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Quantum computer

Sivaraman Somasundaram, Eswaran Kamaraj, Su Jin Hwang, Sanghyuk Park
Imidazole-based excited state intramolecular proton transfer (ESIPT) blue fluorescent molecules, 2-(1-(4-chlorophenyl)-4,5-diphenyl-1H-imidazol-2-yl)phenol (BHPI-Cl) and 2-(1-(4-bromophenyl)-4,5-diphenyl-1H-imidazol-2-yl)phenol (BHPI-Br) were designed and synthesized by Debus-Radziszewski method through a one-pot multicomponent reaction in high yield. The synthesized compounds were fully characterized by (1)H NMR, (13)C NMR, FT-IR, FT-Raman, GC-Mass, and elemental analysis. The molecular structures in single crystal lattice were studied by X-ray crystallographic analysis...
October 14, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Andrey Gromov, Scott D Geraedts, Barry Bradlyn
We construct a low energy effective theory of anisotropic fractional quantum Hall (FQH) states. We develop a formalism similar to that used in the bimetric approach to massive gravity, and apply it to describe Abelian anisotropic FQH states in the presence of external electromagnetic and geometric backgrounds. We derive a relationship between the shift, the Hall viscosity, and a new quantized coupling to anisotropy, which we term anisospin. We verify this relationship by numerically computing the Hall viscosity for a variety of anisotropic quantum Hall states using the density matrix renormalization group...
October 6, 2017: Physical Review Letters
Mario Motta, Shiwei Zhang
We address the computation of ground-state properties of chemical systems and realistic materials within the auxiliary-field quantum Monte Carlo method. The phase constraint to control the fermion phase problem requires the random walks in Slater determinant space to be open-ended with branching. This in turn makes it necessary to use back-propagation (BP) to compute averages and correlation functions of operators that do not commute with the Hamiltonian. Several BP schemes are investigated and their optimization with respect to the phaseless constraint is considered...
October 20, 2017: Journal of Chemical Theory and Computation
Dmitry M Kuznetsov, Andrei G Kutateladze
Atom- and step-economy in photoassisted DOS is achieved with a versatile oxalyl linker offering rapid access to complex alkaloid mimics in very few experimentally simple steps: (i) it allows for fast tethering of the photoactive core to the unsaturated pendants, especially im-portant in the case of (hetero)aromatic amines - essentially a one pot reaction with no isolation of intermediates; (ii) the α-dicarbonyl tether acts as a chromophore enhancer, extending the conjugation chain and facilitating the 'harvest' of the lower energy photons for the primary and secondary photoreactions, (iii) it enhances the quantum yield of intersystem crossing (ISC), i...
October 20, 2017: Journal of the American Chemical Society
Steven Schramm
No abstract text is available yet for this article.
October 18, 2017: Nature
Xiao-Shan Ye, Yong-Jun Liu, Xiu Yun Zhang, Guoqing Wu
We explore the topological phase, which involves Majorana type topological zero mode fermions (MTZFs) at the edge, using d-wave superfluid with Rashba spin-orbit coupling (SOC) interactions. The self-Hermitian of this MTZF([Formula: see text]) is similar to that of the Majorana fermions (MFs) ([Formula: see text]). We show that, to realize a single MTZF at each edge in superfluid with d-wave pairing in a Majorana type Kramers Doublet (MTKD) state, it is important to lift both the spin and the Dirac Cones degeneracies...
October 19, 2017: Scientific Reports
S A Owerre, J Nsofini
Quantum information storage using charge-neutral quasiparticles is expected to play a crucial role in the future of quantum computers. In this regard, magnons or collective spin-wave excitations in solid-state materials are promising candidates in the future of quantum computing. Here, we study the quantum squeezing of Dirac and topological magnons in a bosonic honeycomb optical lattice with spin-orbit interaction by utilizing the mapping to quantum spin-[Formula: see text] XYZ Heisenberg model on the honeycomb lattice with discrete Z2 symmetry and a Dzyaloshinskii-Moriya interaction...
October 19, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Sarah Friedensen, Jerome T Mlack, Marija Drndić
Focused ion beam milling allows manipulation of the shape and size of nanostructures to create geometries potentially useful for opto-electronics, thermoelectrics, and quantum computing. We focus on using the ion beam to control the thickness of Bi2Se3 and to create nanowires from larger structures. Changes in the material structure of Bi2Se3 nanomaterials that have been milled using a focused ion beam are presented. In order to characterize the effects of ion beam processing on the samples, we use a variety of techniques including analytical transmission electron microscopy and atomic force microscopy...
