154 research outputs found
Arithmetic Spacetime Geometry from String Theory
An arithmetic framework to string compactification is described. The approach
is exemplified by formulating a strategy that allows to construct geometric
compactifications from exactly solvable theories at . It is shown that the
conformal field theoretic characters can be derived from the geometry of
spacetime, and that the geometry is uniquely determined by the two-dimensional
field theory on the world sheet. The modular forms that appear in these
constructions admit complex multiplication, and allow an interpretation as
generalized McKay-Thompson series associated to the Mathieu and Conway groups.
This leads to a string motivated notion of arithmetic moonshine.Comment: 36 page
Wave Number of Maximal Growth in Viscous Magnetic Fluids of Arbitrary Depth
An analytical method within the frame of linear stability theory is presented
for the normal field instability in magnetic fluids. It allows to calculate the
maximal growth rate and the corresponding wave number for any combination of
thickness and viscosity of the fluid. Applying this method to magnetic fluids
of finite depth, these results are quantitatively compared to the wave number
of the transient pattern observed experimentally after a jump--like increase of
the field. The wave number grows linearly with increasing induction where the
theoretical and the experimental data agree well. Thereby a long-standing
controversy about the behaviour of the wave number above the critical magnetic
field is tackled.Comment: 19 pages, 15 figures, RevTex; revised version with a new figure and
references added. submitted to Phys Rev
Tate Form and Weak Coupling Limits in F-theory
We consider the weak coupling limit of F-theory in the presence of
non-Abelian gauge groups implemented using the traditional ansatz coming from
Tate's algorithm. We classify the types of singularities that could appear in
the weak coupling limit and explain their resolution. In particular, the weak
coupling limit of SU(n) gauge groups leads to an orientifold theory which
suffers from conifold singulaties that do not admit a crepant resolution
compatible with the orientifold involution. We present a simple resolution to
this problem by introducing a new weak coupling regime that admits
singularities compatible with both a crepant resolution and an orientifold
symmetry. We also comment on possible applications of the new limit to model
building. We finally discuss other unexpected phenomena as for example the
existence of several non-equivalent directions to flow from strong to weak
coupling leading to different gauge groups.Comment: 34 page
Tidal dissipation within hot Jupiters: a new appraisal
Eccentricity or obliquity tides have been proposed as the missing energy
source that may explain the anomalously large radius of some transiting ``hot
Jupiters''. To maintain a non-zero and large obliquity, it was argued that the
planets can be locked in a Cassini state, i.e. a resonance between spin and
orbital precessions. We compute the tidal heating within ``inflated'' close-in
giant planets with a non-zero eccentricity or obliquity. We further inspect
whether the spin of a ``hot Jupiter'' could have been trapped and maintained in
a Cassini state during its early despinning and migration. We estimate the
capture probability in a spin-orbit resonance between 0.5 AU (a distance
where tidal effects become significant) and 0.05 AU for a wide range of secular
orbital frequencies and amplitudes of gravitational perturbations. Numerical
simulations of the spin evolution are performed to explore the influence of
tidal despinning and migration processes on the resonance stability. We find
that tidal heating within a non-synchronous giant planet is about twice larger
than previous estimates based on the hypothesis of synchronization. Chances of
capture in a spin-orbit resonance are very good around 0.5 AU but they decrease
dramatically with the semi-major axis. Furthermore, even if captured, both
tidal despinning and migration processes cause the tidal torque to become large
enough that the obliquity ultimately leaves the resonance and switches to near
. Locking a ``hot Jupiter'' in an isolated spin-orbit resonance is
unlikely at 0.05 AU but could be possible at larger distances. Another
mechanism is then required to maintain a large obliquity and create internal
heating through obliquity tidesComment: 4 pages & 2 Figure
Politicising government engagement with corporate social responsibility: âCSRâ as an empty signifier
Governments are widely viewed by academics and practitioners (and society more generally) as the key societal actors who are capable of compelling businesses to practice corporate social responsibility (CSR). Arguably, such government involvement could be seen as a technocratic device for encouraging ethical business behaviour. In this paper, we offer a more politicised interpretation of government engagement with CSR where âCSRâ is not a desired form of business conduct but an element of discourse that governments can deploy in structuring their relationships with other social actors. We build our argument through a historical analysis of government CSR discourse in the Russian Federation. Laclau and Mouffe's (Hegemony and socialist strategy: Towards a radical democratic politics,Verso Books, London, 1985) social theory of hegemony underpins our research. We find that âCSRâ in the Russian governmentâs discourse served to legitimise its power over large businesses. Using this case, we contribute to wider academic debates by providing fresh empirical evidence that allows the development of critical evaluation tools in relation to governmentsâ engagement with âCSRâ. We find that governments are capable of hijacking CSR for their own self-interested gain. We close the paper by reflecting on the merit of exploring the case of the Russian Federation. As a ânon-coreâ, non-western exemplar, it provides a useful âmirrorâ with which to reflect on the more widely used test-bed of Western industrial democracies when scrutinising CSR. Based on our findings, we invite other scholars to adopt a more critical, politicised stance when researching the role of governments in relation to CSR in other parts of the world
Justice and Corporate Governance: New Insights from Rawlsian Social Contract and Senâs Capabilities Approach
By considering what we identify as a problem inherent in the ânature of the firmââthe risk of abuse of authorityâwe propound the conception of a social contract theory of the firm which is truly Rawlsian in its inspiration. Hence, we link the social contract theory of the firm (justice at firmâs level) with the general theory of justice (justice at societyâs level). Through this path, we enter the debate about whether firms can be part of Rawlsian theory of justice showing that corporate governance principles enter the âbasic structure.â Finally, we concur with Senâs aim to broaden the realm of social justice beyond what he calls the âtranscendental institutional perfectionismâ of Rawlsâ theory. We maintain the contractarian approach to justice but introduce Senâs capability concept as an element of the constitutional and post-constitutional contract model of institutions with special reference to corporate governance. Accordingly, rights over primary goods and capabilities are (constitutionally) granted by the basic institutions of society, but many capabilities have to be turned into the functionings of many stakeholders through the operation of firms understood as post-constitutional institutional domains. The constitutional contract on the distribution of primary goods and capabilities should then shape the principles of corporate governance so that at post-constitutional level anyone may achieve her/his functionings in the corporate domain by exercising such capabilities. In the absence of such a condition, post-constitutional contracts would distort the process that descends from constitutional rights and capabilities toward social outcomes
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