely transforms the utility

279
00:13:53.600 --> 00:13:54.399
<v Speaker 3>of this discovery.

280
00:13:54.480 --> 00:13:56.639
<v Speaker 2>Okay, what's the point this entire.

281
00:13:56.399 --> 00:14:00.759
<v Speaker 3>Effect, this resonant bridging, this loosening of symmetry, It operates

282
00:14:00.919 --> 00:14:02.360
<v Speaker 3>robustly at room temperature.

283
00:14:02.399 --> 00:14:04.480
<v Speaker 2>Wait, hold on, you have to explain how that is possible.

284
00:14:04.720 --> 00:14:08.919
<v Speaker 2>Every time we discuss exotic quantum states or delicate wave

285
00:14:08.919 --> 00:14:13.960
<v Speaker 2>functions mixing, we are talking about massive, multi million dollar

286
00:14:14.120 --> 00:14:17.879
<v Speaker 2>lab freezers chilling things down to near absolute zero.

287
00:14:18.080 --> 00:14:19.720
<v Speaker 3>Right usually, how.

288
00:14:19.559 --> 00:14:23.600
<v Speaker 2>On earth is this surviving the chaotic thermal noise of

289
00:14:23.639 --> 00:14:27.679
<v Speaker 2>a room temperature environment. Shouldn't the ambient heat just violently

290
00:14:27.720 --> 00:14:28.679
<v Speaker 2>scramble the pattern?

291
00:14:28.759 --> 00:14:33.120
<v Speaker 3>And most systems, yes, absolutely, Thermal fun ons cause rapid decoherence.

292
00:14:33.279 --> 00:14:36.840
<v Speaker 3>The heat destroys the delicate quantum states. But the coupling

293
00:14:36.879 --> 00:14:41.399
<v Speaker 3>here driven by this resonant bridging is incredibly strong. And

294
00:14:41.440 --> 00:14:44.759
<v Speaker 3>more importantly, it occurs on ultra fast time scales. Oh,

295
00:14:44.840 --> 00:14:48.000
<v Speaker 3>I see the interaction outpaces the thermal noise.

296
00:14:47.840 --> 00:14:49.879
<v Speaker 2>So it happens so fast the heat literally doesn't have

297
00:14:49.879 --> 00:14:51.120
<v Speaker 2>time to ruin it exactly.

298
00:14:51.480 --> 00:14:54.320
<v Speaker 3>This phenomenon has been termed resonant chiral dressing.

299
00:14:54.440 --> 00:14:56.480
<v Speaker 2>Chiral dressing. Okay, I want to make sure I understand

300
00:14:56.519 --> 00:14:59.000
<v Speaker 2>dressing in a quantum context. We aren't talking about putting

301
00:14:59.000 --> 00:15:00.600
<v Speaker 2>a tiny little coat on an atom.

302
00:15:00.440 --> 00:15:05.200
<v Speaker 3>Right, not quite a coat. In quantum mechanics, dressing refers

303
00:15:05.200 --> 00:15:08.559
<v Speaker 3>to how a material's fundamental properties are altered when it

304
00:15:08.679 --> 00:15:10.720
<v Speaker 3>strongly couples with a photon field.

305
00:15:10.840 --> 00:15:13.159
<v Speaker 2>A photon field so light yes.

306
00:15:13.080 --> 00:15:16.399
<v Speaker 3>In this case an ultrafast laser pulse. The light doesn't

307
00:15:16.440 --> 00:15:20.879
<v Speaker 3>just bounce off material, It temporarily merges with the material's identity,

308
00:15:21.240 --> 00:15:26.039
<v Speaker 3>creating a hybridized state. The crystal is dressed by the

309
00:15:26.080 --> 00:15:26.679
<v Speaker 3>light field.

310
00:15:26.799 --> 00:15:29.440
<v Speaker 2>So by using the right twist of light at the

311
00:15:29.519 --> 00:15:33.679
<v Speaker 2>exact right resonant frequency, you are temporarily dressing the material,

312
00:15:34.279 --> 00:15:38.120
<v Speaker 2>which bridges the symmetry gap, allowing these completely isolated quantum

313
00:15:38.120 --> 00:15:40.320
<v Speaker 2>states to talk to each other. Yes, and you can

314
00:15:40.360 --> 00:15:42.559
<v Speaker 2>do all of this sitting on a normal desk in

315
00:15:42.600 --> 00:15:44.279
<v Speaker 2>a normal room temperature lab.

