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WELCOME TO THE QUANTUM ERA
The beginning od the3. decade of the 21. century is starting the era of quant and quantum computer and simultaneous the end of the era of classic computer based on chips and transistors,
Welcome into the new era , where we need to forget everytheig we know cause end effect, reality, certanlity, and mch else besides This is, includ the future quantum computer, the different world, it has its own rules, rules of probability theat make no sense in our everyday world.
Richard Feynman, the greatest phisicist of his genration, said of quantum theory: "It is impossible to explain it in any classical way. T he same refers to the quantum and quantum computer.
Quantum theory is much more than just bizarre, it is also without doubt the most amazing theory in existence.
This is very complex theory.
David Deutsch, born i Haifa ( Israel), an Oxford phisicist and author of "The Faabric of Reality: The Science of Parallel Universes-- and Its Implicaations", said: "Our universe is just one of many, linked together by the astounding henomena of the quantum world. David Deutsch beleives tčhis multiverse view of raaliti could hold the future of copmputing.
A growing number of physicist, myself included, are convinced that thing we call 'the universe' - - namely space, with all the matter and energy it contains - is not the whoole of reality, According to quantum tgheory - the deepest theory known to physics - our uneverse is only a tiny facet of a larger multiverse , a highly structured continuum containing many uneverses.
Everything in our universe -- including you and me, every atom and every galaxy -- has counterparts in these other universes. Some counterparts are in the same places as they are in our universe, while others are in different places. Some have different shapes, or are arranged in different ways; some are so different that they are not worth calling counterparts. There are even universes in which a give object in our iniverse has no counterpart --including universes in which I was never born and you wrote this article instead.
Through interference each particle in our universe can be affected by its counterparts in other universes. What we see as a single subatomic particle is really a sprawling transuniverse structure, spanning a large region of the multiverse. Although we cannot see the parts of this structure that are outside our iniverse, we can infer their presence from the results of experiments. Perhaps the most striking involve quantum computers -- devices that collaborate with nearby universes to perform useful computations.
How do they do that? While conventional, non-quantum computers perform calculations on fundamental pieces of informations called bits, which can take the values 0 ili 1, quantum compusters use objects called quantum bits, or qubits. A qubit can also either represent 0 or 1, but its value can vary from iniverse to universe.
Hence in the time it takes a conventional domputer to perform a given calculation, a quantum computer with its counsterparts in other universes can perform many such calculations. In particular, they can each perform different piecaes of a complex computation simultaneously. Using quantum interference, the computer in our iniverse can then combine its results with those of its counterparts, to arrive at the overall answer.
Not all types of computatuion are capable of being shared out among iniverses in this way. Within one universe we are free to shuffle information about from place to place, and to perform whatever logical operations we like on it, but in the multiverse, things are not so convenient.
Quantum computers, nevertheless, offer fundamentallz new capabilities, including absolutely secaure methods of communication, ways of breaking the best existing codes and seemingly miraculous algorithms for solving mathematical problems that are currently intractable.
For instancae, "Deep Blue", IBM's chess-playing supercomputer had examined about 200 million chess positions per second by sharing the work amnog its 256 processors, each of which examined almost one million positions per second..
Quantum computer, running a search algorithm discovered by Lov Grover of AT&T's Bell Laboratiories in New Jersey could autclass Deep Blue by sharing the work among meny unererses. Grover proved that if there were time to searach N items using a conventional computer in one universe, his algorithm could exploit the multivrse to search a total of N2 items in the same time. Thus a single quantum mprocessor, with the same clock rate as one of Deep Blue's processors could examine a trillion chess positions in one seacond --- and in two seconds it could examine four trillion, in three seconds nine trillion, and so on.
Research groups worldwide are now racing to build the first practical quantum computer. The contemporary level of development is modest and has the capacity of only a handful of qubits each, but they can alredy demonstrate modes of computation that no existing computer can march.
But to explain exactly how they will work, some form of multiple-universe language is unavoidable. Thus quantum computers provide irresistible evidence that the multiverse is real. One especially convincing argument is provided by quantum algorithms --- even more powerful than Grover's ---which calculate more intermediate results in the course of an single computatuon than the are atoms in the visible universe.
When a quantum computer delivers the output of such a computation, we shall know that those intermediate results must have been computed somewhere, because they were needed to procuce the right answer, So I (David Deutsch)) issue this challenge to those who still cling to a single- universe world view: if the universe we see around us is all there is, where are quantum computations performed?
