Two-copy Quantum Teleportation

We investigate two-copy scenario of quantum teleportation based on Bell measurements. The detailed protocol is presented and the general expression of the corresponding optimal teleportation delity is derived, which is given by the two-copy fully entangled fraction that is invariant under local unitary transformations. We prove that under a speci c case of the protocol, which is signi cant for improving the optimal delity, the set of states with their two-copy fully entangled fractions bounded by a threshold value that required for useful two-copy teleportation is convex and compact. Hence the witness operators exist to separate states that are useful for two-copy teleportation from the rest ones. Moreover, we show that the optimal delity of two-copy teleportation surpasses that of the original one copy teleportation.Comment: 8 pages, 2 figure

Ethyl 6-methyl-2-p-tolyl­pyrazolo[1,5-a]pyridine-5-carboxyl­ate

In the title mol­ecule, C18H18N2O2, the bicyclic ring system and the benzene ring form a dihedral angle of 13.45 (3)°. In the crystal structure, weak inter­molecular C—H⋯O hydrogen bonds link mol­ecules into chains propagated along [201]

(5-Bromo-2-methyl­phen­yl)(4-eth­oxy­phen­yl)methanone

In the title compound, C16H15BrO2, the dihedral angle between the benzene rings is 68.5 (2)°. In the crystal structure, mol­ecules are linked by weak C—H⋯O hydrogen bonds into chains parallel to the b axis

Ethyl 6-methyl­sulfanyl-2-phenyl-1H-imidazo[1,2-b]pyrazole-7-carboxyl­ate monohydrate

The title compound, C15H15N3O2S·H2O, has been obtained in a search for new imidazo[1,2-b]pyrazole derivatives with better biological activity. The 1H-imidazo[1,2-b]pyrazole plane forms a dihedral angle of 16.90 (3)° with the benzene ring. π–π inter­actions are indicated by the short distance of 3.643 (2) Å between the centroids of the benzene and imidazole rings. The crystal structure also involves inter­molecular O—H⋯N hydrogen bonds

tert-Butyl N-(5-bromo-1H-imidazo[4,5-b]pyridin-2-ylmeth­yl)carbamate

In the mol­ecule of the title compound, C12H15BrN4O2, the imidazole and pyridine rings are strictly coplanar [maximum deviation 0.006 (3) Å]. In the crystal structure, mol­ecules are linked into chains running parallel to the a axis by inter­molecular N—H⋯O hydrogen bonds. Centrosymmetrically related chains are further connected by N—H⋯N hydrogen-bonding inter­actions to form a two-dimensional layer structure parallel to the ab plane