Analogue Casimir Radiation using an Optical Para- metric Oscillator

We establish an explicit analogy between the dynamical Casimir effect and the photon emission of a thin non-linear crystal pumped inside a cavity. This allows us to propose a system based on a type-I optical parametric oscillator (OPO) to simulate a cavity oscillating in vacuum at optical frequencies. The resulting photon flux is expected to be more easily detectable than with a mechanical excitation of the mirrors. We conclude by comparing different theoretical predictions and suggest that our experimental proposal could help discriminate between them.Comment: 7 pages, 2 figures, epl2 stylefile necessary to compil

Repulsive Casimir forces and the role of surface modes

The Casimir repulsion between a metal and a dielectric suspended in a liquid has been thoroughly studied in recent experiments. In the present paper we consider surface modes in three layered systems modeled by dielectric functions guaranteeing repulsion. It is shown that surface modes play a decisive role in this phenomenon at short separations. For a toy plasma model we find the contribution of the surface modes at all distances.Comment: 13 pages, 3 figures, submitted to PR

Nine protestants are to be esteemed worth ten catholics. Representing religion, labour and economic performance in pre-Industrial Europe, c.1650 - c.1800.

Religion was one of the factors that was frequently identified by seventeenth- and eighteenth-century economists as exerting an important influence on the pre-industrial European economies. These writers were especially interested in the economic effects of the Reformation on the economic perfomance of European countries. Nearly all authors argued that Protestantism and economic success were positively correlated. In this paper, the arguments of economic writers are reviewed with reference to the issue of religious holidays. This analysis shows that a high number of religious holidays, on which nearly all forms of manual labour was forbidden, were portrayed as detrimental to the economy.Religion; Economy; Max Weber; Protestant Ethic; Holidays; Leisure; History of Economic Thought; Mercantilism; Industrious Revolution; Work Hours

Unmarried adolescents and filial assistance in eighteenth-century Flanders

Service was one of the main characteristics of the European Marriage Pattern in pre-industrial western Europe. During this stage of the life cycle adolescents could acquire the material assets and skills that were required to marry and start an independent household. Whilst in service, servants could save between 40 and 60 per cent of their cash wage. This paper illustrates that servants also used their earnings to assist their families. Parents of servants in particular could rely on both remittances in cash and in kind. As such, placing children in service was also a source of income for peasant household in Flanders. I argue that both patterns of land ownership and the restricted access to welfare ressources explain why servants displayed this altruistic behaviour.adolescents, farm servants, saving, Flanders, family assistance, poor relief, household formation, European Marriage Pattern,

Roughness correction to the Casimir force : Beyond the Proximity Force Approximation

We calculate the roughness correction to the Casimir effect in the parallel plates geometry for metallic plates described by the plasma model. The calculation is perturbative in the roughness amplitude with arbitrary values for the plasma wavelength, the plate separation and the roughness correlation length. The correction is found to be always larger than the result obtained in the Proximity Force Approximation.Comment: 7 pages, 3 figures, v2 with minor change

Sample dependence of the Casimir force

We have analysed available optical data for Au in the mid-infrared range which is important for a precise prediction of the Casimir force. Significant variation of the data demonstrates genuine sample dependence of the dielectric function. We demonstrate that the Casimir force is largely determined by the material properties in the low frequency domain and argue that therefore the precise values of the Drude parameters are crucial for an accurate evaluation of the force. These parameters can be estimated by two different methods, either by fitting real and imaginary parts of the dielectric function at low frequencies, or via a Kramers–Kronig analysis based on the imaginary part of the dielectric function in the extended frequency range. Both methods lead to very similar results. We show that the variation of the Casimir force calculated with the use of different optical data can be as large as 5% and at any rate cannot be ignored. To have a reliable prediction of the force with a precision of 1%, one has to measure the optical properties of metallic films used for the force measurement

Collective Atomic Motion in an Optical Lattice formed inside a High Finesse Cavity

We report on collective non-linear dynamics in an optical lattice formed inside a high finesse ring cavity in a so far unexplored regime, where the light shift per photon times the number of trapped atoms exceeds the cavity resonance linewidth. We observe bistability and self-induced squeezing oscillations resulting from the retro-action of the atoms upon the optical potential wells. We can well understand most of our observations within a simplified model assuming adiabaticity of the atomic motion. Non-adiabatic aspects of the atomic motion are reproduced by solving the complete system of coupled non-linear equations of motion for hundred atoms.Comment: 4 pages, 5 figure

Comment on "Demonstration of the Casimir Force in the 0.6 to 6 micrometer Range"

We comment on a recently published measurement of the Casimir force for distances in the 0.6 to 6 micrometer range between two Au surfaces (Phys. Rev. Lett. 78, 5(1997)) and the net discrepancy reported for the comparison with theoretical predictions (Phys. Rev. Lett. 81, 5475 (1998)).Comment: 1 page, LaTeX, 2 encapsulated postscript figure