Mott-insulator phases of non-locally coupled 1D dipolar Bose gases

We analyze the Mott-insulator phases of dipolar bosonic gases placed in neighboring but unconnected 1D traps. Whereas for short-range interactions the 1D systems are independent, the non-local dipole-dipole interaction induces a direct Mott-insulator to pair-superfluid transition which significantly modifies the boundaries of the lowest Mott-insulator phases. The lowest boundary of the lowest Mott regions becomes progressively constant as a function of the hopping rate, eventually inverting its slope, leading to a re-entrant configuration which is retained in 2D. We discuss the consequences of this effect on the spatial Mott-insulator plateaux in experiments with additional harmonic confinement, showing that anti-intuitively the plateaux may become wider for increasing hopping. Our results are also applicable to non-dipolar boson-boson mixtures.Comment: 4 pages, 4 eps figures; minor changes, reference adde

Experimental Signatures of Fermiophobic Higgs bosons

The most general Two Higgs Doublet Model potential without explicit CP violation depends on 10 real independent parameters. Excluding spontaneous CP violation results in two 7 parameter models. Although both models give rise to 5 scalar particles and 2 mixing angles, the resulting phenomenology of the scalar sectors is different. If flavour changing neutral currents at tree level are to be avoided, one has, in both cases, four alternative ways of introducing the fermion couplings. In one of these models the mixing angle of the CP even sector can be chosen in such a way that the fermion couplings to the lightest scalar Higgs boson vanishes. At the same time it is possible to suppress the fermion couplings to the charged and pseudo-scalar Higgs bosons by appropriately choosing the mixing angle of the CP odd sector. We investigate the phenomenology of both models in the fermiophobic limit and present the different branching ratios for the decays of the scalar particles. We use the present experimental results from the LEP collider to constrain the models.Comment: 23 pages, 18 figures included, newer experimental data include

Demand, Production, and the Determinants of Distribution: A Caveat on "Wage-Led Growth"

The incomes of workers and capitalists pertain to different moments of accumulation. Wages are shares of capital outlays sustaining production; profits are shares of commodity sales. If aggregate demand and the scale of productive undertakings are shaped with a measure of mutual autonomy, the class distribution of income and the measure of economic activity are jointly determined by the same processes. In those settings “wage-led growth” has neither analytical nor policy purchase as associations between wage shares and levels of output (or growth) are confounded consequences of distinct effects on each measure of broader developments in the economy. A more appropriate dichotomy is that between “investment-led” and “consumption-led” growth, with the former resulting in comparatively higher wage shares. After advancing and illustrating these points, this paper motivates its approach to class income flows and the role of demand--which draw on the Circuit of Capital--in relation to the equivalent Kaleckian approaches sustaining arguments for “wage-led growth”

Phonon instability in two-dimensional dipolar Bose-Einstein Condensates

The partially attractive character of the dipole-dipole interaction leads to phonon instability in dipolar condensates, which is followed by collapse in three-dimensional geometries. We show that the nature of this instability is fundamentally different in two-dimensional condensates, due to the dipole-induced stabilization of two-dimensional bright solitons. As a consequence, a transient gas of attractive solitons is formed, and collapse may be avoided. In the presence of an harmonic confinement, the instability leads to transient pattern formation followed by the creation of stable two-dimensional solitons. This dynamics should be observable in on-going experiments, allowing for the creation of stable two-dimensional solitons for the first time ever in quantum gases.Comment: 4 pages, 4 figure