Unmodulated spin chains as universal quantum wires

We study a quantum state transfer between two qubits interacting with the ends of a quantum wire consisting of linearly arranged spins coupled by an excitation conserving, time-independent Hamiltonian. We show that if we control the coupling between the source and the destination qubits and the ends of the wire, the evolution of the system can lead to an almost perfect transfer even in the case in which all nearest-neighbour couplings between the internal spins of the wire are equal.Comment: 4 pages, 5 figure

Trapping a particle of a quantum walk on the line

We observe that changing a phase at a single point in a discrete quantum walk results in a rather surprising localization effect. For certain values of this phase change the possibility of localization strongly depends on the internal coin-state of the walker.Comment: 5 pages, 4 figure

Influence of N-Alkanes on Adhesion of an Air Bubble to the Surface of Low-Rank Coals

Measurements of the detachment force of an air bubble from the surface of coals of the ranks: 31.1, 31.2, 32.1 and 32.2 were carried out. The coal surface was precovered with n-alkane film in the homo logous series from n-hexane to n-hexadecane. The forces were compared with those calculated theoretically on the basis of the previously determined values of the surface free energy components and of the contact angles measured in a coal/n-alkane film - air bubble - water system. On the basis of the conducted measurements and calculations we confirmed that the stability of the coal/n-alkane film - air bubble - water systems depends on the rank of the coal studied, the thickness and kind of the hydrocarbon film present on the coal surface, and on the water film pressure under the air bubble. We also confirmed that the stability of n-alkane films on the surface of the coals studied is smaller than the stability of these films on the surface of typical hydrophobic solids. By comparison of the measured and calculated stabilities of the coal/n-alkane film - air bubble - water system it appeared that the stabilities of such systems may be predicted on the basis of the contact angle of the coal/n-alkane film - air bubble - water system and of the dispersion and nondispersion components of the surface free energy of coal

Influence of N-Alkanes on Adhesion of an Air Bubble to the Surface of Low-Rank Coals

Measurements of the detachment force of an air bubble from the surface of coals of the ranks: 31.1, 31.2, 32.1 and 32.2 were carried out. The coal surface was precovered with n-alkane film in the homo logous series from n-hexane to n-hexadecane. The forces were compared with those calculated theoretically on the basis of the previously determined values of the surface free energy components and of the contact angles measured in a coal/n-alkane film - air bubble - water system. On the basis of the conducted measurements and calculations we confirmed that the stability of the coal/n-alkane film - air bubble - water systems depends on the rank of the coal studied, the thickness and kind of the hydrocarbon film present on the coal surface, and on the water film pressure under the air bubble. We also confirmed that the stability of n-alkane films on the surface of the coals studied is smaller than the stability of these films on the surface of typical hydrophobic solids. By comparison of the measured and calculated stabilities of the coal/n-alkane film - air bubble - water system it appeared that the stabilities of such systems may be predicted on the basis of the contact angle of the coal/n-alkane film - air bubble - water system and of the dispersion and nondispersion components of the surface free energy of coal

Synthesis and electrical characterization of intrinsic and in situ doped Si nanowires using a novel precursor

Perchlorinated polysilanes were synthesized by polymerization of tetrachlorosilane under cold plasma conditions with hydrogen as a reducing agent. Subsequent selective cleavage of the resulting polymer yielded oligochlorosilanes SinCl2n+2 (n = 2, 3) from which the octachlorotrisilane (n = 3, Cl8Si3, OCTS) was used as a novel precursor for the synthesis of single-crystalline Si nanowires (NW) by the well-established vapor–liquid–solid (VLS) mechanism. By adding doping agents, specifically BBr3 and PCl3, we achieved highly p- and n-type doped Si-NWs by means of atmospheric-pressure chemical vapor deposition (APCVD). These as grown NWs were investigated by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM), as well as electrical measurements of the NWs integrated in four-terminal and back-gated MOSFET modules. The intrinsic NWs appeared to be highly crystalline, with a preferred growth direction of [111] and a specific resistivity of ρ = 6 kΩ·cm. The doped NWs appeared to be [112] oriented with a specific resistivity of ρ = 198 mΩ·cm for p-type Si-NWs and ρ = 2.7 mΩ·cm for n-doped Si-NWs, revealing excellent dopant activation

Complementarity in quantum walks

We study discrete-time quantum walks on $d$-cycles with a position and coin-dependent phase-shift. Such a model simulates a dynamics of a quantum particle moving on a ring with an artificial gauge field. In our case the amplitude of the phase-shift is governed by a single discrete parameter $q$. We solve the model analytically and observe that for prime $d$ there exists a strong complementarity property between the eigenvectors of two quantum walk evolution operators that act in the $2d$-dimensional Hilbert space. Namely, if $d$ is prime the corresponding eigenvectors of the evolution operators obey $|\langle v_q|v'_{q'} \rangle| \leq 1/\sqrt{d}$ for $q\neq q'$ and for all $|v_q\rangle$ and $|v'_{q'}\rangle$. We also discuss dynamical consequences of this complementarity. Finally, we show that the complementarity is still present in the continuous version of this model, which corresponds to a one-dimensional Dirac particle.Comment: 5+7 pages, 2 figures, comments welcom

Similarity-based Memory Enhanced Joint Entity and Relation Extraction

Document-level joint entity and relation extraction is a challenging information extraction problem that requires a unified approach where a single neural network performs four sub-tasks: mention detection, coreference resolution, entity classification, and relation extraction. Existing methods often utilize a sequential multi-task learning approach, in which the arbitral decomposition causes the current task to depend only on the previous one, missing the possible existence of the more complex relationships between them. In this paper, we present a multi-task learning framework with bidirectional memory-like dependency between tasks to address those drawbacks and perform the joint problem more accurately. Our empirical studies show that the proposed approach outperforms the existing methods and achieves state-of-the-art results on the BioCreative V CDR corpus

Wettability of Coal Surface and its Surface Free Energy Components

Contact angles were measured for various coal ranks - water drop - n-hexane, n-dodecane and cis-decalin systems. Using the\u27 results obtained the values of the dispersion and nondispersion comnonents of the surface free energy of Polish coal of various ranks, from 31.1 to 35, were calculated. These values (Ysđ and YsP) were compared with those calculated on the basis of measurements of contact anzles conducted earlier for various coal ranks - air bubble or hvdrocarbons dron - water systems. The results obtained allowed us to conclude that, firstlv, the surface free energy of coals results from both the dispersion and nondispersion intermolecular interactions and secondlv, that disnersion components of this energy depend on the coal ranks. The value of nondispersion components of the surf\u27ace free enegzv does not depend on the coal ranks and should not exceed 10 mJ/m2. It was also found that taking into account the values of dispersion components of the studied coals surface free energy we can classify them into three grups: 1) coal rank 31, 2) coal rank32 and 3) coal rank 33, 34 and 35