One major school of quantum theory posits a multiiplicity of universes; but what does that imply about the reality we live in? A simple experiment, familiar to every student of phisics, involves light passing through slits in a barrier; its results, accaording to Oxford physicist Deutsch, lead inevitably to the idea that there are countless universess parallel to our own, through which some of the light must pass. This "many worlds" interpretation of quantum theory has gained advocates in recent years, and Deutsch argues that it is time for scaientists to face the full implications of this idea. After all, the entire point of science is to help us understand the world we live in.
Deutsch argues that quantum computatuin, a discipline in which he is a pioneering thinker, has the potential for building computers that draw on their counterparts in parallel universes; this could amde artificial intellinence a reality. Likewise, time travel into both the future and the past should be possible, though not in quite the form envisioned by science fiction writers; the trips would almost bi one-way, and they would likely take the travelers into different worlds.
Parallel universes are no longer a figment of our imagination. They are so real that we can reach and touch them, and even use them to change our world.Why beleive in something so extraordinary? Because it can explain one of the greatest mysteries of modern science = why the world of atoms behaves so very differently from the every world of trees and tables.
The many worlds interpretation is one way to do it. This idea was proposed by Princeton graduate student Hugh Everett in 1957. Acacording to many worlds, quantum theory doesn't just apply to atoms, says Deutsch. But, if the tables can be in many places at once, the world of tables is exactly the same as the world of atoms. Right. But, nobody has ever seen such a schizoprenic table. So what gives?
Hugh Evertt
The idea is that if you observe a table that is in two places an once, there are also two versions of you-one that sees the table in one place and one that sees it in another place.The consequences are remarkable. A universe must exist for every phisical possibility, There are Earts where the Nazis prevailed in the Second World War, where Marilyn Monroe married Einstein, and where the dinosaurs survived and evolved into intelligent beings who read New Scientist
That all seems inexplicable and impossible but in the theory and law of quantum mechanic is all possible. We are going there.
However, many worlds is not the only interpretation of quantum theory. Physicists can chose between half a dozen interpretaions, all of which predict identical outcomes for all conceivable experiments.
Deutsch dismisses them all. "Some are gibberish, like Copenhagen interpretation." he says- and the rest are just variations on the many worlda theme.
For example, accoridng to the Copenhaben interpretation, tha act of observing is that this only requires a large-scale objects such as a particle detectors. For others it means an interactoon with some kind of conscious being, But, where is this Being?.
Worse still, says Deutsch, is that in this type of interpretation you have to abandom the idea of rrality. Before observationatha atom doesn't have a real position. Todeutsch the whole thing is mysticism-throwing up our hands and saying the are some things we are not allowed to ask
Some interpretations do try to give the microscopic world raality, but they are all disguised versions of the many worlds idea, says Deutsch. "They proponents have fallen over backwards to talk about the many worlds in a way that makes it appear as if they are not".
In this category, Deutsch includes David Bohm's "pilot-wave" interpretation. Bohm's idea is that a quantum wave guides particles along their trajectories. Then the idea is that a quantum wave guide particles along their trajectories.Then the strange shape of the pilot wave can bi used to explain all the odd quantum behaviours, such an interference patterns. In effect, says Deutsch, Bohm's single universe occupies one groove in an immensely complicated multi-dimensional wave function. Thus ,quantum is more and more bizarre.
David Bohm
The question that pilot-wave theorists must address is: whati are the unoccupied grooves?" says Deutsch. "It is no good saying they are merily theoretical and do not exist physically, for they continually jostle each other and the occupied groove, affecting its trajectory. What's really being talked about here is parallel universes. Pilot-wave theories are parallel- universe theories in a state of chronic denial.
Back and forth
Another disguised many world theory, says Deutsch, is John Cramer's "tranactional" interpretation in which information passes backwards and forwards through time. When you measure the position of an atom, it sends a message back to its earlier self to change its trajectory accordingly.
John Cramer
The capability of quantum demonstrates the power of the future quantum computer.
As the system gets more complicated, the number of messages explodes. Soon, says Deutsch, it becomes vastly greater then the mumber of paticles in the Universe. The full quantum evolution of a system is big as the Universe consists of an exponentially large number of classical processes, each of which contains the information to describe a whole iniverse. So Cramer's idea forces the multiverse on you, says Deutsch.
