En 2022, quelques équipes de scientifiques d'Oxford et de Vienne ont réussi un véritable tour de force. Ils ont mené cette expérience où ils ont divisé un photon en utilisant un peu de mojo de cristal sophistiqué. Et ce qui est incroyable, c'est que le photon a fini par voyager à la fois dans le passé et le futur ! C'est comme voyager dans le temps, mais avec un twist - parce que, vous savez, il y a toujours des exceptions à la règle. Mais hé, il est toujours sacrément cool de penser à cela, non ? Cela vous fait vous demander quel autres trucs fous attendent d'être découverts ! Animation créée par Sympa.
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Musique par Epidemic Sound https://www.epidemicsound.com
Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna
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Nos réseaux sociaux :
Facebook: https://www.facebook.com/sympasympacom/
Instagram: https://www.instagram.com/sympa.officiel/
Stock de fichiers (photos, vidéos et autres):
https://www.depositphotos.com
https://www.shutterstock.com
https://www.eastnews.ru
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Si tu en veux encore plus, fais un tour ici:
http://sympa-sympa.com
Category
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FunTranscript
00:00 Every day, the Earth bathes in the sunlight.
00:04 Every day, we turn on and off different sources of light,
00:08 mechanically, without even thinking about it.
00:10 But imagine that one day you turn off the light,
00:13 you fall asleep, and you wake up in a completely different time.
00:17 Let's see how this can happen, and what is the relationship with light.
00:21 Quantum physics is quite crazy.
00:25 Classical physics is like a movie projected from start to finish.
00:29 While the quantum world is like the possibility of taking the remote control
00:33 and manipulating the scenes you watch, fascinating and mysterious.
00:37 Let's suppose you have an ordinary switch that can be either turned on or off.
00:43 It's like an ordinary bit in computers, which can be in one of the following states, 0 or 1.
00:48 But in quantum computers, there is a particular type of switch called qubit.
00:53 Unlike ordinary bits, a qubit can exist in several states at the same time.
00:58 It can be both 0, 1, and everything.
01:01 What is between the two is like if the light could be simultaneously turned on and off.
01:07 Yes, the rules of our universe are weird.
01:09 This mysterious property called superposition has recently allowed us to achieve something incredible.
01:16 Go back in time, at least as part of a little experiment with quantum computers.
01:21 It's the fall of 2022.
01:23 Two groups of scientists, one from Oxford and the other from Vienna, decided to conduct a strange experiment.
01:29 They played with a quantum computer to create a program that reverses time.
01:34 They took a tiny electron and tried to make it go back in time for a fraction of a second.
01:39 As if, after breaking your triangle of balls at the billiards, and being put in chaos,
01:45 the whole process was reversed as if by magic.
01:48 But don't get too excited.
01:50 We are unfortunately not sure that it is possible to go back in time in real life.
01:55 By doing some calculations, scientists have discovered that if we observed
02:01 ten billion electrons localized for the entire duration of the universe,
02:04 we would only see such a phenomenon occur once.
02:07 And we are talking about a very small fraction of a second and a single electron.
02:11 So they didn't invent a machine to go back in time.
02:14 They just managed to create a simulation with quantum computers.
02:18 There is also another problem.
02:20 The bigger the simulation, the more complex it is and the less precise it is.
02:25 In our experiment, we only used one cubic meter and we managed to reverse time.
02:30 In a configuration with two cubic meters, scientists were only able to reverse time in 85% of the experiments.
02:36 In a configuration with three cubic meters, this percentage fell to 50%, with more errors.
02:42 If we continue to add cubic meters, we will not succeed at all.
02:45 In addition, success depends on the amount of information that the system can store.
02:50 For example, the teleportation of a person would be almost impossible
02:53 because humans contain a lot of information.
02:56 Alas, we do not yet have a machine to travel in time.
03:00 But this discovery can have some applications.
03:03 The inversion of the state of the cubic meters in a quantum processor
03:06 can correct the errors during development.
03:08 A little "Ctrl+Z", but in real life.
03:11 This represents a small step towards other exciting discoveries.
03:15 For example, they recently demonstrated another rather crazy thing.
03:19 We can send light itself into the past.
03:22 Light is not made only to illuminate.
03:25 It has superpowers that we cannot even imagine.
03:28 The Greeks of Antiquity thought that our eyes emitted visionary rays.
03:32 Isaac Newton gave them wrong hundreds of years later
03:35 when he conducted his experiments on prisms.