316
00:15:44.440 --> 00:15:47.080
<v Speaker 3>You're starting to see the true power of this. It

317
00:15:47.120 --> 00:15:50.759
<v Speaker 3>provides a highly practical new route to probe and actively

318
00:15:50.799 --> 00:15:54.799
<v Speaker 3>control ferro axial quantum states without the crippling overhead of

319
00:15:54.840 --> 00:15:55.840
<v Speaker 3>cryogenic cooling.

320
00:15:56.080 --> 00:15:59.120
<v Speaker 2>That completely bypasses one of the biggest roadblocks in quantum

321
00:15:59.159 --> 00:15:59.960
<v Speaker 2>engineering today.

322
00:16:00.120 --> 00:16:03.279
<v Speaker 3>It really does. Scientists can now use ultrafast laser pulses

323
00:16:03.480 --> 00:16:07.000
<v Speaker 3>precisely tuned to these resonant energies to selectively turn on

324
00:16:07.120 --> 00:16:10.080
<v Speaker 3>these forbidden interactions. That's amating. You can dynamically switch a

325
00:16:10.159 --> 00:16:13.600
<v Speaker 3>quantum connection on and off just by hitting the crystal

326
00:16:13.639 --> 00:16:14.639
<v Speaker 3>with the right burst of light.

327
00:16:14.879 --> 00:16:18.679
<v Speaker 2>It's essentially a universal remote control for the microscopic world.

328
00:16:19.200 --> 00:16:21.519
<v Speaker 2>But instead of an infrared beam turning on a TV,

329
00:16:21.799 --> 00:16:25.960
<v Speaker 2>you're using a twisted ultrafast laser to flip the fundamental

330
00:16:26.000 --> 00:16:27.759
<v Speaker 2>symmetry of a crystal on and off.

331
00:16:28.360 --> 00:16:32.519
<v Speaker 3>The implications for future technologies are immense. We are talking

332
00:16:32.519 --> 00:16:37.480
<v Speaker 3>about entirely new paradigms for high density data storage, ultrasensitive

333
00:16:37.559 --> 00:16:42.639
<v Speaker 3>room temperature sensing technologies, and advanced computing architecture. Wow. If

334
00:16:42.639 --> 00:16:45.159
<v Speaker 3>you can manipulate the fundamental order of a material at

335
00:16:45.200 --> 00:16:48.679
<v Speaker 3>room temperature using light, you unlock a broad class of

336
00:16:48.720 --> 00:16:52.799
<v Speaker 3>materials that were previously thought to be completely static and untunable.

337
00:16:52.879 --> 00:16:55.639
<v Speaker 2>Okay, let's trace this entire journey back, because the physical

338
00:16:55.679 --> 00:16:59.200
<v Speaker 2>mechanics of what we've covered today are staggering. We started

339
00:16:59.200 --> 00:17:02.519
<v Speaker 2>with symmetry. Act is the ultimate unbreakable bouncer at the

340
00:17:02.519 --> 00:17:06.480
<v Speaker 2>club of the microscopic world. It built a cosmic soundproof

341
00:17:06.519 --> 00:17:09.119
<v Speaker 2>wall between the different vibrations and a crystal.

342
00:17:08.839 --> 00:17:11.720
<v Speaker 3>A rule we assumed was absolute.

343
00:17:11.440 --> 00:17:14.880
<v Speaker 2>Absolute, And then we looked at this specific layered crystal

344
00:17:15.319 --> 00:17:19.279
<v Speaker 2>where electrons bunch up into a charged density wave forming

345
00:17:19.319 --> 00:17:22.799
<v Speaker 2>these microscopic left and right handed star of David clusters,

346
00:17:23.359 --> 00:17:27.519
<v Speaker 2>a pattern that just sits there breathing, but is entirely

347
00:17:27.559 --> 00:17:30.759
<v Speaker 2>invisible to our best electric and magnetic sensors, a.

