A streamlined method for chiral fermions on the lattice

We discuss the use of renormalization counterterms to restore the chiral gauge symmetry in a lattice theory of Wilson fermions. We show that a large class of counterterms can be implemented automatically by making a simple modification to the fermion determinant.Comment: 4 pages, ANL-HEP-CP-92-10

Quadratic operators used in deducing exact ground states for correlated systems: ferromagnetism at half filling provided by a dispersive band

Quadratic operators are used in transforming the model Hamiltonian (H) of one correlated and dispersive band in an unique positive semidefinite form coopting both the kinetic and interacting part of H. The expression is used in deducing exact ground states which are minimum energy eigenstates only of the full Hamiltonian. It is shown in this frame that at half filling, also dispersive bands can provide ferromagnetism in exact terms by correlation effects .Comment: 7 page

Mechanical and GWP Assessment of Concrete Using Blast Furnace Slag, Silica Fume and Recycled Aggregate

Demolition waste and cement production is responsible for 36% of total waste produced on earth and 8% of the worlds CO2 emissions, respectively. Due to limited research on concrete mixes containing ternary cementitious mixes (Ground Granulated Blast-furnace Slag (GGBS) and Silica Fume (SF)) and demolition waste, the paper reviewed the mechanical properties of concrete, and structural performance of reinforced beams. Thereafter, life cycle analysis (LCA) was investigated to understand the true environmental impact, focusing on Global Warming Potential (GWP). Results show that recycled concrete aggregates (RCA) had no significant negative impact on the compressive strength, tensile strength, and modulus of rupture of concrete. The inclusion of GGBS and SF in mixes containing RCA eliminated any negative impact and for all mixes produced greater strengths in comparison to the control mix, due to the secondary reaction of Ca (OH)2 and pore refinement. The flexural behavior of the concrete beams with 0%, 25%, 50% and 100% RCA, 25% GGBS and 5% SF is similar. LCA results showed that replacing NA with 25%, 50% or 100% RCA has no significant impact on the GWP emissions. This is because of the similar emissions associated with manufacturing and processing of recycled and natural aggregates. However, replacing cement with 5% SF and 25% GGBS improves the GWP environmental response of concrete significantly. Additionally, natural aggregates have a higher GWP contribution than that of recycled concrete aggregates by almost 80% since the process of NA required quarry operation and transportation while the RCA are produced on site from an existing building waste

Spin-lattice coupling in the ferrimagnetic semiconductor FeCr2S4 probed by surface acoustic waves

Using surface acoustic waves, the elastomagnetic coupling could be studied in thin single crystalline plates of the ferrimagnetic semiconductor FeCr2S4 by measuring the attenuation and the frequency tracking in the temperature range 4.2 K to 200 K. The data clearly display the anomalies found in low-field magnetization measurements.Comment: 15 pages, 3 figures. To appear in J. Appl. Phys., 99 (2006

Microstructures in Two Alkali Feldspar Megacrysts from the Papuk Mt., Croatia

Two types of megacrysts, one from Pakra Creek and the other from the Slobostina Creek locality proved to be low microcline in association with low albite and quartz. A sample from Pakra Creek is a vein filling megacryst characterised by the absence of twinning. The deduced crystallization temperature is below 460°C. The sample from Sloboština Creek is a pocket forming megacryst which shows tweed-like texture, with deduced crystallization temperature near to but above 460°C. Both samples are characterized by a continuously modulated lattice on the submicroscopic scale

Nonlinear semigroups for nonlocal conservation laws

We investigate a class of nonlocal conservation laws in several space dimensions, where the continuum average of weighted nonlocal interactions are considered over a finite horizon. We establish well-posedness for a broad class of flux functions and initial data via semigroup theory in Banach spaces and, in particular, via the celebrated Crandall–Liggett Theorem. We also show that the unique mild solution satisfies a Kružkov-type nonlocal entropy inequality. Similarly to the local case, we demonstrate an efficient way of proving various desirable qualitative properties of the unique solution

Vacuum instability in the Abelian Higgs model with strings

Using the effective potential approach for composite operators, we have analytically evaluated the truly nonperturbative vacuum energy density in the Abelian Higgs model of dual QCD ground state. This quantity is defined as integrating out of the truly nonperturbative part of the full gluon propagator over the deep infrared region (soft momentum region). Defined in this way it is manifestly gauge invariant.We have explicitly shown that the corresponding effective potential always has an imaginary part. This means that the vacuum of this model with string contributions is unstable against quantum corrections.Comment: 7 pages, no tables, no figures. Some clarifications are introduced as well as two more references have been added. To appear in Phys. Lett.