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Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.20,0:00:03.31,Default,,0000,0000,0000,,For most of our history, human\Ntechnology consisted of
Dialogue: 0,0:00:03.31,0:00:06.05,Default,,0000,0000,0000,,our brains, fire, and sharp sticks.
Dialogue: 0,0:00:06.63,0:00:10.10,Default,,0000,0000,0000,,While fire and sharp sticks became\Npower plants and nuclear weapons,
Dialogue: 0,0:00:10.10,0:00:12.69,Default,,0000,0000,0000,,the biggest upgrade has\Nhappened to our brains.
Dialogue: 0,0:00:13.13,0:00:17.62,Default,,0000,0000,0000,,Since the 1960s, the power of our brain\Nmachines has kept growing exponentially,
Dialogue: 0,0:00:17.62,0:00:21.79,Default,,0000,0000,0000,,allowing computers to get smaller\Nand more powerful at the same time.
Dialogue: 0,0:00:22.52,0:00:25.44,Default,,0000,0000,0000,,But this process is about\Nto meet its physical limits.
Dialogue: 0,0:00:25.83,0:00:28.72,Default,,0000,0000,0000,,Computer parts are approaching\Nthe size of an atom.
Dialogue: 0,0:00:29.39,0:00:32.69,Default,,0000,0000,0000,,To understand why this is a problem,\Nwe have to clear up some basics.
Dialogue: 0,0:00:39.67,0:00:43.90,Default,,0000,0000,0000,,A computer is made up of very simple\Ncomponents doing very simple things,
Dialogue: 0,0:00:43.90,0:00:48.47,Default,,0000,0000,0000,,representing data, the means of processing\Nit, and control mechanisms.
Dialogue: 0,0:00:49.06,0:00:50.68,Default,,0000,0000,0000,,Computer chips contain modules,
Dialogue: 0,0:00:50.68,0:00:53.91,Default,,0000,0000,0000,,which contain logic gates,\Nwhich contain transistors.
Dialogue: 0,0:00:54.56,0:00:58.46,Default,,0000,0000,0000,,A transistor is the simplest form\Nof a data processor in computers,
Dialogue: 0,0:00:58.46,0:01:01.56,Default,,0000,0000,0000,,basically, a switch that\Ncan either block or open
Dialogue: 0,0:01:01.56,0:01:03.48,Default,,0000,0000,0000,,the way for information coming through.
Dialogue: 0,0:01:03.94,0:01:08.46,Default,,0000,0000,0000,,This information is made up of bits,\Nwhich can be set to either zero or one.
Dialogue: 0,0:01:09.07,0:01:12.98,Default,,0000,0000,0000,,Combinations of several bits are used to\Nrepresent more complex information.
Dialogue: 0,0:01:13.50,0:01:18.02,Default,,0000,0000,0000,,Transistors are combined to create logic\Ngates, which still do very simple stuff.
Dialogue: 0,0:01:18.02,0:01:22.89,Default,,0000,0000,0000,,For example, an AND gate sends an output\Nof one if all of its inputs are one
Dialogue: 0,0:01:22.89,0:01:25.10,Default,,0000,0000,0000,,and an output of zero otherwise.
Dialogue: 0,0:01:25.66,0:01:28.98,Default,,0000,0000,0000,,Combinations of logic gates finally\Nform meaningful modules,
Dialogue: 0,0:01:28.98,0:01:31.07,Default,,0000,0000,0000,,say, for adding two numbers.
Dialogue: 0,0:01:31.45,0:01:35.13,Default,,0000,0000,0000,,Once you can add, you can also multiply,\Nand once you can multiply,
Dialogue: 0,0:01:35.13,0:01:36.85,Default,,0000,0000,0000,,you can basically do anything.
Dialogue: 0,0:01:37.48,0:01:41.04,Default,,0000,0000,0000,,Since all basic operations are literally\Nsimpler than first-grade math,
Dialogue: 0,0:01:41.04,0:01:43.73,Default,,0000,0000,0000,,you can imagine a computer as\Na group of seven-year-olds
Dialogue: 0,0:01:43.73,0:01:46.04,Default,,0000,0000,0000,,answering really basic math questions.
Dialogue: 0,0:01:46.58,0:01:50.72,Default,,0000,0000,0000,,A large enough bunch of them can compute\Nanything, from astrophysics to Zelda.
Dialogue: 0,0:01:51.28,0:01:53.62,Default,,0000,0000,0000,,However, with parts\Ngetting tinier and tinier,
Dialogue: 0,0:01:53.62,0:01:56.05,Default,,0000,0000,0000,,quantum physics are making things tricky.
