We study entanglement properties of mixed density matrices obtained from combinatorial Laplacians. This is done by introducing the notion of the density matrix of a graph. We characterize the graphsâ€¦ (More)

We reconsider density matrices of graphs as defined in quant-ph/0406165. The density matrix of a graph is the combinatorial Laplacian of the graph normalized to have unit trace. We describe a simpleâ€¦ (More)

The problem of local distinguishability of orthogonal quantum states has raised much interest in the arena of quantum information. Interestingly where any two pure orthogonal states can beâ€¦ (More)

Quantum Teleportation, the transfer of the state of one quantum system to another without direct interaction between both systems, is an important way to transmit information encoded in quantumâ€¦ (More)

We discuss here the best disentanglement processes of states of two twoâ€“level systems which belong to (i) the universal set, (ii) the set in which the states of one party lie on a single great circleâ€¦ (More)

We show that the Bloch vectors lying on any great circle is the largest set SL for which the parallel states |âˆ’ â†’n ,âˆ’ â†’n ã€‰ can always be exactly transformed into the anti-parallel states |âˆ’ â†’n ,âˆ’âˆ’ â†’nâ€¦ (More)

We show that non-Markovian effects of the reservoirs can be used as a resource to extract work from an Otto cycle. The state transformation under non-Markovian dynamics is achieved via a two-stepâ€¦ (More)

Gisin and Popescu (Gisin N and Popescu S 1999 Phys. Rev. Lett. 83 432) have shown that more information about their direction can be obtained from a pair of anti-parallel spins compared to a pair ofâ€¦ (More)

A very interesting feature of semiconductor quantum dots(QDs) is the redshift of emission peaks with respect to absorption spectra and its size dependence. The red shift of the emission spectra withâ€¦ (More)