October 18, 2017: Scientific Reports
Kuduva R Vignesh, Alessandro Soncini, Stuart K Langley, Wolfgang Wernsdorfer, Keith S Murray, Gopalan Rajaraman
Toroidal quantum states are most promising for building quantum computing and information storage devices, as they are insensitive to homogeneous magnetic fields, but interact with charge and spin currents, allowing this moment to be manipulated purely by electrical means. Coupling molecular toroids into larger toroidal moments via ferrotoroidic interactions can be pivotal not only to enhance ground state toroidicity, but also to develop materials displaying ferrotoroidic ordered phases, which sustain linear magneto-electric coupling and multiferroic behavior...
October 18, 2017: Nature Communications
Thien Nguyen, Charles D Hill, Lloyd C L Hollenberg, Matthew R James
Solid-state spin-based qubits offer good prospects for scaling based on their long coherence times and nexus to large-scale electronic scale-up technologies. However, high-threshold quantum error correction requires a two-dimensional qubit array operating in parallel, posing significant challenges in fabrication and control. While architectures incorporating distributed quantum control meet this challenge head-on, most designs rely on individual control and readout of all qubits with high gate densities. We analysed the fan-out routing overhead of a dedicated control line architecture, basing the analysis on a generalised solid-state spin qubit platform parameterised to encompass Coulomb confined (e...
October 17, 2017: Scientific Reports
Feng Li, Lai You, Chao Nie, Qin Zhang, Xiao Jin, Haiyang Li, Xiaobing Gu, Yan Huang, Qinghua Li
Alloy core/shell CdxZn1-xS/ZnS quantum dots (QDs) are emerging as robust candidates for light-emitting diodes (LEDs), however the emission range of the current CdxZn1-xS/ZnS is quite limited, ranging from 390 to 470 nm. It still remains a challenging task to construct white LEDs based on current CdxZn1-xS/ZnS system. Here, a versatile ZnSe with a moderate band gap is introduced onto the Cd0.1Zn0.9S core. The ZnSe shell, on one hand, can passivate the core surface which leads to bright emissions. On the other hand, it is essential in extending the emission to red region so that the emission wavelengths of Cd0...
September 4, 2017: Optics Express
Mladen Pavičić, Oliver Benson, Andreas W Schell, Janik Wolters
Two-qubit quantum codes have been suggested to obtain better efficiency and higher loss tolerance in quantum key distribution. Here, we propose a two-qubit quantum key distribution protocol based on a mixed basis consisting of two Bell states and two states from the computational basis. All states can be generated from a single entangled photon pair resource by using local operations on only one auxiliary photon. Compared to other schemes it is also possible to deterministically discriminate all states using linear optics...
October 2, 2017: Optics Express
Piotr Roztocki, Michael Kues, Christian Reimer, Benjamin Wetzel, Stefania Sciara, Yanbing Zhang, Alfonso Cino, Brent E Little, Sai T Chu, David J Moss, Roberto Morandotti
The on-chip generation of large and complex optical quantum states will enable low-cost and accessible advances for quantum technologies, such as secure communications and quantum computation. Integrated frequency combs are on-chip light sources with a broad spectrum of evenly-spaced frequency modes, commonly generated by four-wave mixing in optically-excited nonlinear micro-cavities, whose recent use for quantum state generation has provided a solution for scalable and multi-mode quantum light sources. Pulsed quantum frequency combs are of particular interest, since they allow the generation of single-frequency-mode photons, required for scaling state complexity towards, e...
August 7, 2017: Optics Express
A Kessentini, A Ben Ahmed, T Dammak, M Belhouchet
The current work undertakes the growth and the physicochemical properties of a novel green-yellow luminescence semi-organic material, the 3-picolylammonium bromide abbreviated (Pico-Br). In this paper, we report the X-ray diffraction measurements which show that the crystal lattice consists of distinct 3-picolylammonium cations and free bromide anions connected via NH⋯Br and NH⋯N hydrogen bonds leading to form a two dimensional frameworks. Molecular geometry compared with its optimized counterpart shows that the quantum chemical calculations carried out with density functional method (DFT) well produce the perceived structure by X-ray resolution of the studied material...
