Dis)Harmony in Illyria: Music, Order, and Time in Twelfth Night:Music, Order, and Time in Twelfth Night

This paper considers the integral aspect of music as performed in Shakespeare's Twelfth Night. It posits that music is that which orders and structures time in its interplay throughout the play.

Entanglement Spectrum, Critical Exponents and Order Parameters in Quantum Spin Chains

We investigate the entanglement spectrum near criticality in finite quantum spin chains. Using finite size scaling we show that when approaching a quantum phase transition, the Schmidt gap, i.e., the difference between the two largest eigenvalues of the reduced density matrix ?1, ?2, signals the critical point and scales with universal critical exponents related to the relevant operators of the corresponding perturbed conformal field theory describing the critical point. Such scaling behavior allows us to identify explicitly the Schmidt gap as a local order parameter.

Magnetic short-range order in the new ternary phase Mn8Pd15Si7

A new compound, Mn8Pd15Si7, is reported to crystallize in a face centered cubic unit cell of dimension a = 12.0141(2) angstrom, space groupFm (3) over barm, and can thus be classified as a G-phase. The crystal structure was studied by single crystal X-ray diffraction, X-ray and neutron powder diffraction and electron diffraction. A filled Mg6Cu16Si7 type structure was found, corresponding to the Sc11Ir4 type structure. The magnetic properties were investigated by magnetization measurements and Reverse Monte Carlo modeling of low temperature magnetic short-range order (SRO). Dominating near neighbor antiferromagnetic correlations were found between the Mn atoms and geometric frustration in combination with random magnetic interactions via metal sites with partial Mn occupancy were suggested to hinder formation of long-range magnetic order. 

Cycloidal magnetic order in the compound IrMnSi

A new compound, IrMnSi, has been synthesized, and its crystal structure and magnetic properties have been investigated by means of neutron powder diffraction, magnetization measurements, and first-principles theory. The crystal structure is found to be of the TiNiSi type (ordered Co2P, space group Pnma). The Mn-projected electronic states are situated at the Fermi level, giving rise to metallic binding, whereas a certain degree of covalent character is observed for the chemical bond between the It and Si atoms. A cycloidal, i.e., noncollinear, magnetic structure was observed below 460 K, with the propagation vector q=[0,0,0.4530(5)] at 10 K. The magnetism is dominated by large moments on the Mn sites, 3.8 mu(B)/atom from neutron diffraction. First-principles theory reproduces the propagation vector of the experimental magnetic structure as well as the angles between the Mn moments. The calculations further result in a magnetic moment of 3.21 mu(B) for the Mn atoms, whereas the Ir and Si moments are negligible, in agreement with observations. A calculation that more directly incorporates electron-electron interactions improves the agreement between the theoretical and experimental magnetic moments. A band mechanism is suggested to explain the observed magnetic order.

First-Order Reversal Curve Probing of Spatially Resolved Polarization Switching Dynamics in Ferroelectric Nanocapacitors

Spatially resolved polarization switching In ferroelectric nanocapacitors was studied on the sub-25 nm scale using the first-order reversal curve (FORC) method. The chosen capacitor geometry allows both high-veracity observation of the domain structure and mapping of polarization switching in a uniform field, synergistically combining microstructural observations and probing of uniform-field polarization responses as relevant to device operation. A classical Kolmogorov-Avrami-Ishibashi model has been adapted to the voltage domain, and the individual switching dynamics of the FORC response curves are well approximated by the adapted model. The comparison with microstructures suggests a strong spatial variability of the switching dynamics inside the nanocapacitors.

Interplay of Octahedral Tilts and Polar Order in BiFeO3 Films

Heterointerface stabilization of a distinct nonpolar BiFeO3 phase occurs simultaneously with changes in octahedral tilts. The resulting phase arises via suppression of polarization by a structural order parameter and can thus be identified as anti-ferroelectric (Fe displacements - bottom panel). The phase is metastable and can be switched into a polar ferroelectric state (top panel) under an applied electric bias.