Dialogue: 0,0:01:56.65,0:01:59.80,Default,,0000,0000,0000,,In a nutshell, a transistor\Nis just an electric switch.
Dialogue: 0,0:02:00.10,0:02:03.11,Default,,0000,0000,0000,,Electricity is electrons moving\Nfrom one place to another,
Dialogue: 0,0:02:03.11,0:02:07.82,Default,,0000,0000,0000,,so a switch is a passage that can block\Nelectrons from moving in one direction.
Dialogue: 0,0:02:08.41,0:02:11.68,Default,,0000,0000,0000,,Today, a typical scale\Nfor transistors is 14 nm,
Dialogue: 0,0:02:11.68,0:02:15.48,Default,,0000,0000,0000,,which is about 8 times less\Nthan the HIV virus’s diameter
Dialogue: 0,0:02:15.48,0:02:18.45,Default,,0000,0000,0000,,and 500 times smaller\Nthan a red blood cell’s.
Dialogue: 0,0:02:18.93,0:02:22.50,Default,,0000,0000,0000,,As transistors are shrinking\Nto the size of only a few atoms,
Dialogue: 0,0:02:22.50,0:02:25.93,Default,,0000,0000,0000,,electrons may just transfer themselves to\Nthe other side of a blocked passage
Dialogue: 0,0:02:25.93,0:02:28.17,Default,,0000,0000,0000,,via a process called quantum tunneling.
Dialogue: 0,0:02:28.64,0:02:31.65,Default,,0000,0000,0000,,In the quantum realm, physics\Nworks quite differently from
Dialogue: 0,0:02:31.65,0:02:33.36,Default,,0000,0000,0000,,the predictable ways we’re used to,
Dialogue: 0,0:02:33.36,0:02:36.56,Default,,0000,0000,0000,,and traditional computers\Njust stop making sense.
Dialogue: 0,0:02:37.07,0:02:40.94,Default,,0000,0000,0000,,We are approaching a real physical\Nbarrier for our technological progress.
Dialogue: 0,0:02:41.66,0:02:44.00,Default,,0000,0000,0000,,To solve this problem,\Nscientists are trying to
Dialogue: 0,0:02:44.00,0:02:47.02,Default,,0000,0000,0000,,use these unusual quantum\Nproperties to their advantage
Dialogue: 0,0:02:47.02,0:02:49.05,Default,,0000,0000,0000,,by building quantum computers.
Dialogue: 0,0:02:49.66,0:02:53.14,Default,,0000,0000,0000,,In normal computers, bits\Nare the smallest units of information.
Dialogue: 0,0:02:53.61,0:02:57.79,Default,,0000,0000,0000,,Quantum computers use qubits, which\Ncan also be set to one of two values.
Dialogue: 0,0:02:58.29,0:03:00.61,Default,,0000,0000,0000,,A qubit can be any\Ntwo-level quantum system,
Dialogue: 0,0:03:00.61,0:03:04.29,Default,,0000,0000,0000,,such as a spin in a magnetic field\Nor a single photon.
Dialogue: 0,0:03:04.58,0:03:07.52,Default,,0000,0000,0000,,Zero and one are this\Nsystem’s possible states,
Dialogue: 0,0:03:07.52,0:03:10.68,Default,,0000,0000,0000,,like the photon’s horizontal\Nor vertical polarization.
Dialogue: 0,0:03:11.15,0:03:14.52,Default,,0000,0000,0000,,In the quantum world, the qubit\Ndoesn’t have to be in just one of those;
Dialogue: 0,0:03:14.52,0:03:17.66,Default,,0000,0000,0000,,it can be in any proportions\Nof both states at once.
Dialogue: 0,0:03:17.90,0:03:19.90,Default,,0000,0000,0000,,This is called superposition.
Dialogue: 0,0:03:20.36,0:03:24.27,Default,,0000,0000,0000,,But as soon as you test its value, say,\Nby sending the photon through a filter,
Dialogue: 0,0:03:24.27,0:03:28.66,Default,,0000,0000,0000,,it has to decide to be either\Nvertically or horizontally polarized.
Dialogue: 0,0:03:29.23,0:03:33.72,Default,,0000,0000,0000,,So, as long as it’s unobserved, the qubit\Nis in a superposition of probabilities
Dialogue: 0,0:03:33.72,0:03:36.95,Default,,0000,0000,0000,,for zero and one, and you can’t\Npredict which it will be.
Dialogue: 0,0:03:37.62,0:03:41.69,Default,,0000,0000,0000,,But the instant you measure it, it\Ncollapses into one of the definite states.
Dialogue: 0,0:03:42.38,0:03:44.54,Default,,0000,0000,0000,,Superposition is a game-changer.
