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Topic: No cloning theorem

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  No cloning theorem -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-10-06)
The no cloning theorem is a result of (The branch of quantum physics that accounts for matter at the atomic level; an extension of statistical mechanics based on quantum theory (especially the Pauli exclusion principle)) quantum mechanics which forbids the creation of identical copies of an arbitrary unknown quantum state.
In contrast, the no cloning theorem is a vital ingredient in (Click link for more info and facts about quantum cryptography) quantum cryptography, as it forbids eavesdroppers from creating copies of a transmitted quantum cryptographic key.
Imperfect cloning can be used as an eavesdropping attack on quantum cryptography protocols, among other uses in quantum information science.
www.absoluteastronomy.com /encyclopedia/n/no/no_cloning_theorem.htm   (991 words)

 No cloning theorem - Wikipedia, the free encyclopedia
The no cloning theorem is a result of quantum mechanics which forbids the creation of identical copies of an arbitrary unknown quantum state.
The no cloning theorem prevents us from using classical error correction techniques on quantum states.
In contrast, the no cloning theorem is a vital ingredient in quantum cryptography, as it forbids eavesdroppers from creating copies of a transmitted quantum cryptographic key.
en.wikipedia.org /wiki/No-cloning_theorem   (676 words)

 54 No cloning theorem for contionous variables   (Site not responding. Last check: 2007-10-06)
However, there is no serious attempt to formulate the ``no-cloning'' theorem for quantum systems with continuous variables.
In this talk, I will present the ``no-cloning'' theorem for continuous variables, and show that even though two orthogonal states can be cloned perfectly for discrete quantum systems the same cannot be done for a continuous quantum system.
The cloning of two non-orthogonal wave functions is discussed and the errors introduced by copying procedure is obtained.
optics.szfki.kfki.hu /cewqo2000/BA/node55.html   (371 words)

 Physics bans cloning
But quantum cloning is only feasible if one accepts a little bit of copying error - as two US physicists proved in 1982 with their 'no-cloning' theorem.
This theorem means that quantum teleportation - recreating a quantum particle in a different location from the original, but in exactly the same state - is only possible if the original is destroyed, so that it does not coexist with its copy.
No one had given much thought to ideas such as exact cloning and teleportation on macroscopic scales, where Newton's laws of classical physics apply.
www.freerepublic.com /focus/chat/695243/posts   (631 words)

 Talk:Uncertainty principle - Wikipedia, the free encyclopedia
Disturbance plays no part since the principle even applies if position is measured in one copy of the system and momentum is measured in another, identical one.
The PEP is a theorem in the relativistic formulation.
There is a theorem relating the "uncertainty" in a function and the uncertainty in its Fourier transform.
en.wikipedia.org /wiki/Talk:Uncertainty_Principle   (5276 words)

 Quantum Information: Basic Concepts
In the theory of Quantum Information entanglement is no longer viewed merely as a means to "subtly humiliate the opponents of quantum mechanics" (C.H. Bennett), but as a resource needed to perform otherwise impossible tasks of information processing or computation.
The term "cloning" in the quantum context, coined in a short paper by Wooters and Zurek [WZ82], reflects rather well the idea that there is no blueprint for quantum systems (analogous to a sheep's DNA) from which all its properties could be derived (see the remarks on teleportation).
All these limit relations are in agreement with the intuition that state estimation is the limit of cloning as the number of clones goes to infinity, and that this limit is very closely related to the classical limit.
www.imaph.tu-bs.de /qi/concepts.html   (3109 words)

 Nanotech Alert   (Site not responding. Last check: 2007-10-06)
An operation to clone or delete a state only works for a preferred set of mutually exclusive quantum states such as 0 or 1.
You would need a mechanism that takes two photons in the same initial polarization state and produces one photon in the same initial state and another in some standard polarization state.
No one can obliterate a copy of an unknown file from a collection of several copies.
www-users.cs.york.ac.uk /~schmuel/news98/nanotech.html   (482 words)

 Physics Help and Math Help - Physics Forums - View Single Post - The Quantum Tunneling Teleporter
In fact the "no cloning" theorem of physics proves it.
But by definition it would be the same person, even more identical than if the person had taken a spaceship to the moon, since undoubtedly the person would have noticeably changed from the time they left the Earth and arrived on the moon.
Of course the problem with this idea of teleportation is no process is ever going to be 100% efficient.
www.physicsforums.com /showpost.php?p=407720&postcount=2   (558 words)