Surface energy and surface proton order of the ice Ih basal and prism surfaces

Density-functional theory (DFT) is used to examine the basal and prism surfaces of ice Ih. Similar surface energies are obtained for the two surfaces; however, in each case a strong dependence of the surface energy on surface proton order is identified. This dependence, which can be as much as 50% of the absolute surface energy, is significantly larger than the bulk dependence (< 1%) on proton order, suggesting that the thermodynamic ground state of the ice surface will remain proton ordered well above the bulk order-disorder temperature of about 72 K. On the basal surface this suggestion is supported by Monte Carlo simulations with an empirical potential and solution of a 2D Ising model with nearest neighbor interactions taken from DFT. Order parameters that define the surface energy of each surface in terms of nearest neighbor interactions between dangling OH bonds (those which point out of the surface into vacuum) have been identified and are discussed. Overall, these results suggest that proton order-disorder effects have a profound impact on the stability of ice surfaces and will most likely have an effect on ice surface reactivity as well as ice crystal growth and morphology. S Supplementary data are available from stacks.iop.org/JPhysCM/22/074209/mmedia

On thin ice: surface order and disorder during pre-melting

The effect of temperature on the structure of the ice Ih (0001) surface is considered through a series of molecular dynamics simulations on an ice slab. At relatively low temperatures (200K) a small fraction of surface self-interstitials (i.e. admolecules) appear that are formed exclusively from molecules leaving the outermost bilayer. At higher temperatures (ca. 250 K), vacancies start to appear in the inner part of the outermost bilayer exposing the underlying bilayer and providing sites with a high concentration of the dangling hydrogen bonds. Around 250-260 K aggregates of molecules formed on top of the outermost bilayer from self-interstitials become more mobile and have diffusivities approaching that of liquid water. At similar to 270-280 K the inner bilayer of one surface noticeably destructures and it appears that at above 285 K both surfaces are melting. The observed disparity in the onset of melting between the two sides of the slab is rationalised by considering the relationship between surface energy and the spatial distribution of protons at the surface; thermodynamic stability is conferred on the surface by maximising separations between dangling protons at the crystal exterior. Local hotspots associated with a high dangling proton density are suggested to be susceptible to pre-melting and may be more efficient at trapping species at the external surface than regions with low concentrations of protons thus potentially helping ice particles to catalyse reactions. A preliminary conclusion of this work is that only about 10-20 K below the melting temperature of the particular water potential employed is major disruption of the crystalline lattice noted which could be interpreted as being "liquid", the thickness of this film being about a nanometre.

Surface Energy and Surface Proton Order of Ice Ih

Ice Ih is comprised of orientationally disordered water molecules giving rise to positional disorder of the hydrogen atoms in the hydrogen bonded network of the lattice. Here we arrive at a first principles determination of the surface energy of ice Ih and suggest that the surface of ice is significantly more proton ordered than the bulk. We predict that the proton order-disorder transition, which occurs in the bulk at similar to 72 K, will not occur at the surface at any temperature below surface melting. An order parameter which defines the surface energy of ice Ih surfaces is also identified.

Beaming of High-Order Harmonics Generated from Laser-Plasma Interactions

Beam divergences of high-order extreme ultraviolet harmonics from intense laser interactions with steep plasma density gradients are studied through experiment and Fourier analysis of the harmonic spatial phase. We show that while emission due to the relativistically oscillating mirror mechanism can be explained by ponderomotive surface denting, in agreement with previous results, the divergence of the emission due to the coherent wake emission mechanism requires a combination of the dent phase and an intrinsic emission phase. The temporal dependence of the divergences for both mechanisms is highlighted while it is also shown that the coherent wake emission divergence can be small in circumstances where the phase terms compensate each other. © 2013 American Physical Society.

The Irish High Court Issues its First Order on a Commitment Agreement between the NCA and an Undertaking (Fitflop)

The Irish Competition (Amendment) Act 2012 introduced court-endorsed commitment agreements to Irish competition law. The new section 14B of the principal Competition Act 2002 provides for making commitment agreements between the Irish Competition and undertakings an order of the Irish High Court. This piece, first, investigates the prior Irish practice regarding commitment or settlement agreements and its legal basis. It looks then into the newly introduced rules on court-endorsed commitment agreements. Finally, before concluding, it points to the first instance of their application — to an order issued by the High Court in the FitFlop case in December 2012, which came into effect in February 2013.

Between Order and Modernity: Resurgence Planning in Revolutionary Egypt

Egypt’s Revolution of 1952 presented a major historical change to its political and economic structure, its society, and its institutions. This paper examines how Nasser’s regime operated through the state apparatus to exhibit features of modernity. Under the pretext of modernization, renovating Cairo’s authentic urban fabric was one of the channels that displayed the new ambitions to unveil a centralized system of governance and ideologies of socialism. The paper particularly looks at the city’s resurgence attempts, promoted by upgrading practices that displayed Western ideals of planning. Eventually, the contradictory planning legislative system introduced by the government raised early alarms at the problems encountered in the planning institution that was not only unable to liberate Cairo’s urban districts from its long-rooted decay, but also struggled to implement the regime’s flagship policy of social justice in a context wherein it was much needed.