October 13, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Haiyang Zhang, Yang Jiang, Hai Yan, Ziheng Cui, Chunhua Yin
Experimental observations for ionic hydration free energies are highly debated mainly due to the ambiguous absolute hydration free energy of proton, 〖∆G〗_hyd^* (H^+). Hydration free energies (HFEs) of the 112 singly-charged ions in the Minnesota solvation database were predicted by six methods with explicit and implicit solvent models, namely, Thermodynamic Integration (TI), Energy Representation module (ERmod), Three-Dimensional Reference Interaction Site Model (3D-RISM), and continuum Solvation Models based on the quantum mechanical charge Density (SMD) and on the Poisson-Boltzmann (PB) and Generalized Born (GB) theories...
October 17, 2017: Journal of Chemical Information and Modeling
Tomáš Slanina, Pradeep Shrestha, Eduardo Palao, Dnyaneshwar Kand, Julie A Peterson, Andrew S Dutton, Naama Rubinstein, Roy Weinstain, Arthur H Winter, Petr Klán
A detailed investigation of the photophysical parameters and photochemical reactivity of meso-methyl BODIPY photoremovable protecting groups was accomplished through systematic variation of the leaving group (LG) and core substituents as well as substitutions at boron. Efficiencies of the LG release were evaluated using both steady-state and transient absorption spectroscopies as well as computational analyses to identify the optimal structural features. We find that the quantum yields for photorelease with this photocage are highly sensitive to substituent effects...
October 17, 2017: Journal of the American Chemical Society
Otoniel Denis-Alpizar, Oliver T Unke, Raymond J Bemish, Markus Meuwly
The collision of N2(+) with Ar is studied using quantum and classical methods. The dynamics was followed on a new potential energy surface based on ab initio energies computed at the UCCSD(T)-F12a/aug-cc-pVTZ level, using the correct analytical long range behaviour and a reproducing kernel representation. Comparison with multi-reference MRCI+Q calculations establish that UCCSD(T)-F12a is a sufficiently high level of theory for this problem. Results from quantum close coupling and quasiclassical trajectory calculations agree favourably with each other and the rates for inelastic collisions are lower than those from Langevin theory...
October 17, 2017: Physical Chemistry Chemical Physics: PCCP
Steven Dajnowicz, Ryne C Johnston, Jerry M Parks, Matthew P Blakeley, David A Keen, Kevin L Weiss, Oksana Gerlits, Andrey Kovalevsky, Timothy C Mueser
Enzymes dependent on pyridoxal 5'-phosphate (PLP, the active form of vitamin B6) perform a myriad of diverse chemical transformations. They promote various reactions by modulating the electronic states of PLP through weak interactions in the active site. Neutron crystallography has the unique ability of visualizing the nuclear positions of hydrogen atoms in macromolecules. Here we present a room-temperature neutron structure of a homodimeric PLP-dependent enzyme, aspartate aminotransferase, which was reacted in situ with α-methylaspartate...
October 16, 2017: Nature Communications
Andrey A Fokin, Tatyana S Zhuk, Sebastian Blomeyer, Cristóbal Pérez, Lesya V Chernish, Alexander Pashenko, Jens Antony, Yury V Vishnevskiy, Raphael Jf Berger, Stefan Grimme, Christian Logemann, Melanie Schnell, Norbert W Mitzel, Peter R Schreiner
The covalent diamantyl (C28H38) and oxadiamantyl (C26H34O2) dimers are stabilized by London dispersion attractions between the dimer moieties. Their solid state and gas phase structures were studied using a multi-technique approach including single-crystal X-ray diffraction (XRD), gas-phase electron diffraction (GED), a combined GED/microwave (MW) spectroscopy study, and quantum-chemical calculations. The inclusion of medium-range electron correlation as well as the London dispersion energy in density functional theory is essential to reproduce the experimental geometries...
October 17, 2017: Journal of the American Chemical Society
Xin Li, Tao Liao, Lung Wa Chung
The photoinduced Zimmerman di-π-methane (DPM) rearrangement of polycyclic molecules to form synthetically useful cyclopropane derivatives was found experimentally to proceed in a triplet excited state. We have applied state-of-the-art quantum mechanical methods, including M06-2X, DLPNO-CCSD(T) and variational transition-state theory with multidimensional tunneling corrections, to an investigation of the reaction rates of the two steps in the triplet DPM rearrangement of dibenzobarrelene, benzobarrelene and barrelene...
October 16, 2017: Journal of the American Chemical Society
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