 Innsbruck Lectures   (Site not responding. Last check: 2007-10-06)
I prove a "data processing" inequality for distinguishability; Holevo's theorem follows as a corollary given a physical model of measurement.
Also included are two diagrams (1 and 2) of outlining Lloyd's argument that up to I qubits of entanglement can be sent through a noisy quantum channel with fidelity approaching unity.
I discuss three applications of the ideas developed in lectures 1-6: approximate quantum cloning, privacy in quantum cryptography, and the relation of decoherence to the loss of coherent information in a quantum system.
www2.kenyon.edu /People/schumacb/Innsbruck/lectures.htm   (452 words)

 Illustrating the concept of quantum information
First we revisit the quantum no-cloning theorem [3] and prove a new stronger form of this result.
To prove the theorem we use the following lemma, which is proved as Lemma 1 of [7].
This was realized soon after the appearance of Schumacher's compression theorem and discussed by Bennett and other participants during the first ELSAG–Bailey Quantum Computation Workshop at the Institute for Scientific Interchange in Torino, Italy, in July 1993 (subsequently leading to [11]).
www.research.ibm.com /journal/rd/481/jozsa.html   (3851 words)

 [extropy-chat] Encryption revolution   (Site not responding. Last check: 2007-10-06)
That is because there is a no-cloning (and a stronger no-cloning) theorem and also a no-deleting (and a stronger no-deleting) theorem.
http://www-users.cs.york.ac.uk/~schmuel/papers/pb00.pdf http://www.research.ibm.com/journal/rd/481/jozsa.pdf The above theorems are connected to the possibility of FTL signals http://arxiv.org/abs/quant-ph/0305145 and perhaps also to a possible general principle of conservation of quantum information.
http://arxiv.org/abs/quant-ph/0306044 Classical information is physical but has no "permanence", that is to say it can be cloned, deleted, and of course erased.
lists.extropy.org /pipermail/extropy-chat/2003-December/001832.html   (139 words)

 [No title]
The no-cloning theorem states that for an arbitrary qubit, it is impossible to perform an unitary operation which duplicates the qubit.
The k bits are treated as a vector and represented by a matrix,  EMBED Equation.3  The generator matrix G then encodes this matrix and the result is G*X = V. The encoded message is then transmitted and the original data map and the transmitted data map are compared.
To check which bit was hit by the error, the parity check matrix H is multiplied by V. If there was no error on transmission, the resulting matrix will be a 0, else it will be the binary equivalent of the index of the bit in V where there was an error.
people.clarkson.edu /~gangulys/Introduction.doc   (5321 words)

 discuss@bloom-picayune: [14239] in cryptography@c2.net mail archive
The physical limit for cloning is 5/6ths of the bits will > clone true.
It may just be an artifact of the particular unitary transform used in that specific cloning process.
The no-cloning theorem per se doesn't disallow these, it only disallows perfect cloning, but other physics might.
diswww.mit.edu /bloom-picayune/crypto/14239   (345 words)

 [extropy-chat] Why no assembler design?   (Site not responding. Last check: 2007-10-06)
We question the existence of a universal constructor that may allow for the self-replication of an arbitrary quantum system.
We prove that there is no deterministic universal quantum constructor which can operate with finite resources.
Further, we delineate conditions under which such a universal constructor can be designed to operate dterministically and probabilistically.
lists.extropy.org /pipermail/extropy-chat/2003-November/000972.html   (311 words)

 Photons get the quantum cloning treatment (March 2002) - News - PhysicsWeb
Quantum systems cannot be cloned – or duplicated – perfectly, but the development of quantum cryptography and computing relies on a knowledge of exactly how well they can be copied.
This is the ‘no-cloning’ theorem, which is the basis of quantum cryptography.
In earlier experiments, physicists at Oxford cloned large assemblies of quantum systems (arXiv.org/abs/quant-ph/0111098), and a group at the University of Science and Technology of China imprinted the polarization and the motion of a single photon onto two clones (Phys.
physicsweb.org /article/news/6/3/21/1   (587 words)

 ipedia.com: No cloning theorem Article   (Site not responding. Last check: 2007-10-06)
, of which we have no prior knowledge.) The composite system is then described by the tensor product, and its state is
While a unitary operator which describes cloning of an arbitrary unknown quantum state into a given state as the evolution is not linear, according to the proof stated above, it is perhaps worth noting that an appropriate such unitary operator nevertheless is nonlinear.
Buzek, V. and Hillery, M. : "Quantum cloning".
www.ipedia.com /no_cloning_theorem.html   (701 words)

 Optimal Cloning of Pure States - Werner (ResearchIndex)   (Site not responding. Last check: 2007-10-06)
We construct the unique optimal quantum device for turning a finite number of d-level quantum systems in the same unknown pure state oe into M systems of the same kind, in an approximation of the M-fold tensor product of the state oe.
1 Optimal universal cloning and state estimation (context) - Bruss, Ekert et al.
1 Quantum cloning, eavesdropping and Bell's inequality (context) - Gisin, Huttner - 1997
citeseer.ist.psu.edu /werner98optimal.html   (556 words)

