**Others Are Catching On!**
Check out this paper (emphases included are mine). John Titor claimed to be a time traveler who was telling you about our future, which is of course hogwash. I am an engineer who dabbles in the theoretical sciences. I don't claim to be a time traveler, nor make any other wild, unbelievable claims. And yet I am telling you about how our past and present are leading to a VERY clear view of what our future will become! And unlike John Titor, I won't "run away" from the predictions I am laying out in these posts.

RMT

> "Nature Physics 1, 2-4 (2005)

> doi:10.1038/nphys134

>

**Is information the key?**
> Gilles Brassard1

> 0.Gilles Brassard is in the Dpartement d'informatique et de

> recherche oprationnelle, Universit de Montral, Qubec H3C

> 3J7, Canada. e-mail:

brassard@iro.umontreal.ca
>

> Abstract

**> Quantum information science has brought us novel means of **
**> calculation and communication. But could its theorems hold the key**
**> to understanding the quantum world at its most profound level? Do **
**> the truly fundamental laws of nature concern â€” not waves and **
**> particles â€” but information?**
>

> Imagine, what if all of quantum mechanics could be derived simply

> by taking those two quantum cryptographic theorems as axioms?

>

> This year marks the centenary of quantum mechanics. Despite earlier

> work by Max Planck, it was Albert Einstein's Nobel prize-winning

> 1905 paper 1 on the photoelectric effect that gave us what is

> arguably the greatest scientific theory of all time. Subsequently,

> the stones that make up the exquisite structure of quantum

> mechanics were laid out, one by one, by a stream of legendary

> giants such as Niels Bohr, Erwin SchrÃ¶dinger and Werner

> Heisenberg â€” sometimes to the horror of Einstein. An almost

> inevitable consequence of this collective foundational effort over

> so many years is that quantum mechanics, for all its elegance, is

> built upon a rather disjointed, ad hoc set of axioms.

>

> Quantum mechanics has forced us to rethink the nature of the

> physical world, its teachings often running counter to our

> misleading macroscopic experience. It is time to pause and reflect

> on what we've learned in the course of these 100 years. Alongside

> Christopher Fuchs 2, I contend that there is a fresh perspective to

> be taken on the axioms of quantum mechanics that could yield a more

> satisfactory foundation for the theory.

>

> New horizons

> Quantum mechanics has changed our outlook on the world. The

> transistor, the laser, superconductivity, the atomic bomb â€” these

> early applications of the theory are but a few among those that

> have reshaped the way we live. The transistor made possible a

> dramatic increase in computation speed. However, given enough time,

> cog-and-wheels devices such as Charles Babbage's analytical engine

> are, in principle, capable of the same calculations. In a very real

> sense, the modern electronic computer is essentially a classical

> device. Could genuinely quantum-mechanical effects be harnessed for

> computing purposes?

>

> In the early 1980s, it occurred to Richard Feynman 3 and David

> Deutsch 4 that a quantum computer could become so efficient that it

> would far outperform its classical counterpart. For example, an

> atom can be simultaneously in its ground and excited states. If we

> assign classical bit 0 to one state and bit 1 to the other (Fig.

> 1), this gives us a quantum bit, or qubit. If we string together

> ten qubits, they can be collectively in all 1024 classical states

> of ten bits, and we can compute using all those states in parallel.

> If we replace those ten qubits by one thousand, we obtain 2^1,000

> (roughly 10^301) simultaneous operations. This entails an amount of

> parallelism that could not be matched by a classical computer the

> size of the Universe, in which each elementary particle would be

> harnessed as a processing unit.

>

> Figure 1 - Assign classical bits 0 and 1 to, for example, the

> ground and excited states of an atom, and the power of quantum

> computation is unleashed.

>

> But, even if the quantum computer existed, could it perform

> calculations that are impossible in the classical world?

>

> Quantum computing was at first regarded as a mere theoretical

> concept, but interest in it grew when Peter Shor discovered a way

> to use its capabilities to factorize large numbers efficiently 5.

