On self-trapping in the molecular crystal model in onw,two and three dimensions

We present the outcome of a simple variational calculation for the ground-state wavefunction of the molecular crystal model (MCM) on a lattice. We discuss the two-site MCM and the MCM in one, two and three dimensions. For all cases we find a transition to a self-trapped state. The results seem to support our recent Monte Carlo investigations. Our variational results for the two-site MCM, including the presence of the phase transition, are in exact agreement with the rigorous solution for this model.     

Observation of fine structure in the phase locking of a non-linear oscillator

Experimental observations of one-dimensional Poincaré maps of a periodically kicked non-linearly oscillating neon lamp are reported. The complete phase-lock behavior of this oscillator, including superstable phase locking and periodic-doubling bifurcations, could easily be understood with the help of these Poincaré maps.     

Enhancing the violation of the einstein-podolsky-rosen local realism by quantum hyperentanglement

Mermin's observation [Phys. Rev. Lett. 65, 1838 (1990)] that the magnitude of the violation of local realism, defined as the ratio between the quantum prediction and the classical bound, can grow exponentially with the size of the system is demonstrated using two-photon hyperentangled states entangled in polarization and path degrees of freedom, and local measurements of polarization and path simultaneously.     

Bipartite bell inequalities for hyperentangled states

We show that bipartite Bell inequalities based on the Einstein-Podolsky-Rosen criterion for elements of reality and derived from the properties of some hyperentangled states allow feasible experimental verification of the fact that quantum nonlocality grows exponentially with the size of the subsystems, and Bell loophole-free tests with currently available photodetection efficiencies.     

Molecular mechanisms of antibiotic resistance: QM/MM modelling of deacylation in a class A beta-lactamase

Modelling of the first step of the deacylation reaction of benzylpenicillin in the E. coli TEM1 beta-lactamase (with B3LYP/6-31G + (d)//AM1-CHARMM22 quantum mechanics/molecular mechanics methods) shows that a mechanism in which Glu166 acts as the base to deprotonate a conserved water molecule is both energetically and structurally consistent with experimental data; the results may assist the design of new antibiotics and beta-lactamase inhibitors.     

Spin actions in Euclidean and Hermitian Clifford analysis in superspace

In [4] we studied the group invariance of the inner product of supervectors as introduced in the framework of Clifford analysis in superspace. The fundamental group ${\mathrm{SO}}_0$ leaving invariant such an inner product turns out to be an extension of $\text{SO}(m)\times \text{Sp}(2n)$ and gives rise to the definition of the spin group in superspace through the exponential of the so-called extended superbivectors, where the spin group can be seen as a double covering of ${\mathrm{SO}}_0$ by means of the representation $h(s)[x]=sx\stackrel{￣}{s}$. In the present paper, we study the invariance of the Dirac operator in superspace under the classical H and L actions of the spin group on superfunctions. In addition, we consider the Hermitian Clifford setting in superspace, where we study the group invariance of the Hermitian inner product of supervectors introduced in [3]. The group of complex supermatrices leaving this inner product invariant constitutes an extension of $\text{U}(m)\times \text{U}(n)$ and is isomorphic to the subset ${\text{SO}}_0^J$ of ${\text{SO}}_0$ of elements that commute with the complex structure J. The realization of ${\text{SO}}_0^J$ within the spin group is studied together with the invariance under its actions of the super Hermitian Dirac system. It is interesting to note that the spin element leading to the complex structure can be expressed in terms of the n-dimensional Fourier transform.     

Intra‐laser‐cavity microparticle sensing with a dual‐wavelength distributed‐feedback laser

An integrated intra‐laser‐cavity microparticle sensor based on a dual‐wavelength distributed‐feedback channel waveguide laser in ytterbium‐doped amorphous aluminum oxide on a silicon substrate is demonstrated. Real‐time detection and accurate size measurement of single micro‐particles with diameters ranging between 1 µm and 20 µm are achieved, which represent the typical sizes of many fungal and bacterial pathogens as well as a large variety of human cells. A limit of detection of ∼500 nm is deduced. The sensing principle relies on measuring changes in the frequency difference between the two longitudinal laser modes as the evanescent field of the dual‐wavelength laser interacts with micro‐sized particles on the surface of the waveguide. Improvement in sensitivity far down to the nanometer range can be expected upon stabilizing the pump power, minimizing back reflections, and optimizing the grating geometry to increase the evanescent fraction of the guided modes.     

Proposed experiment for testing quantum contextuality with neutrons

We show that an experimental demonstration of quantum contextuality using 2 degrees of freedom of single neutrons based on a violation of an inequality derived from the Peres-Mermin proof of the Kochen-Specker theorem would be more conclusive than those obtained from previous experiments involving pairs of ions [M. A. Rowe, Nature (London) 409, 791 (2001)10.1038/35057215] and single neutrons [Y. Hasegawa, Nature (London) 425, 45 (2003)10.1038/nature01881] based on violations of Clauser-Horne-Shimony-Holt-like inequalities.     

Experimental demonstration of a quantum protocol for byzantine agreement and liar detection

We introduce a new quantum protocol for solving detectable Byzantine agreement (also called detectable broadcast) between three parties, and also for solving the detectable liar detection problem. The protocol is suggested by the properties of a four-qubit entangled state, and the classical part of the protocol is simpler than that of previous proposals. In addition, we present an experimental implementation of the protocol using four-photon entanglement.     

Environmental Sustainability: implications and limitations to Green Chemistry

This study discusses the relationship between Green Chemistry and Environmental Sustainability as expressed in textbooks and articles on Green Chemistry authored by their promoters. It was found that although the Brundtland concept of Sustainable Development/Sustainability has been mentioned often by green chemists, a full analysis of that relationship was almost never attempted. In particular, green chemists have paid scarce attention to the importance of The Second Law of thermodynamics on Environmental Sustainability and the consequences of the limitations it imposes on Green Chemistry, which are discussed in this paper.