 Cloning   (Site not responding. Last check: 2007-10-06)
against cloning at all, so most of my suggestions will be for other ways.
I was wondering if some analog of the no cloning theorem obviously holds
cloning techniques, laws, research trends, and the reasons people want to be cloned.
therapeuticcloning.ca /index.php?C=+Cloning&T=0   (248 words)

 Destiny Matrix
What prevents signal nonlocality and enforces the "no-cloning theorem" is the linearity, the probability interpretation, and the unitary time evolution in orthodox quantum theory.
There is no "collapse" in Bohmian quantum theory nor in the emergent macro-quantum theory of local order parameters in both the "off-shell" physical vacuum (for gravity) and in the "on-shell" brain of higher organisms.
No continuous deformation of the magnetization, keeping the magnitude constant" (decoherence-proof generalized phase rigidity, e.g.
www.destinymatrix.blogspot.com   (16115 words)

 Résumé 14 janvier 2003   (Site not responding. Last check: 2007-10-06)
The Quantum Injected Optical Parametric Amplifier (QIOPA) has been adopted to create an all optical Schroedinger Cat (S-Cat) set in the "universality" condition, i.e.
The optical S-Cat condition is critically investigated in the view of the efficiency of the possible decoherence channels and, more fundamentally, of several processes which are forbidden by the laws of quantum mechanics, e.g.
of the No-cloning theorem and of the impossibility of any universal U-Not quantum gate.
www.lkb.ens.fr /seminaires/resu060503.html   (113 words)

 Superbroadcasting   (Site not responding. Last check: 2007-10-06)
Later, in the literature this result has been often implicitly considered as the generalization of the no-cloning theorem to the case of mixed input states, according to the general statement that an arbitrary pair of states can be broadcast if and only if they are represented by mutually commuting density matrices
For pure states the optimal superbroadcasting map is the same as the optimal universal cloning [R. Werner, Phys.
The possibility of superbroadcasting does not correspond to an increase of the available information about the original input state, due to detrimental correlations between the broadcast copies, which does not allow to exploit their statistics [this phenomenon was already noticed by M. Keyl and R. Werner, Ann.
www.quantummechanics.it /research/results/superbroadcasting.html   (260 words)

 Points from my Honours Thesis   (Site not responding. Last check: 2007-10-06)
There are lots of surprising correspondences between functional programming and quantum computing: uniqueness types (a concept designed to assist garbage collection) very neatly map onto the no-cloning theorem.
In the Qgol evaluator, I declared the abstract *Quantum type to be unique, and could be assured of physical logic being preserved as a result.
I created a formalism for describing quantum computation; as far as I could see, there is no meaning to the term "universal quantum computer", but apparently there were quite a few problems with what I wrote!
www.ifost.org.au /~gregb/q-gol/thesis-points.html   (343 words)

 Stardrive.org - - Article/Content Template   (Site not responding. Last check: 2007-10-06)
The no-cloning theorem is the corner stone of the IBM vaporware field of
The no-cloning theorem is thought to prevent the use of quantum nonlocality
No part of this book may be reproduced, stored in a retrieval system, or
www.stardrive.org /Sarmail1-2-02.shtml   (12753 words)

 A General No-cloning Theorem (ResearchIndex)   (Site not responding. Last check: 2007-10-06)
Abstract: A simple theorem is proved which has most of the known no-cloning and no-broadcasting results as corollaries.
It also implies the standard restrictions on measuring non-commuting observables.
This says that there is no way of constructing an apparatus capable of accepting a general quantum state as input, and as output giving back the original state plus a...
citeseer.ist.psu.edu /lindblad98general.html   (267 words)

 Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations   (Site not responding. Last check: 2007-10-06)
Energy Citations Database (ECD) Document #383122 - Quantum copying: Beyond the no-cloning theorem
Availability information may be found in the Availability, Publisher, Research Organization, Resource Relation and/or Author (affiliation information) fields and/or via the "Full-text Availability" link.
We analyze the possibility of copying (that is, cloning) arbitrary states of a quantum-mechanical spin-1/2 system.
www.osti.gov /energycitations/product.biblio.jsp?osti_id=383122   (201 words)

 Friday, April 28, a.m. Room 46   (Site not responding. Last check: 2007-10-06)
Quantum Cryptography and No-Cloning Theorem for Pure, Mixed, and Entangled States
Koashi, N. Imoto, The Graduate University for Advanced Studies, Ilayama, Kanagawa, Japan
Last modified: Mon Mar 6 18:13:59 MET 2000
www.osgk.ac.at /emcsr/00/FriAM46.html   (69 words)

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