348
00:17:30.720 --> 00:17:33.359
<v Speaker 3>Ghost in the lattice until we learned to look at

349
00:17:33.400 --> 00:17:33.839
<v Speaker 3>it differently.

350
00:17:34.000 --> 00:17:37.720
<v Speaker 2>Right by using holicity resolved light work screw light, we

351
00:17:37.799 --> 00:17:40.839
<v Speaker 2>matched the physical twist of our optical screwdriver to the

352
00:17:40.880 --> 00:17:44.200
<v Speaker 2>microscopic handedness of the material, And once we could finally

353
00:17:44.240 --> 00:17:46.920
<v Speaker 2>map that ghost, we learned that by tuning the temperature,

354
00:17:47.160 --> 00:17:49.759
<v Speaker 2>we could essentially dial down the frequency of that breathing

355
00:17:49.759 --> 00:17:50.880
<v Speaker 2>amplitude on and.

356
00:17:50.799 --> 00:17:54.319
<v Speaker 3>The moment that frequency perfectly overlapped with an ordinary, forbidden

357
00:17:54.359 --> 00:17:55.480
<v Speaker 3>lattice vibration.

358
00:17:55.440 --> 00:17:58.440
<v Speaker 2>We found the secret tunnel, the resonant bridge, the wave

359
00:17:58.440 --> 00:18:02.119
<v Speaker 2>functions mixed, the rules of symmetry, we're dynamically bypassed, and

360
00:18:02.160 --> 00:18:05.519
<v Speaker 2>the two isolated rooms suddenly connected. Yes, and the absolute

361
00:18:05.519 --> 00:18:08.119
<v Speaker 2>best part is that this chiral dressing survives the chaotic

362
00:18:08.160 --> 00:18:10.559
<v Speaker 2>heat of room temperature. It gives us a way to

363
00:18:10.559 --> 00:18:13.599
<v Speaker 2>control quantum states with ultrafast lasers right here in the

364
00:18:13.640 --> 00:18:14.240
<v Speaker 2>real world.

365
00:18:14.599 --> 00:18:18.160
<v Speaker 3>It really serves as a powerful reminder of how dynamic

366
00:18:18.200 --> 00:18:21.640
<v Speaker 3>our understanding of the physical world truly is. Modern physics

367
00:18:21.680 --> 00:18:24.839
<v Speaker 3>is no longer just cataloging the rules of nature. It's

368
00:18:24.960 --> 00:18:28.640
<v Speaker 3>learning exactly how to find the resonant frequencies that rewrite

369
00:18:28.680 --> 00:18:31.960
<v Speaker 3>those rules totally. We are bridging the gap between theoretical

370
00:18:32.039 --> 00:18:35.200
<v Speaker 3>symmetry breaking and the tangible technology of tomorrow.

371
00:18:35.519 --> 00:18:39.039
<v Speaker 2>It's an incredible shift in perspective, and as we wrap

372
00:18:39.119 --> 00:18:41.160
<v Speaker 2>up our conversation today, I want to leave you with

373
00:18:41.200 --> 00:18:44.359
<v Speaker 2>one final thought, tam all over. If scientists can use

374
00:18:44.400 --> 00:18:47.720
<v Speaker 2>finely tuned light to dynamically bridge forbidden interactions in these

375
00:18:47.720 --> 00:18:52.279
<v Speaker 2>specific layered crystals, what other unbreakable laws of physics and

376
00:18:52.359 --> 00:18:55.200
<v Speaker 2>completely different materials might just be waiting for the exact

377
00:18:55.319 --> 00:18:58.279
<v Speaker 2>right frequency of light to be unlocked. Are there other

378
00:18:58.400 --> 00:19:03.160
<v Speaker 2>soundproof walls in nature holding back entirely new quantum technologies,

379
00:19:03.279 --> 00:19:05.200
<v Speaker 2>just waiting for us to find the perfect pitch to

380
00:19:05.240 --> 00:19:05.799
<v Speaker 2>shatter them.