Dialogue: 0,0:03:45.27,0:03:48.23,Default,,0000,0000,0000,,Four classical bits can be\Nin one of 2 to the power of 4
Dialogue: 0,0:03:48.23,0:03:50.04,Default,,0000,0000,0000,,different configurations at a time.
Dialogue: 0,0:03:50.42,0:03:54.40,Default,,0000,0000,0000,,That’s 16 possible combinations,\Nout of which you can use just one.
Dialogue: 0,0:03:54.96,0:03:57.02,Default,,0000,0000,0000,,Four qubits in superposition, however,
Dialogue: 0,0:03:57.02,0:04:00.20,Default,,0000,0000,0000,,can be in all of those\N16 combinations at once!
Dialogue: 0,0:04:00.88,0:04:04.02,Default,,0000,0000,0000,,This number grows exponentially\Nwith each extra qubit.
Dialogue: 0,0:04:04.53,0:04:08.11,Default,,0000,0000,0000,,20 of them can already store\Na million values in parallel.
Dialogue: 0,0:04:08.78,0:04:11.68,Default,,0000,0000,0000,,A really weird an unintuitive\Nproperty qubits can have
Dialogue: 0,0:04:11.68,0:04:15.15,Default,,0000,0000,0000,,is entanglement, a close connection that\Nmakes each of the qubits
Dialogue: 0,0:04:15.15,0:04:17.97,Default,,0000,0000,0000,,react to a change in the other’s\Nstate instantaneously,
Dialogue: 0,0:04:17.97,0:04:20.08,Default,,0000,0000,0000,,no matter how far they are apart.
Dialogue: 0,0:04:20.56,0:04:23.25,Default,,0000,0000,0000,,This means that when measuring\Njust one entangled qubit,
Dialogue: 0,0:04:23.25,0:04:27.56,Default,,0000,0000,0000,,you can directly deduce properties of\Nits partners without having to look.
Dialogue: 0,0:04:27.94,0:04:30.72,Default,,0000,0000,0000,,Qubit manipulation\Nis a mind-bender as well.
Dialogue: 0,0:04:31.12,0:04:34.01,Default,,0000,0000,0000,,A normal logic gate gets\Na simple set of inputs
Dialogue: 0,0:04:34.01,0:04:36.13,Default,,0000,0000,0000,,and produces one definite output.
Dialogue: 0,0:04:36.65,0:04:39.86,Default,,0000,0000,0000,,A quantum gate manipulates\Nan input of superpositions,
Dialogue: 0,0:04:39.86,0:04:44.78,Default,,0000,0000,0000,,rotates probabilities, and produces\Nanother superposition as its output.
Dialogue: 0,0:04:45.43,0:04:49.96,Default,,0000,0000,0000,,So a quantum computer sets up some qubits,\Napplies quantum gates to entangle them
Dialogue: 0,0:04:49.96,0:04:53.17,Default,,0000,0000,0000,,and manipulate probabilities,\Nthen finally measures the outcome,
Dialogue: 0,0:04:53.17,0:04:57.50,Default,,0000,0000,0000,,collapsing superpositions to an\Nactual sequence of zeros and ones.
Dialogue: 0,0:04:57.99,0:05:00.100,Default,,0000,0000,0000,,What this means is that you\Nget the entire lot of calculations
Dialogue: 0,0:05:00.100,0:05:04.14,Default,,0000,0000,0000,,that are possible with your setup\Nall done at the same time.
Dialogue: 0,0:05:04.73,0:05:06.90,Default,,0000,0000,0000,,Ultimately, you can only\Nmeasure one of the results,
Dialogue: 0,0:05:06.90,0:05:09.47,Default,,0000,0000,0000,,and it will only probably\Nbe the one you want,
Dialogue: 0,0:05:09.47,0:05:11.70,Default,,0000,0000,0000,,so you may have to\Ndouble-check and try again.
Dialogue: 0,0:05:12.72,0:05:15.89,Default,,0000,0000,0000,,But by cleverly exploiting\Nsuperposition and entanglement,
Dialogue: 0,0:05:15.89,0:05:17.89,Default,,0000,0000,0000,,this can be exponentially more efficient
Dialogue: 0,0:05:17.89,0:05:20.43,Default,,0000,0000,0000,,than would ever be possible\Non a normal computer.
Dialogue: 0,0:05:21.75,0:05:25.46,Default,,0000,0000,0000,,So, while quantum computers will probably\Nnot replace our home computers,
Dialogue: 0,0:05:25.46,0:05:28.20,Default,,0000,0000,0000,,in some areas they are vastly superior.
Dialogue: 0,0:05:28.77,0:05:30.46,Default,,0000,0000,0000,,One of them is database searching.