> Such a computer would threaten the public-key cryptographic schemes

> currently in use, in particular for the secure transmission of

> credit card numbers over the Internet. Electronic commerce in its

> current form is saved from a catastrophic collapse only because the

> construction of a full-size quantum computer is, for the moment,

> eluding our technological capabilities. And we can only shiver to

> think of the effect that such a collapse of classical cryptography

> could have on national security. Even though the potential of

> quantum computers is mind-boggling, that does not change the

> theoretical notion of what is computable. The mathematical theory

> of computability is rooted in the 1936 groundbreaking work of Alan

> Turing 6. According to this theory, a problem is deemed to be

> computable if an algorithm can solve it, no matter how long it

> would take â€” even, indeed, should it take longer than the lifetime

> of the Universe. From this perspective, quantum computers can only

> solve problems that are already classically computable.

>

> Enter cryptography

> This begs the question: are there information-processing tasks that

> are impossible even in principle in the classical world, but that

> become possible through quantum mechanics? Even though unpublished

> for nearly fifteen years, the answer came to Stephen Wiesner well

> before anyone had thought of quantum computing. Around 1970, he

> discovered that quantum-mechanical effects could be used to produce

> banknotes that would be impossible to counterfeit 7. Because

> quantum information cannot be cloned, Wiesner realized that a

> banknote that contained quantum information would be impossible to

> copy. Unfortunately, this revolutionary (albeit impractical) idea

> went completely unnoticed, except by Wiesner's former undergraduate

> classmate Charles H. Bennett.

>

> Almost a decade elapsed before Bennett told me of Wiesner's idea,

> which led to our joint invention of quantum cryptography 8, 9. For

> ages, mathematicians had searched for a system that would allow two

> people to exchange messages in absolute secrecy. In the 1940s,

> Claude Shannon proved that this goal is impossible unless the two

> communicating parties share a random secret key that is as long as

> the message they want to communicate 10; moreover, that secret key

> can be used once only. In quantum cryptography, however, this

> pessimistic theorem can be thwarted by exploiting both the

> impossibility of measuring quantum information reliably and the

> unavoidable disturbance caused by such measurements. When

> information is appropriately encoded as quantum states, any attempt

> by an eavesdropper to access it necessarily entails a probability

> of spoiling it irreversibly. This disturbance can be detected by

> the legitimate users, allowing them to establish an unconditionally

> secure confidential channel with no need for a shared secret key.

> After we reported 11 the first experimental realization of quantum

> cryptography, Deutsch wrote 12 in New Scientist: "Alan Turing's

> theoretical model is the basis of all computers. Now, for the first

> time, its capabilities have been exceeded." It is interesting to

> note that quantum computers threaten most of the classical

> cryptographic schemes in use today, but that quantum cryptography

> offers an unconditionally secure alternative."

>

> Only if the perfect no-cloning theorem prevents "signal

> nonlocality" as defined in papers by Antony Valentini now at the

> Perimeter Institute. If micro-quantum theory is to macro-quantum

> theory (with hidden symmetries in the ground state of large

> systems) as special relativity is to general relativity, then the

> "unconditionally secure alternative" could be the "Maginot Line" of

> the National Security Corporate State. The Fat Lady has not sung on

> this yet and policy wonks in USG Intelligence should not be lulled

> into a false sense of security by the above kinds of statements.

>

> "The most obvious goal of cryptography always has been the secure

> transmission of confidential information, but the past three

> decades have seen the rise of a host of novel applications for

> cryptographic techniques, such as digital signatures and secure

> multiparty computation. However, all these classical concepts are

> obviously defeated if cheaters are allowed unlimited computing

> power. Moreover, most of their proposed implementations fall prey

> to quantum computing attacks 5. After the success of quantum

> cryptography in confidential communication, it was natural to hope

> that quantum techniques could also assist in designing

> unconditionally secure protocols for these more sophisticated tasks.

>

> One of the simplest tasks is known as 'bit commitment' â€” a rather

> abstract concept but a crucial stepping-stone to achieving more

> impressive cryptographic goals. In a bit-commitment scheme, one

> party (Alice) commits to a bit by sending something to the other

> party (Bob). Later, Alice can unveil the commitment, thereby

> letting Bob know to which bit she had committed. The scheme is

> 'concealing' if it's impossible for Bob to learn anything about the

> committed bit simply by analysing what Alice sent him when she

> committed; it is 'binding' if it's impossible for Alice to delay

> until unveiling the choice of bit she wants to show Bob.