03:38 A prism breaks down pure white light into a magnificent palette.
03:42 This is how we discovered that light actually consists of a whole bunch of different colors.
03:48 Over time, scientists have learned something else.
03:51 That light is a wave.
03:53 Later, in the 20th century, we discovered a great paradox.
03:57 Light is both a wave and a particle.
04:00 A double existence in a single photon.
04:02 And the more we learn about light, the more we discover crazy things.
04:06 In 2016, scientists managed to freeze light in time.
04:11 They placed photons, the smallest particles of light, in ultra-cold atomic clouds.
04:17 And they managed to stop it.
04:19 But for a moment only.
04:20 However, the fact that such a thing is possible is already incredible.
04:23 Scientists then showed even more audacity.
04:27 They decided to try not only to freeze light, but also to change its direction in time.
04:33 They took a special crystal and passed a photon through it,
04:36 triggering what we call the quantum inversion of time.
04:40 Result?
04:41 The photon began to move both towards the future and towards the past.
04:45 Behind this phenomenon, there are two quantum principles.
04:48 The superposition and the quantum symmetry.
04:51 We have already mentioned the first,
04:53 which allows tiny particles to exist in several states at once.
04:56 The second principle states that even if you turn the particles like in a mirror,
05:00 they will always follow the same laws.
05:03 By combining these principles,
05:05 scientists have created a photon that defies the usual time walk.
05:09 But, again, not in a very complex way.
05:12 This temporal inversion only works for specific particles,
05:16 not for human beings.
05:18 And even if it worked for us,
05:20 winding a person would only take a second would take a lot of time and energy.
05:25 But the fact that we can change the speed of light and make it change direction is already amazing.
05:31 Scientists already see some possible applications.
05:34 For example, researchers at Harvard suggested a great way to move spacecraft at the speed of light,
05:41 by hooking them to supernovas.
05:43 In general, traveling to the stars requires a crazy amount of energy,
05:47 but these scientists have an extraordinary idea.
05:50 They think that spacecrafts could use natural elements,
05:54 like hypervelocity stars and meteors from supernovas,
05:57 to reach ultra-fast speeds.
06:00 Just like sailors use the wind to move forward.
06:03 Future civilizations could use these energy sources to accelerate their ships.
06:08 Imagine a spacecraft equipped with solar or magnetic sails,
06:12 which would exploit the power of an explosion of a supernova.
06:15 These high sails could use the pressure of solar radiation to operate.
06:19 So we would no longer need traditional engines or fuel.
06:23 In addition, these sailing machines would be much lighter and cheaper to launch into space than conventional spaceships.
06:30 A team is already working on a sail accelerated by lasers that could reach 20% of the speed of light.
06:36 It may seem little, but it's actually crazy fast.
06:39 Their dream is to help humanity make a quick trip to Alpha Centauri, in just two decades.
06:46 Isn't it amazing to see all that we can do with light?
06:50 And not only in our imagination, let's move on to more practical achievements.
06:54 Recently, a Canadian camouflage company, Hyperstealth Biotechnology Corporation,
07:00 has made a real invisibility cape.
07:03 This magic cape needs no energy source, is as thin as paper, and will not ruin you.
07:09 Hyperstealth envisions a world where this material could mask people,
07:14 vehicles, ships, spacecraft, and even entire buildings.
07:19 It's still a prototype, but it's already working very well.
07:23 They called this technology "quantum stealth".
07:27 Light is curved to make objects disappear.
07:31 This way, we can hide objects not only in the visible spectrum, but also in the ultraviolet, infrared,
07:37 short-wave infrared, and, to make good use of it, in the thermal spectrum.
07:42 This technology works with a lenticular lens, a wavy sheet with convex lenses.
07:48 When they are stacked in a specific way, these lenses refract light at different angles,
07:54 creating spots that block the light and hide the object.
07:58 Unfortunately, this does not allow for a total invisibility effect.
08:02 But maybe one day we will succeed. Let's keep working on it.
08:06 The cape gives the impression that a dirty or blurry glass stands in front of the one looking at it,
08:10 but the object it covers is no longer visible.
08:13 And if you place this veil in front of your body, you will have the impression that you are only a floating head.
08:18 Scientific progress is in full swing.
08:20 Maybe one day we will be able to reverse time not only for small particles of light,
08:25 but also for entire human beings.
08:27 In the meantime, let's take advantage of our invisibility caps and stay curious.
08:31 (upbeat music)