Search results for "theories"
showing 10 items of 302 documents
Gaussian effective potential for the standard model SU(2)×U(1) electroweak theory
2008
The Gaussian effective potential is derived for the non-Abelian SU(2)×U(1) gauge theory of electroweak interactions. At variance with naive derivations, the Gaussian effective potential is proven to be a genuine variational tool in any gauge. The role of ghosts is discussed and the unitarity gauge is shown to be the only choice which allows calculability without insertion of further approximations. The full non-Abelian calculation confirms the existence of a light Higgs boson in the nonperturbative strong coupling regime of the Higgs sector.
Introduction
2012
Violation of the equivalence principle from light scalar dark matter
2018
In this paper, we study the local observational consequences of a violation of the Einstein Equivalence Principle induced by models of light scalar Dark Matter (DM). We focus on two different models where the scalar field couples linearly or quadratically to the standard model of matter fields. For both these cases, we derive the solutions of the scalar field. We also derive from first principles the expressions for two types of observables: (i) the local comparison of two atomic sensors that are differently sensitive to the constants of Nature and (ii) the local differential acceleration between two test-masses with different compositions. For the linear coupling, we recover that the signa…
Dynamical environments of relativistic binaries: The phenomenon of resonance shifting
2019
In this article, we explore both numerically and analytically how the dynamical environments of mildly relativistic binaries evolve with increasing the general relativity factor $\gamma$ (the normalized inverse of the binary size measured in the units of the gravitational radius corresponding to the total mass of the system). Analytically, we reveal a phenomenon of the relativistic shifting of mean-motion resonances: on increasing $\gamma$, the resonances between the test particle and the central binary shift, due to the relativistic variation of the mean motions of the primary and secondary binaries and the relativistic advance of the tertiary's pericenter. To exhibit the circumbinary dyna…
Everyday life in old age: past, present, and future
2018
Aims: To explore how older Norwegian women living at home experience ageing, and how their everyday life has been influenced by their encounters with the challenges of life. Methods: A qualitative design, interviewing ten women age 90 or older, was employed. Results: The overall theme of the findings is how everyday life in old age is influenced by past, present and future. The subcategories focus on (a) changes in daily life, (b) giving an account of life as it is, (c) various perceptions of experienced loss, and finally, (d) thoughts about the future. Conclusions: Older women need the opportunity to reflect upon their past, present and future existence to have a good everyday life in old …
Alliance formation as growth opportunity for non-publicly traded companies: a value-added service provided by private equity investors
2016
We analyze the role of Private Equity firms (PE-Firms) as a governance mechanism, focusing on their role as social intermediaries, helping their portfolio companies to form alliances and thereby spurring entrepreneurial growth. Alliances as long term inter-firm cooperations are considered to be a main source of firm-innovation. External growth via alliances is especially important for small to medium sized companies (SME) – largely dominant in Europe (up to 99%)–, because their internal resources are limited. Since a few years, these facts lead governments to undertake actions aimed to create environments that boost inter-firm linkages and entrepreneurial clusters. In European countries, su…
Private Equity Investors as Matchmakers: Alliance Formation between PE-backed firms
2016
International audience; Alliances as long term inter-firm cooperation are seen as an important factor of economic growth. They are particularly important for small to medium sized companies whose internal resources are scarce. This article analyses the role of Private Equity Firms that constitute a major source of financing for non-publicly traded small to medium sized companies, in the formation of alliances for their portfolio companies. While previous studies analyse the question in the light of mainstream theories, we rely on the dual theory of the firm, combining the contractual/mainstream view and the knowledge-based view. Contrary to the current literature, our study does not rely on…
The role of Private Equity-firms in the formation of strategic alliances
2014
This research analyses the role of Private Equity firms in the formation of strategic alliances within the field of the French Private Equity market. We start to provide evidence of its importance from new survey information, before offering an explanation of the organizational phenomenon. The study addresses the questions of how and why Private Equity firms act as relational intermediaries to help their portfolio companies form alliances. Both questions are investigated in the light of the Private Equity firms’ contribution to the value creation process that comes with alliance formation. Answers are provided by means of three jointly used theoretical frameworks: (1) mainstream theories (t…
The role of Private Equity-firms in the formation of strategic alliances
2014
This research analyses the role of Private Equity firms in the formation of strategic alliances within the field of the French Private Equity market. We start to provide evidence of its importance from new survey information, before offering an explanation of the organizational phenomenon. The study addresses the questions of how and why Private Equity firms act as relational intermediaries to help their portfolio companies form alliances. Both questions are investigated in the light of the Private Equity firms’ contribution to the value creation process that comes with alliance formation. Answers are provided by means of three jointly used theoretical frameworks: (1) mainstream theories (t…
Mapping nonlinear gravity into General Relativity with nonlinear electrodynamics
2018
We show that families of nonlinear gravity theories formulated in a metric-affine approach and coupled to a nonlinear theory of electrodynamics can be mapped into General Relativity (GR) coupled to another nonlinear theory of electrodynamics. This allows to generate solutions of the former from those of the latter using purely algebraic transformations. This correspondence is explicitly illustrated with the Eddington-inspired Born-Infeld theory of gravity, for which we consider a family of nonlinear electrodynamics and show that, under the map, preserve their algebraic structure. For the particular case of Maxwell electrodynamics coupled to Born-Infeld gravity we find, via this corresponden…