Splitting Ward identity

Within the background-field framework we present a path integral derivation of the splitting Ward identity for the one-particle irreducible effective action in the presence of an infrared regulator, and make connection with earlier works on the subject. The approach is general in the sense that it does not rely on how the splitting is performed. This identity is then used to address the problem of background dependence of the effective action at an arbitrary energy scale. We next introduce the modified master equation and emphasize its role in constraining the effective action. Finally, application to general gauge theories within the geometric approach is discussed.Comment: 26 pages; v2: "Conclusions" section added, two paragraphs added to further clarify the gauge-fixing procedure, typos fixed, minor other improvements, to appear in EPJ

Effect of two-step pretreatment on cobalt contents and surface roughness of tungsten carbide substrate prior to diamond coating

Cemented tungsten carbide is the most widely used material for cutting tools. Due to extreme demands higher tool life several types of coating have been introduced to prolong the service time which include diamond coating. However cobalt binder in tungsten carbide prevents diamond to adhere well on the substrate and its content at the outer surface should be reduce to below 1%. Single step and two-step pretreatments have been studied by many researchers. But to date poor adhesion of diamond coating still an issue. In this work a two-step pretreatment was used to etch tungsten carbide with 6% cobalt (WC-6% Co) at the surface of the substrate in order to solve poor adhesion problem. First step with Murakami's reagent (2, 3, 6, and 20 minutes) and the second step of the process were carried out by etching in a solution of hydrochloric acid (30, 45, and 60 seconds) or a solution of sulfuric acid (10 seconds). The effect of them on Co cemented tungsten carbide samples in term of surface morphology, surface roughness, and cobalt removal from the surface were examined. It is found the longer Murakami etching time produces a slightly rougher surface than the shorter exposing time. Both acid solutions were used in the second pretreatment step able to reduce cobalt content to below 1% at all conditions regardless of etching time. The best combination of pretreatment process is 20 minutes Murakami etching and 45 seconds exposure time of hydrochloric acid that yields the higher surface roughness and the lowest cobalt content on the substrate surface

Dividend Yield and Stock Return in Different Economic Environment: Evidence from Malaysia

This study investigates the relationship between dividend yields and stock returns in bull and bear markets. Evidences from developed countries show that there should be a positive correlation between dividend yields and stock return in bear markets and a negative correlation between dividend yields and stock return during the bull markets. Findings of this study, in emerging market content, show that there is a positive relation between dividend yield and stock returns in both bull and bear markets which are not consistent with previous works.Dividend Yield; Stock Return; Economic Environment; Bull/Bear Market; Malaysia

Quantum mechanical evolution operator in the presence of a scalar linear potential: discussion on the evolved state

We discuss the form of the wave-function of a state subjected to a scalar linear potential, paying special attention to quantum tunneling. We analyze the phases acquired by the evolved state and show that some of them have a pure quantum mechanical origin. In order to measure one of these phases, we propose a simple experimental scenario. We finally apply the evolution equations to re-analyze the Stern\&Gerlach experiment and to show how to manipulate spin by employing constant electric fields.Comment: in press in Physica Script