>

> For many years, the design of an unconditionally concealing and

> binding protocol to implement bit commitment by quantum means was

> considered the key to unlock almost everything we may wish to do

> with cryptography. Unfortunately, it was proven â€” independently by

> Dominic Mayers13 and by Hoi-Kwong Lo and Hoi Fung Chau 14 â€” that

> such quantum schemes are impossible.

>

> A fresh perspective

> Quantum mechanics can help cryptography, but only up to a point: it

> does allow unconditionally secure transmission of confidential

> information, but not unconditionally secure bit commitment. These

> two facts are generally considered to be deep theorems of modern

> quantum information science. But do their implications reach beyond

> information science? What might they tell us about the wider

> physical world?

>

> Fuchs â€” the prime mover in this intellectual venture â€” has gone

> so far as to suggest that the first of these theorems (the

> possibility of perfect confidentiality), or perhaps others of a

> similar informational flavour, could serve as the basis of a new

> foundation for quantum mechanics, in which information takes centre

> stage. Inspired by the fascinating discussions I had had with

> Fuchs, it occurred to me that the second theorem (the impossibility

> of bit commitment) could be just as fundamental 15. Imagine, what

> if all of quantum mechanics could be derived simply by taking those

> two quantum cryptographic theorems as axioms?

>

> Admittedly, in its original form this idea was trashed by John

> Smolin, who devised an artificial world in which unconditional

> confidentiality was possible but not bit commitment, and his world

> was anything but a quantum one 16. But discussions with Jeffrey Bub

> breathed new life into Fuchs' and my dream. With Rob Clifton and

> Hans Halvorson, he chose to pull away somewhat from cryptography

> and declare more fundamental properties of quantum information as

> their axioms: the fact that no manipulations taking place at some

> point in space can have an instantaneously observable effect at

> some remote other point (the 'no-signalling property'); and that

> information cannot be cloned."

>

> Don't be so sure. However, one can see that factual violation of

> the 'no-signalling property" brings the whole quantum cryptography

> program down like an unstable house of cards. Quantum security

> rests on shaky ground that could turn into quicksand.

>

> "This pair replaced the axiom that transmitting information with

> unconditional confidentiality is possible, and they kept the axiom

> that unconditionally secure bit commitment is impossible.

>

> To derive anything from these information-theoretic essentials,

> they had to assume that the laws of physics can be formalized in

> the framework of mathematical tools known as C*-algebras. But it is

> amazing where their axioms took them: they were able to derive

> basic kinematic features of quantum mechanics, such as the

> principle of interference, the non-commutativity of measurements

> and the existence of space-like separated entanglement 17. A

> fascinating feature in their approach is that the impossibility of

> bit commitment is used to prove not only that entanglement exists,

> but that it must survive indefinitely across time and space â€”

> which is indeed the single most non-classical property of quantum

> mechanics.

>

> These are only the first steps, but could we eventually base

> quantum mechanics on information-theory axioms alone, without the

> need for specific assumptions about the physical theory (such as

> the use of C*-algebras)? Could we infer more about quantum

> mechanics than purely the kinematic properties mentioned above?

> Which other theorems of quantum information science might make

> powerful axioms for quantum mechanics when we turn the table round?

>

> On that last point, I have a suggestion. Consider the field of

> communication complexity, which concerns the amount of information

> that must be transmitted between two parties to compute some

> function of private inputs that they hold. It turns out that the

> required transfer can be reduced dramatically in some cases when

> the parties share prior entanglement 18. Nevertheless, even in the

> presence of unlimited shared entanglement, some boolean functions

> require a number of bits of communication that grows linearly with

> the input size.

>

> It was discovered by Wim van Dam 19, and independently by Richard

> Cleve, that all boolean functions could be computed with a single

> bit of communication, should physics allow a certain form of non-

> local correlation even stronger than those provided by quantum

> entanglement. What makes this discovery so interesting is that

> those super-quantum correlations do not violate the no-signalling

> property 20. In other words, quantum mechanics exhibits non-local

> properties within the framework of Einstein's causality â€” but not

> as strongly as it could.

>

> Once again we should ask what all of this is trying to tell us

> about nature. I suggest that this could be another axiom: it is not

> possible to compute all bipartite boolean functions with a single

> bit of communication. How much more of quantum mechanics might be

> derived from it?

>

**> A century after Einstein's annus mirabilis, quantum information**
**> science could turn out to be much more than just an application of**
**> quantum theory. It could define its very nature."**
>

>

> References

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