Re: Quantum computing and the future of cryptography

I see that You believe that practically the only real algorithmic
advantage of QC is the Shor's algorithm.
Probably You are right, but ... QC can theoretically make all
calculations at once (is almost nondeterministic Turing machine) and
the only problem is with the extraction. I'll show how to enhance it,
but it would be strange if basic QC wouldn't already allow for more,
maybe even solving NP in polynomial time. Especially that if someone
would find a way, he could not necessary tell it loud, but for example
try to became rich...

The next argument that we should take such scenarios seriously is that
maybe basic QC is not the only possibility for massive parallel
computation physics gives us. First of all there is so called Feynman-
Stueckelberg effect
http://groups.google.com/group/sci.physics.research/browse_thread/thread/9d10b4e5cbda1108
which hasn't been taken seriously, but maybe it will change in a few
months in LHC ... but such computer would require (huge?) accelerator.

The other option can be (quantum) loop computers
http://groups.google.com/group/sci.crypt/browse_thread/thread/736fd9f3e62132c2
I'm strongly confused about this idea, especially for classical
computers.
But ... if used for quantum computation, such feedback should amplify
the correct solution (wavefunction), making the rest of them vanish.
It couldn't be standard approach to QC in which we use some sequence
of for example external fields on some lattice of atoms.
We would need a circuit which allows to sustain entanglement of many
calculations.
Observe that similarly to benzene, (-CH=CH-) sequence can be in
quantum superposition with shifted one (=CH-CH=) - we could use such
molecule as a wire for qbits. Unfortunately it has some resistance,
but there are know such superconductors also.
We know also transistors made of single molecule - they are
irreversible so would destroy entanglement, but there should be
possible also quantum gates made this way.
The question is if such molecular quantum computers could sustain
entanglement for practically long time ... There is also problem with
auxiliary variables - we need a lot of them because in QC all
calculations has to be reversible. They cannot be sent in the loop -
they should be treated in some special way to not destroy the
entanglement ... but maybe ?

Probably physics doesn't allow to solve NP in polynomial time, but I'm
far from being sure of it.
.

Relevant Pages

  • Re: Quantum computing and the future of cryptography
    ... The other option can be loop computers ... if used for quantum computation, ... We would need a circuit which allows to sustain entanglement of many ... We know also transistors made of single molecule - they are ...
    (sci.crypt)
  • Re: Quantum computing and the future of cryptography
    ... The other option can be loop computers ... if used for quantum computation, ... We would need a circuit which allows to sustain entanglement of many ... We know also transistors made of single molecule - they are ...
    (sci.crypt)
  • What field to study
    ... I am a college student and I am very interested in quantum computers ... and information theory and entanglement and algorithms that can be used ... by these future computers. ...
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