Perfect state transfer in quantum spin networks

We propose a class of qubit networks that admit the perfect state transfer of any quantum state in a fixed period of time. Unlike many other schemes for quantum computation and communication, these networks do not require qubit couplings to be switched on and off. When restricted to N-qubit spin networks of identical qubit couplings, we show that 2log3N is the maximal perfect communication distance for hypercube geometries. Moreover, if one allows fixed but different couplings between the qubits, then perfect state transfer can be achieved over arbitrarily long distances in a linear chain.     

The impact of carbon surface chemical composition on the adsorption of phenol determined at the real oxic and anoxic conditions

The results of phenol adsorption-desorption isotherms (at 310 K) measured on the series of activated carbons (D43/1, NORIT RO 0.8, D55/2) are presented. The effect of carbon surface chemical composition on phenol adsorption determined at real oxic and anoxic conditions is discussed. To obtain the real anoxic conditions the two station controlled atmosphere chamber with two catalyst heater units (Plas Labs, Lansing, MI, USA) was applied. It is shown that the adsorption under oxic conditions is always larger than that determined for anoxic ones for all studied carbons. The analysis of those differences shows that in the range of micropore filling they decrease with the equilibrium phenol mole fraction in solution. Contrary they increase after micropores being filled. The average differences between the adsorption properties are the linear function of the concentration of surface acidic groups (assigned from the Boehm's method as “carboxylic”) calculated per the apparent BET surface area of studied carbons.     

Synthesis of new beta-substituted meso-tetraphenylporphyrins via 1,3-dipolar cycloaddition reactions. 1

The azomethine ylide generated from the reaction of (beta-formyl-meso-tetraphenylporphyrinato)nickel(II) with N-methylglycine reacts with a range of dipolarophiles, yielding new beta-substituted-meso-tetraphenylporphyrins. The regio- and stereochemistry of the new compounds was established using one- and two-dimensional NMR techniques.     

Direct estimations of linear and nonlinear functionals of a quantum state

We present a simple quantum network, based on the controlled-SWAP gate, that can extract certain properties of quantum states without recourse to quantum tomography. It can be used as a basic building block for direct quantum estimations of both linear and nonlinear functionals of any density operator. The network has many potential applications ranging from purity tests and eigenvalue estimations to direct characterization of some properties of quantum channels. Experimental realizations of the proposed network are within the reach of quantum technology that is currently being developed.     

Regular or stochastic dynamics in real analytic families of unimodal maps

In this paper we prove that in any non-trivial real analytic family of quasiquadratic maps, almost any map is either regular (i.e., it has an attracting cycle) or stochastic (i.e., it has an absolutely continuous invariant measure). To this end we show that the space of analytic maps is foliated by codimension-one analytic submanifolds, hybrid classes. This allows us to transfer the regular or stochastic property of the quadratic family to any non-trivial real analytic family. To Jacob Palis on his 60th birthdayMathematics Subject Classification (2000) 37E05, 37F45, 30D05     

Tomographic quantum cryptography: equivalence of quantum and classical key distillation

The security of a cryptographic key that is generated by communication through a noisy quantum channel relies on the ability to distill a shorter secure key sequence from a longer insecure one. For an important class of protocols, which exploit tomographically complete measurements on entangled pairs of any dimension, we show that the noise threshold for classical advantage distillation is identical with the threshold for quantum entanglement distillation. As a consequence, the two distillation procedures are equivalent: neither offers a security advantage over the other.     

Isolation and structural elucidation of 5-formyl-2,3-dihydroisocoumarin from Centaurium erythraea aerial parts

An isocoumarin was isolated from the aerial parts of Centauriwn erythraea Rafn. (Gentianaceae). Its structure was established by spectroscopic means as 5-formyl-2,3-dihydroisocoumarin.     

Annealing behavior of the Kondo-type zero-bias conductance peak in Ta-Ta2O5-Ag tunneling junctions

In annealing Ta-Ta₂O₅-Ag tunneling junctions the oxide barrier of which has been prepared by short-time room temperature oxidation, we observe a systematic decrease of the well-known Kondo-Appelbaum zero-bias anomaly. This decrease is due to electron transfer from low oxidation state magnetic Ta ions in the barrier near the Ta electrode to oxygen near the Ag electrode.     

Moderne Entwicklung der NMR (Nuclear Magnetic Resonance)

Modern Development of NMR (Nuclear Magnetic Resonance) The age of NMR-spectroscopy is not comparable with that of the Annalen der Physik; NMR was established only about 45 years ago. Its development was promoted by different experience, knowledge and techniques; it shows that also in these days the progress of a special topic depends on stimulations by other parts of physics, of natural and technical science. In an analogous way general scientific journals are not made superfluous by the existence of special papers. These relations are demonstrated with some examples in NMR.