Mirror inversion of quantum states in linear registers

Transfer of data in linear quantum registers can be significantly simplified with preengineered but not dynamically controlled interqubit couplings. We show how to implement a mirror inversion of the state of the register in each excitation subspace with respect to the center of the register. Our construction is especially appealing as it requires no dynamical control over individual interqubit interactions. If, however, individual control of the interactions is available then the mirror inversion operation can be performed on any substring of qubits in the register. In this case, a sequence of mirror inversions can generate any permutation of a quantum state of the involved qubits.     

Instability of Interfaces in the Antiferromagnetic XXZ Chain at Zero Temperature

 For the antiferromagnetic, highly anisotropic XZ and XXZ quantum spin chains, we impose periodic boundary conditions on chains with an odd number of sites to force an interface (or kink) into the chain. We prove that the energy of the interface depends on the momentum of the state. This shows that at zero temperature the interface in such chains is not stable. This is in contrast to the ferromagnetic XXZ chain for which the existence of localized interface ground states has been proven for any amount of anisotropy in the Ising-like regime. Received: 15 August 2002 / Accepted: 8 January 2003 Published online: 14 April 2003 RID="⋆" ID="⋆" ? Copyright rests with the authors. Reproduction of the entire article for non-commercial purposes is permitted. Communicated by M. Aizenman     

Entanglement cost in practical scenarios

We quantify the one-shot entanglement cost of an arbitrary bipartite state, that is, the minimum number of singlets needed by two distant parties to create a single copy of the state up to a finite accuracy, by using local operations and classical communication only. This analysis, in contrast to the traditional one, pertains to scenarios of practical relevance, in which resources are finite and transformations can be achieved only approximately. Moreover, it unveils a fundamental relation between two well-known entanglement measures, namely, the Schmidt number and the entanglement of formation. Using this relation, we are able to recover the usual expression of the entanglement cost as a special case.     

Heavier Tetrylenes as Single Site Catalysts

An overview of the development of compounds with heavier low-valent group 14 elements (known as tetrylenes) as single component catalyst for organic transformation has been provided. Compounds with heavier group 14 elements possess stereochemically active lone pairs and energetically accessible π-antibonding orbitals, thereby resembling the electronic configuration of transition-metal compounds. Such compounds with low-valent group 14 elements has been known for small molecule activation since Power's report of dihydrogen activation by a digermyne, but their utilization in catalysis remained as a “Holy Grail” in main group chemistry. In recent years, numerous methodologies have been discovered epitomizing the use of Si(II), Ge(II) and Sn(II) compounds as single site catalysts for hydroboration of aldehydes, ketones, pyridines, cyanosilylation of aldehydes and ketones, N-formylations aromatic amines, dehydrocoupling reactions. This mini-review highlights these significant developments with an emphasis on the mechanistic investigation.     

A multi-charged particle model with local U(1)μ-τ to explain muon g–2, flavor physics,and possible collider signature

We consider a model with multi-charged particles, including vector-like fermions, and a charged scalar under a local \begin{document}$ U(1)_{\mu - \tau} $\end{document} symmetry. We search for an allowed parameter region explaining muon anomalous magnetic moment (muon \begin{document}$ g-2 $\end{document}) and \begin{document}$ b \to s \ell^+ \ell^- $\end{document} anomalies, satisfying constraints from the lepton flavor violations, Z boson decays, meson anti-meson mixing, and collider experiments. Via numerical analysis, we explore the typical size of the muon \begin{document}$ g-2 $\end{document} and Wilson coefficients to explain the \begin{document}$ b \to s \ell^+ \ell^- $\end{document} anomalies in our model when all other experimental constraints are satisfied. Subsequently, we discuss the collider physics of the multicharged vectorlike fermions, considering a number of benchmark points in the allowed parameter space.     

Effect of dispersion on the diffusion zone in two-phase laminar flows in microchannels

Aim of the present work is to investigate the reaction–diffusion process of a two species system under laminar flow in a T-shaped microchannel. A zone formed at the interface between the aqueous solutions of these two species is affected by advection and diffusion. Through theoretical analyses and experimental results, the effect of dispersion has been shown to influence this diffusion zone. We have defined a parameter called effective diffusivity, to account for the dispersion effects and observed it to be a function of the channel Peclet number. In the limiting case of low Peclet number, this parameter is constant and turns out to be equal to the molecular diffusivity. We have also related effective diffusivity and the dispersion coefficient through scaling estimates.     

Hydrogen Peroxide Solvates of 2,4,6,8,10,12‐Hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane

Two polymorphic hydrogen peroxide solvates of 2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane (CL‐20; wurtzitane is an alternative name to iceane) were obtained using hydrated α‐CL‐20 as a guide. These novel H₂O₂ solvates have high crystallographic densities (1.96 and 2.03 g cm^?3, respectively), high predicted detonation velocities/pressures (with one solvate performing better than ?‐CL‐20), and a sensitivity similar to that of ?‐CL‐20. The use of hydrated materials as a guide will be important in the development of other energetic materials with hydrogen peroxide. These solvates represent an area of energetic materials that has yet to be explored.     

Enhancement of static incubation time in microfluidic cell culture platforms exploiting extended air-liquid interface

Microfluidics based cell culture applications have facilitated the study of cellular dynamics at the single entity level. Yet, long term versions of such applications in a static framework suffer from the fast exhaustion of available oxygen, dissolved in the limited media volume available per cell, within the microconfined environment. In order to circumvent such drawbacks, we have improvised a microfluidic cell culture platform for prolonged sustenance of adherent mammalian cells by formation of an air-liquid interface through functionalizing inner surfaces of a polydimethylsiloxane (PDMS) based microdevice. We have demonstrated an augmented static incubation time for different cell lines using this approach.