ABOUT THE SPEAKER
Allan Adams - Theoretical physicist
Allan Adams is a theoretical physicist working at the intersection of fluid dynamics, quantum field theory and string theory.

Why you should listen

Allan Adams is a theoretical physicist working at the intersection of fluid dynamics, quantum field theory and string theory. His research in theoretical physics focuses on string theory both as a model of quantum gravity and as a strong-coupling description of non-gravitational systems.

Like water, string theory enjoys many distinct phases in which the low-energy phenomena take qualitatively different forms. In its most familiar phases, string theory reduces to a perturbative theory of quantum gravity. These phases are useful for studying, for example, the resolution of singularities in classical gravity, or the set of possibilities for the geometry and fields of spacetime. Along these lines, Adams is particularly interested in microscopic quantization of flux vacua, and in the search for constraints on low-energy physics derived from consistency of the stringy UV completion.

In other phases, when the gravitational interactions become strong and a smooth spacetime geometry ceases to be a good approximation, a more convenient description of string theory may be given in terms of a weakly-coupled non-gravitational quantum field theory. Remarkably, these two descriptions—with and without gravity—appear to be completely equivalent, with one remaining weakly-coupled when its dual is strongly interacting. This equivalence, known as gauge-gravity duality, allows us to study strongly-coupled string and quantum field theories by studying perturbative features of their weakly-coupled duals. Gauge-gravity duals have already led to interesting predictions for the quark-gluon plasma studied at RHIC. A major focus of Adams's present research is to use such dualities to find weakly-coupled descriptions of strongly-interacting condensed matter systems which can be realized in the lab.
More profile about the speaker
Allan Adams | Speaker | TED.com
TED2014

Allan Adams: The discovery that could rewrite physics

Filmed:
1,865,923 views

On March 17, 2014, a group of physicists announced a thrilling discovery: the “smoking gun” data for the idea of an inflationary universe, a clue to the Big Bang. For non-physicists, what does it mean? TED asked Allan Adams to briefly explain the results, in this improvised talk illustrated by Randall Munroe of xkcd.
- Theoretical physicist
Allan Adams is a theoretical physicist working at the intersection of fluid dynamics, quantum field theory and string theory. Full bio

Double-click the English transcript below to play the video.

