Incomparability of pure bipartite entangled states under deterministic LOCC is a very strange phenomena. We find two possible ways of getting our desired pure entangled state which is incomparable with the given input state, by collective LOCC with certainty. The first one is by providing some pure entanglement through the lower dimensional maximally-entangled states or using further less amount of entanglement and the next one is by collective operation on two pairs which are individually incomparable. It is quite surprising that we are able to achieve maximally entangled states of any Schmidt rank from a finite number of 2x2 pure entangled states only by deterministic LOCC. We provide general theory for the case of 3x3 system of incomparable states by the above processes where incomparability seems to be the most hardest one.Incomparability of pure bipartite entangled states under deterministic LOCC is a very strange phenomena. We find two possible ways of getting our desired pure entangled state which is incomparable with the given input state, by collective LOCC with certainty. The first one is by providing some pure entanglement through the lower dimensional maximally-entangled states or using further less amount of entanglement and the next one is by collective operation on two pairs which are individually incomparable. It is quite surprising that we are able to achieve maximally entangled states of any Schmidt rank from a finite number of 2x2 pure entangled states only by deterministic LOCC. We provide general theory for the case of 3x3 system of incomparable states by the above processes where incomparability seems to be the most hardest one.

arXiv:quant-ph/0409174Quantum Information and ComputationMay 1, 20054 citations

Entanglement - A Queer In The World Of Quantum : Some Perspectives

Indrani Chattopadhyay

The work is intended to represent some interesting and apparently peculiar features of entangled system in both pure as well as mixed states level. In the pure state level, we are largely concerned about the existence and characteristics of bipartite incomparable pair of states. We have found some schemes for local transformation of one pure bipartite state to another, incomparable in nature, by exploiting free unpreserved entanglement. Also, we observed that different incomparable pair of states in $3\times 3$ may co-operate with each other to cross the barrier of incomparability. Our next goal was to probe critically the roots of the existence of incomparable states. We have succeeded in connecting incomparability with some famous no-go theorems of quantum mechanics. We have established it with no-flipping principle, general anti-unitary operators and lastly with inner product preserving operations. Thus we are able to pose incomparability as a good detector of some non-physical operations. In the next part, we provide a new class of multipartite bound entanglement in mixed state level. The class of states are activable bound entangled. There are exactly four orthogonal activable bound entangled states in any even number of qubit system. They have some interesting features like Bell correlation, permutation symmetry, local Pauli connection, non-compatibility, etc. Apart from those properties, the class of bound entangled states have the remarkable feature of local indistinguishability in quantum systems.The work is intended to represent some interesting and apparently peculiar features of entangled system in both pure as well as mixed states level. In the pure state level, we are largely concerned about the existence and characteristics of bipartite incomparable pair of states. We have found some schemes for local transformation of one pure bipartite state to another, incomparable in nature, by exploiting free unpreserved entanglement. Also, we observed that different incomparable pair of states in $3\times 3$ may co-operate with each other to cross the barrier of incomparability. Our next goal was to probe critically the roots of the existence of incomparable states. We have succeeded in connecting incomparability with some famous no-go theorems of quantum mechanics. We have established it with no-flipping principle, general anti-unitary operators and lastly with inner product preserving operations. Thus we are able to pose incomparability as a good detector of some non-physical operations. In the next part, we provide a new class of multipartite bound entanglement in mixed state level. The class of states are activable bound entangled. There are exactly four orthogonal activable bound entangled states in any even number of qubit system. They have some interesting features like Bell correlation, permutation symmetry, local Pauli connection, non-compatibility, etc. Apart from those properties, the class of bound entangled states have the remarkable feature of local indistinguishability in quantum systems.

arXiv:0805.2056May 14, 20080 citations

Entanglement of Pure States

Stig Stenholm

Foundations of PhysicsJan 26, 20090 citations

27aYN-12 Remote quantum operations and entanglement

美緒村尾, Vlatko Vedral

日本物理学会講演概要集Mar 9, 20010 citations

3\times 3

may co-operate with each other to cross the barrier of incomparability. Our next goal was to probe critically the roots of the existence of incomparable states. We have succeeded in connecting incomparability with some famous no-go theorems of quantum mechanics. We have established it with no-flipping principle, general anti-unitary operators and lastly with inner product preserving operations. Thus we are able to pose incomparability as a good detector of some non-physical operations. In the next part, we provide a new class of multipartite bound entanglement in mixed state level. The class of states are activable bound entangled. There are exactly four orthogonal activable bound entangled states in any even number of qubit system. They have some interesting features like Bell correlation, permutation symmetry, local Pauli connection, non-compatibility, etc. Apart from those properties, the class of bound entangled states have the remarkable feature of local indistinguishability in quantum systems.