So do other interpretations, according to Deutsch. Quantum teory leaves no doubt that other universes exist in exactly the same sense that the single Universe that we see exists," he says. This is not a matter of Interpretation. It is a logical cnosequence of quantum theory."
A much more legitimate objection is that many worlds is vague and has no firm mathematical basis. Proponents talk of a multiverse that is like a stack of parallel universes. The critics point out that it cannot be that simple quantum phenomena occur precisely because the universes interact. "What is needed is a precise mathematical model of the multiverse," says Deutsch. And now he's made one and is going counter himself.
Many physicists opoosit to Deutsch. They say, the key to Deutsch's model sounds peculiar. He treats sthe multiverse as if it were a quantum computer. Quantum computers exploit the strangeness of quantum systems-their ability to be in many states at once-to do certain kinds of calculation at ludcrously high speed For exasmple, sthey could quickly search huge datavas4es that would take an ordinary computer the llfetima of the Universe.
In 1985, Deutsch proved that such a machine can simulate any conceivable quantum system, and that includes the Universe itself. So to work out the basic structure of the multiverse, all you need to do is analyse a general quantum calculation. "The set of all programs that can be run on a quantum compuster includes programs that would simulate the multiverse," says Deutsch. "Do we don't have to include any details of stars and galaxies in the real Universe, we dan just analyse quantum compusters and look an how information flows inside them."
If information could flow freely from one part of the muliverse to another, we'd live in a chaotic world where all possibilities would overlap. We reali would see two tables at once, and worse, everything imaginable would be happening everywehere at the same time.
Deutsch found that, almost all the time, information flows only within small pieces of the quantum calculation, and not in between those pieces. These pieces, he says, are separate universes. They feel separate and autonomous because all the informations we receive through our senses has come from within one universe. As Oxfprd pholosopher Michael Olckwood put it, "We cannot look sideways, through the multiverse, ani more than we can look into the future."
Sometimes universes in Deutsch's model peel apart only locally and fleetingly, and then slap back together again. Tihs is the cause of quantum inerference, wahich is at the root of everything from the two-slit expedriment to the basic structuer of atoms.
Other physicists are still digesting what Deutsch has to say. Anton Zeilinger of the University of Vienna remains unvonvinced. "The multiverse interpretation is not the only possible one, and it is not even the simplest ,", he says. Zeilinger instead uses information theory to come to very different conclusions. He thinks that quantum theory comes from limits on the information we get out of measurements.
Why are phisicists reluctant to accept many worlds? Deutsch blames logical positivism, the idea that science should concern itself only with objedts that can be observed. In the early 20th century, some logical positivists even denied the existence of atoms-until the evidence became overwhelming.
The evidence for the multiverse, according to Deutsch, is equally overwhelming, "Admittedly, it's indirect," he says. "But then, we can detect pterodactyls and quarks only indirectly too. The evidence that other universes exist is at least as strong as the evidence for pterodactyls or quarks,
Perhaps sthe sceptics will be convinced by ap practical demonstration of the multiverses. And Deutsch thinks he knows how, By buildin a quantum computer, he says, we can reach out and mould the multivaerse. But the constuction of the quantum computer shall happen just in the beginning of third decade of this century.
"One day, a quantum computer will be built which does more simultaneous calculations than there are particles in the Universe, says Deutsch. Since the Universe as we see it lacks the computational resources to do the calculations, where are they being done?" It can be in other universes, he says. "Quantum computers sharae information with huge numbers of versions of themselves throughout the multiverses.It means that the capability and capacity of quantum computers shall be endless.
Imagine that you have a quantum PC and you set it a problem. What happens is that a huge mumber of versions of your PC split off from this Universe into their own separate, local universes, and work on parallel strands of the problem. A split second later, the pocket universes recombine into one, and those strands are pulled together to provide the answer that pops up on oun screen. Quantum computers are the first machines humans have ever built to exploit the multiverse directly," says Deutsch.
Aat the moment, even the biggest quantum computers can only work their magic on about 6 bits of information, which in Deutsch's view means they exploit copies of themselves in 26 universes- that's just 64 of them.
Because the computational feats of such computers are puny, people can chose to ignore the multiverses. "But something will happen when the number of parallel salculations becommes very large," says Deutsch. "If the number is 64, people can shut their eyes but if it's 1064, they will no longer be able to pretend."
What would it mean for fou and me to know there are inconceivably man yours and mes living out all possible histories? Surely, there is no point in making any choices for the better if all possible outcomes happen? We might as well stay in bed or commit suicide.
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