Local Observables in a Landscape of Infrared Gauge Modes

Cosmological local observables are at best statistically determined by the fundamental theory describing inflation. When the scalar inflaton is coupled uniformly to a collection of subdominant massless gauge vectors, rotational invariance is obeyed locally. However, the statistical isotropy of fluctuations is spontaneously broken by gauge modes whose wavelength exceed our causal horizon. This leads to a landscape picture where primordial correlators depend on the position of the observer. We compute the stochastic corrections to the curvature power spectrum, show the existence of a new local observable (the shape of the quadrupole), and constrain the theory using Planck limits.Comment: 5 pages, 3 figures, v2: minor updates, matches version published in Physics Letters

Stability of Horndeski vector-tensor interactions

We study the Horndeski vector-tensor theory that leads to second order equations of motion and contains a non-minimally coupled abelian gauge vector field. This theory is remarkably simple and consists of only 2 terms for the vector field, namely: the standard Maxwell kinetic term and a coupling to the dual Riemann tensor. Furthermore, the vector sector respects the U(1) gauge symmetry and the theory contains only one free parameter, M^2, that controls the strength of the non-minimal coupling. We explore the theory in a de Sitter spacetime and study the presence of instabilities and show that it corresponds to an attractor solution in the presence of the vector field. We also investigate the cosmological evolution and stability of perturbations in a general FLRW spacetime. We find that a sufficient condition for the absence of ghosts is M^2>0. Moreover, we study further constraints coming from imposing the absence of Laplacian instabilities. Finally, we study the stability of the theory in static and spherically symmetric backgrounds (in particular, Schwarzschild and Reissner-Nordstr\"om-de Sitter). We find that the theory, quite generally, do have ghosts or Laplacian instabilities in regions of spacetime where the non-minimal interaction dominates over the Maxwell term. We also calculate the propagation speed in these spacetimes and show that superluminality is a quite generic phenomenon in this theory.Comment: References adde

The ‘Dutch disease’ reexamined: Resource booms can benefit the wider economy

In the cases of Norway and Australia, there's evidence of productivity 'spillovers' between industries, write Hilde C. Bjørnland and Leif Anders Thorsru

Coordination Strategies When Working from Anywhere: A Case Study of Two Agile Teams

Effective coordination is the key to successful agile teams. They rely on frequent interactions and mutual adjustment to manage dependencies between activities, which traditionally has been solved by co-locating the team. As the world is adjusting to post-covid work-life, companies are moving towards a work-from-anywhere approach where workers can choose to what degree they want to work from home or office. However, little is known about coordination in such a context. We report findings on developers’ emerging strategies when working-from-anywhere, from an exploratory case study in Norway, including eight interviews. Our study shows that new strategies for mutual adjustment emerged as teams experimented with different tools and approaches: developers chose tasks according to location, tasks with vague requirements are performed collocated while individual tasks requiring focus are best performed at home; large meetings are virtual, preserving co-located time for collaborative tasks; using virtual rooms to maintain unscheduled meetings as they communicate mental presence to teammates, lowering the threshold for intra-team unscheduled talks. The strategies can help organizations create a productive and effective environment for developers.publishedVersio

Post-Newtonian methods and the gravito-electromagnetic analogy

In theoretical physics there is a well known analogy between general relativity and electrodynamics which is based on a linearization of Einstein's field equation. Such a kind of analogy is interesting since Einstein's equation (on component form) is extremely complicated mathematically and hard to gain physical insight into. It turns out though, that a lot of papers in the rich literature on the topic are in lack of a systematic method. The main purpose of this thesis is to study the analogy in a more consistent way using state of the art perturbative methods. The analysis is based on the socalled post-Newtonian approximation-scheme which provides a systematic way to expand any metric theory of gravity, and which also takes account for non-linear effects. By choosing suitable variables and gauge (coordinate) conditions, the post-Newtonian limit of general relativity is reformulated in a way which is appropriate for the discussion. The same kind of systematic expansion is also applied to electrodynamics. In this way the theories are compared in a consistent way beyond their lowest order approximations. This work, described in chapter 4, is basically just a comparison of the mathematical structure of the considered approximations of the theories. In the following chapter the perspective is extended by exploring the huge conceptual difference between the theories. Based on calculations the geometric significance of curvature in the post-Newtonian approximation of general relativity is investigated. The most interesting finding from this chapter is that the analogy turns out being stronger when gravitational phenomena are evaluated in a so-called local proper reference frame, which is quite interesting since in that case the theories are treated on a more equal footing conceptually

Course in coping with anxiety: a quantitative evaluation study

Masteroppgave psykisk helsearbeid, 2012Formål: Psykiske helseproblemer utgjør i dagens samfunn en betydelig folkehelseutfordring. I den norske befolkningen er angstlidelser en av de tre mest utbredte psykiske lidelsene. Prognoser viser at en fjerdedel av befolkningen vil få en angstlidelse i løpet av livet, og ca 15 % i løpet av ett år. En Østlandskommune har, i samarbeid med en annen kommune, utarbeidet et angstmestringskurs bygd opp rundt den kognitive modellen, egnet for mennesker med lettere til moderate angstplager. Målsettingen med kurset er at deltakerne skal mestre angsten bedre. Kommunen har gjennomført sju kurs, med til sammen 45 deltakere. Hensikten med studien er å gjøre en evaluering av angstmestringskurset. En evaluering kan bidra til å kvalitetssikre og videreutvikle intervensjonen i forhold til mennesker med lettere til moderate angstplager, som blir henvist til Avdeling psykisk helse i denne Østlandskommunen. Metode: Studien bruker kvantitativ metode. Dataene er samlet inn ved hjelp av et spørreskjema, i tillegg til et angstscoresskjema som ble fylt ut før kursstart, og etterpå i tidsrom av tre måneder til fire år. Data omfatter tilbakemeldinger om tema i kurset, nytteverdien av gruppedeltakelse og oppnådd målsetting. Til sammen deltok 31 informanter. I databehandlingen, ble de inndelt i fem grupper avhengig av starttidspunkt på kurs. Resultat: Resultatet viser at informantene var svært fornøyd med kurset. De hadde god utbytte av de ulike temaene, og aller best utbytte av den kognitive modellen og kunnskapsformidling om angst. Støtten og nytten av å være sammen med andre mennesker med angst, samt engasjerte kursledere, viser seg å være betydningsfullt. Informantene mestrer angsten i gjennomsnittlig middels grad ved undersøkelsestidspunktet. Pre – post angstscoreskjema viser signifikante endringer på angstsymptomer hos de fire siste gruppene. Konklusjon: Evalueringen viser at angstmestringskurs for mennesker med lettere til moderate angstplager kan være et viktig tiltak i primærhelsetjenesten. Langtidseffekten er noe usikker, med tanke på hva som virker. Nøkkelord: Mestring, Angst, psykoedukasjon, salutogenese, Kognitiv terapi, kognitive, behandlingsgruppe, empowerment