Fast Quantum Byzantine Agreement: Difference between revisions

Fast Quantum Byzantine Agreement (edit)

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Revision as of 18:33, 17 April 2019 (edit) Shraddha (talk \| contribs) (Created page with " This protocol achieves the functionality of Quantum Cloning. Asymmetric universal cloning refers to a quantum cloning machine (QCM) where its output clones are not the sa...")		Revision as of 18:35, 17 April 2019 (edit) (undo) Shraddha (talk \| contribs) No edit summary Newer edit →
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	~~This protocol achieves the functionality~~ of ~~[[Quantum Cloning]]~~. ~~Asymmetric universal cloning refers~~ to ~~a quantum cloning machine (QCM) where its~~ output ~~clones are not~~ the same ~~or in other words~~, ~~they have different [[fidelities]]. Here we focus on~~ <math>~~1 \rightarrow 1 + 1~~</math> ~~universal cloning~~. ~~In asymmetric cloning, we try to distribute information unequally among~~ the ~~copies~~. ~~A trade-off relation exists between the fidelities~~, ~~meaning if one of~~ the ~~copies~~ are ~~very close~~ to the ~~original state, the other one will be far from it~~. ~~There are two approaches to~~ this ~~kind of cloning~~, ~~both leading~~ to ~~same trade-off relation. Here we discuss the quantum circuit approach (Buzek et al~~., 1997) It can be also noted that the symmetric universal <math>1 \rightarrow 2</math> cloning can be considered as a special case of the asymmetric universal cloning where the information between copies has been equally distributed.		The classical problem of Byzantine agreement\cite{Lamport1982} is about reaching agreement in a network of $n$ players out of which <math>t</math> players may be faulty. Each player starts with an input bit <math>b_i</math> and the goal is for all correct players to output the same bit <math>d</math> (\emph{agreement}), under the constraint that <math>d = b_i</math> at least for some node <math>i</math> (\emph{validity}). The hardness of this task depends on the failure model of the faulty (sometimes called adversary) players. In Byzantine agreement, the faulty players are assumed to show the most severe form of failure known as Byzantine failures. In this model, faulty players behave arbitrarily, can collude and even act maliciously trying to prevent correct players from reaching agreement. Byzantine agreement is an important problem in classical distributed systems, used to guarantee consistency amongst distributed data structures.

	'''Tags:''' [[Category: Building Blocks]][[:Category: Building Blocks\|Building Blocks]], [[Quantum Cloning]], Universal Cloning, asymmetric cloning, copying quantum states, [[:Category: Quantum Functionality\|Quantum Functionality]][[Category: Quantum Functionality]], [[:Category:Specific Task\|Specific Task]][[Category:Specific Task]],symmetric or [[Optimal Universal N-M Cloning\|Optimal or Symmetric Cloning]], [[Probabilistic Cloning]]		'''Tags:''' [[Category: Building Blocks]][[:Category: Building Blocks\|Building Blocks]], [[Quantum Cloning]], Universal Cloning, asymmetric cloning, copying quantum states, [[:Category: Quantum Functionality\|Quantum Functionality]][[Category: Quantum Functionality]], [[:Category:Specific Task\|Specific Task]][[Category:Specific Task]],symmetric or [[Optimal Universal N-M Cloning\|Optimal or Symmetric Cloning]], [[Probabilistic Cloning]]