Dialogue: 0,0:05:30.82,0:05:32.26,Default,,0000,0000,0000,,To find something in a database,
Dialogue: 0,0:05:32.26,0:05:35.48,Default,,0000,0000,0000,,a normal computer may have\Nto test every single one of its entries.
Dialogue: 0,0:05:36.02,0:05:38.81,Default,,0000,0000,0000,,Quantum algorithms need only\Nthe square root of that time,
Dialogue: 0,0:05:38.81,0:05:41.93,Default,,0000,0000,0000,,which for large databases\Nis a huge difference.
Dialogue: 0,0:05:42.76,0:05:46.60,Default,,0000,0000,0000,,The most famous use of quantum\Ncomputers is ruining IT security.
Dialogue: 0,0:05:47.24,0:05:49.75,Default,,0000,0000,0000,,Right now, your browsing,\Nemail, and banking data
Dialogue: 0,0:05:49.75,0:05:53.19,Default,,0000,0000,0000,,is being kept secure by an encryption\Nsystem in which you give everyone
Dialogue: 0,0:05:53.19,0:05:56.59,Default,,0000,0000,0000,,a public key to encode\Nmessages only you can decode.
Dialogue: 0,0:05:57.06,0:05:59.89,Default,,0000,0000,0000,,The problem is that this\Npublic key can actually be used
Dialogue: 0,0:05:59.89,0:06:02.01,Default,,0000,0000,0000,,to calculate your secret private key.
Dialogue: 0,0:06:02.54,0:06:05.52,Default,,0000,0000,0000,,Luckily, doing the necessary math\Non any normal computer
Dialogue: 0,0:06:05.52,0:06:07.69,Default,,0000,0000,0000,,would literally take\Nyears of trial and error.
Dialogue: 0,0:06:08.11,0:06:10.52,Default,,0000,0000,0000,,But a quantum computer\Nwith exponential speedup
Dialogue: 0,0:06:10.52,0:06:11.91,Default,,0000,0000,0000,,could do it in a breeze.
Dialogue: 0,0:06:12.64,0:06:15.34,Default,,0000,0000,0000,,Another really exciting\Nnew use is simulations.
Dialogue: 0,0:06:15.80,0:06:18.90,Default,,0000,0000,0000,,Simulations of the quantum world\Nare very intense on resources,
Dialogue: 0,0:06:18.90,0:06:22.06,Default,,0000,0000,0000,,and even for bigger structures,\Nsuch as molecules,
Dialogue: 0,0:06:22.06,0:06:23.95,Default,,0000,0000,0000,,they often lack accuracy.
Dialogue: 0,0:06:24.50,0:06:28.25,Default,,0000,0000,0000,,So why not simulate quantum physics\Nwith actual quantum physics?
Dialogue: 0,0:06:29.00,0:06:31.89,Default,,0000,0000,0000,,Quantum simulations could provide\Nnew insights on proteins
Dialogue: 0,0:06:31.89,0:06:33.78,Default,,0000,0000,0000,,that might revolutionize medicine.
Dialogue: 0,0:06:34.40,0:06:36.88,Default,,0000,0000,0000,,Right now we don’t know\Nif quantum computers will be
Dialogue: 0,0:06:36.88,0:06:40.68,Default,,0000,0000,0000,,just a very specialized tool\Nor a big revolution for humanity.
Dialogue: 0,0:06:41.09,0:06:43.73,Default,,0000,0000,0000,,We have no idea where\Nthe limits of technology are,
Dialogue: 0,0:06:43.73,0:06:45.86,Default,,0000,0000,0000,,and there’s only one way to find out!
Dialogue: 0,0:06:47.56,0:06:50.62,Default,,0000,0000,0000,,This video is supported by\Nthe Australian Academy of Science,
Dialogue: 0,0:06:50.62,0:06:53.52,Default,,0000,0000,0000,,which promotes and\Nsupports excellence in science.
Dialogue: 0,0:06:54.42,0:06:56.60,Default,,0000,0000,0000,,Learn more about this topic\Nand others like it
Dialogue: 0,0:06:56.60,0:06:58.57,Default,,0000,0000,0000,,at .
Dialogue: 0,0:06:58.91,0:07:01.92,Default,,0000,0000,0000,,It was a blast to work with them,\Nso go check out their site!
Dialogue: 0,0:07:02.39,0:07:06.07,Default,,0000,0000,0000,,Our videos are also made possible\Nby your support on Patreon.com.
Dialogue: 0,0:07:06.63,0:07:10.80,Default,,0000,0000,0000,,If you want to support us and become part\Nof the Kurzgesagt bird army,
Dialogue: 0,0:07:10.80,0:07:12.36,Default,,0000,0000,0000,,check out our Patreon page!