00:12
If you look deep into the night sky,
0
928
3492
00:16
you see stars,
1
4420
1616
00:18
and if you look further, you see more stars,
2
6036
2572
00:20
and further, galaxies, and
further, more galaxies.
3
8608
2159
00:22
But if you keep looking further and further,
4
10767
3873
00:26
eventually you see nothing for a long while,
5
14640
3116
00:29
and then finally you see a
faint, fading afterglow,
6
17756
4462
00:34
and it's the afterglow of the Big Bang.
7
22218
3024
00:37
Now, the Big Bang was an era in the early universe
8
25242
2817
00:40
when everything we see in the night sky
9
28059
2171
00:42
was condensed into an incredibly small,
10
30230
2410
00:44
incredibly hot, incredibly roiling mass,
11
32640
4326
00:48
and from it sprung everything we see.
12
36966
2692
00:51
Now, we've mapped that afterglow
13
39658
2859
00:54
with great precision,
14
42517
1679
00:56
and when I say we, I mean people who aren't me.
15
44196
2044
00:58
We've mapped the afterglow
16
46240
1876
01:00
with spectacular precision,
17
48116
1322
01:01
and one of the shocks about it
18
49438
1548
01:02
is that it's almost completely uniform.
19
50986
2946
01:05
Fourteen billion light years that way
20
53932
1958
01:07
and 14 billion light years that way,
21
55890
1860
01:09
it's the same temperature.
22
57750
1408
01:11
Now it's been 14 billion years
23
59158
3314
01:14
since that Big Bang,
24
62472
1818
01:16
and so it's got faint and cold.
25
64290
2472
01:18
It's now 2.7 degrees.
26
66762
2308
01:21
But it's not exactly 2.7 degrees.
27
69070
2280
01:23
It's only 2.7 degrees to about
28
71350
2294
01:25
10 parts in a million.
29
73644
1842
01:27
Over here, it's a little hotter,
30
75486
994
01:28
and over there, it's a little cooler,
31
76480
1868
01:30
and that's incredibly important
to everyone in this room,
32
78348
3088
01:33
because where it was a little hotter,
33
81436
1724
01:35
there was a little more stuff,
34
83160
1696
01:36
and where there was a little more stuff,
35
84856
1567
01:38
we have galaxies and clusters of galaxies
36
86423
1969
01:40
and superclusters
37
88392
1252
01:41
and all the structure you see in the cosmos.
38
89644
2708
01:44
And those small, little, inhomogeneities,
39
92352
3112
01:47
20 parts in a million,
40
95464
2282
01:49
those were formed by quantum mechanical wiggles
41
97746
2754
01:52
in that early universe that were stretched
42
100500
1808
01:54
across the size of the entire cosmos.
43
102308
2279
01:56
That is spectacular,
44
104587
1714
01:58
and that's not what they found on Monday;
45
106301
1665
01:59
what they found on Monday is cooler.
46
107966
2036
02:02
So here's what they found on Monday:
47
110002
2266
02:04
Imagine you take a bell,
48
112268
3503
02:07
and you whack the bell with a hammer.
49
115771
1611
02:09
What happens? It rings.
50
117382
1676
02:11
But if you wait, that ringing fades
51
119058
2208
02:13
and fades and fades
52
121266
1620
02:14
until you don't notice it anymore.
53
122886
1942
02:16
Now, that early universe was incredibly dense,
54
124828
2648
02:19
like a metal, way denser,
55
127476
2079
02:21
and if you hit it, it would ring,
56
129555
2405
02:23
but the thing ringing would be
57
131960
1863
02:25
the structure of space-time itself,
58
133823
2088
02:27
and the hammer would be quantum mechanics.
59
135911
2816
02:30
What they found on Monday
60
138727
1931
02:32
was evidence of the ringing
61
140658
2362
02:35
of the space-time of the early universe,
62
143020
2315
02:37
what we call gravitational waves
63
145335
2105
02:39
from the fundamental era,
64
147440
1520
02:40
and here's how they found it.
65
148960
1975
02:42
Those waves have long since faded.
66
150935
2072
02:45
If you go for a walk,
67
153007
1488
02:46
you don't wiggle.
68
154495
1588
02:48
Those gravitational waves in the structure of space
69
156083
2748
02:50
are totally invisible for all practical purposes.
70
158831
2774
02:53
But early on, when the universe was making
71
161605
2904
02:56
that last afterglow,
72
164509
2370
02:58
the gravitational waves
73
166879
1558
03:00
put little twists in the structure
74
168437
2863
03:03
of the light that we see.
75
171300
1527
03:04
So by looking at the night sky deeper and deeper --
76
172827
2966
03:07
in fact, these guys spent
three years on the South Pole
77
175793
2638
03:10
looking straight up through the coldest, clearest,
78
178431
2589
03:13
cleanest air they possibly could find
79
181020
2350
03:15
looking deep into the night sky and studying
80
183370
2429
03:17
that glow and looking for the faint twists
81
185799
3376
03:21
which are the symbol, the signal,
82
189175
2348
03:23
of gravitational waves,
83
191523
1820
03:25
the ringing of the early universe.
84
193343
2341
03:27
And on Monday, they announced
85
195684
1787
03:29
that they had found it.
86
197471
1744
03:31
And the thing that's so spectacular about that to me
87
199215
2427
03:33
is not just the ringing, though that is awesome.
88
201642
2748
03:36
The thing that's totally amazing,
89
204390
1358
03:37
the reason I'm on this stage, is because
90
205748
2102
03:39
what that tells us is something
deep about the early universe.
91
207850
3468
03:43
It tells us that we
92
211318
1664
03:44
and everything we see around us
93
212982
1436
03:46
are basically one large bubble --
94
214418
2954
03:49
and this is the idea of inflation—
95
217372
1756
03:51
one large bubble surrounded by something else.
96
219128
3892
03:55
This isn't conclusive evidence for inflation,
97
223020
2130
03:57
but anything that isn't inflation that explains this
98
225150
2174
03:59
will look the same.
99
227324
1317
04:00
This is a theory, an idea,
100
228641
1645
04:02
that has been around for a while,
101
230286
1224
04:03
and we never thought we we'd really see it.
102
231510
1725
04:05
For good reasons, we thought we'd never see
103
233235
1838
04:07
killer evidence, and this is killer evidence.
104
235073
2248
04:09
But the really crazy idea
105
237321
2010
04:11
is that our bubble is just one bubble
106
239331
3032
04:14
in a much larger, roiling pot of universal stuff.
107
242363
4626
04:18
We're never going to see the stuff outside,
108
246989
1826
04:20
but by going to the South Pole
and spending three years
109
248815
2574
04:23
looking at the detailed structure of the night sky,
110
251389
2560
04:25
we can figure out
111
253949
1856
04:27
that we're probably in a universe
that looks kind of like that.
112
255805
3090
04:30
And that amazes me.
113
258895
2422
04:33
Thanks a lot.
114
261317
1336
04:34
(Applause)
115
262653
2936

▲Back to top

ABOUT THE SPEAKER
Allan Adams - Theoretical physicist
Allan Adams is a theoretical physicist working at the intersection of fluid dynamics, quantum field theory and string theory.

Why you should listen

Allan Adams is a theoretical physicist working at the intersection of fluid dynamics, quantum field theory and string theory. His research in theoretical physics focuses on string theory both as a model of quantum gravity and as a strong-coupling description of non-gravitational systems.

Like water, string theory enjoys many distinct phases in which the low-energy phenomena take qualitatively different forms. In its most familiar phases, string theory reduces to a perturbative theory of quantum gravity. These phases are useful for studying, for example, the resolution of singularities in classical gravity, or the set of possibilities for the geometry and fields of spacetime. Along these lines, Adams is particularly interested in microscopic quantization of flux vacua, and in the search for constraints on low-energy physics derived from consistency of the stringy UV completion.

In other phases, when the gravitational interactions become strong and a smooth spacetime geometry ceases to be a good approximation, a more convenient description of string theory may be given in terms of a weakly-coupled non-gravitational quantum field theory. Remarkably, these two descriptions—with and without gravity—appear to be completely equivalent, with one remaining weakly-coupled when its dual is strongly interacting. This equivalence, known as gauge-gravity duality, allows us to study strongly-coupled string and quantum field theories by studying perturbative features of their weakly-coupled duals. Gauge-gravity duals have already led to interesting predictions for the quark-gluon plasma studied at RHIC. A major focus of Adams's present research is to use such dualities to find weakly-coupled descriptions of strongly-interacting condensed matter systems which can be realized in the lab.
More profile about the speaker
Allan Adams | Speaker | TED.com