Measurements of mechanical Q in levitated paramagnetic crystals

Thermal noise from test masses, arising both from internal noise in the test mass material and from losses in the suspension wires and their attachments, is a significant factor limiting sensitivity of interferometric gravity-wave detectors. To investigate ways of reducing these noise sources we are using magnetic levitation in place of suspension wires. A search for high-Q crystals with magnetic properties allowing tests in moderate field strengths has led us to paramagnetic crystals, and we report preliminary results with small levitated samples of Gadolinium Gallium Garnet (GGG) and Terbium Gallium Garnet (TGG). The technique seems the first to allow Q measurements with no mechanical contact, and may facilitate work aimed at reducing thermal noise

Coherent addition of two dimensional array of fiber lasers

Configurations for efficient free space coherent addition of four separate fiber lasers arranged in two dimensional array are presented. They include compact and robust interferometric combiners that can be inserted either inside or outside the cavity of the combined lasers system. The results reveal that over 85% combining efficiency can be obtained.Comment: To be published in Optics Communicatio

A Theory of (In)justice: The Failure of Tort Law to Secure Equal Respect for Women and a Feminist Contractarian Framework for Reform

Traditional approaches to philosophical theories of tort law have systematically undermined the individual worth and security interests of women. However, torts also provide a particularly powerful avenue for reform, in that they embody the public power of private law and offer individuals the opportunity to seek recourse and accountability for wrongs. In this paper, I offer a framework for such reformist approaches to tort philosophy, predominantly inspired by Jean Hampton’s “Feminist Contractarianism,” which requires that women be recognized as individuals with intrinsic worth who are deserving of respect. To accomplish this, I first note the particular relevance of social contract theory to tort philosophy, in the sense that both fields aim to establish and uphold fair terms of just and reasonable interaction among individuals. I then engage with the various deficiencies, both in classical social contract theory and in instrumentalist and non-instrumentalist theories of tort law, to adequately recognize women as individuals and to protect their corresponding security interests. I utilize scholarship by Martha Chamallas & Jennifer Wriggins to examine the relevance of these deficiencies in torts regarding domestic violence and sexual harassment cases, and assert that although non-instrumentalist theories provide the best framework for affirming individual worth, they have still historically failed to do so in the case of harms against women. Finally, I provide a framework for reform, based in respect for individual worth, dignity, and self-mastery consistent with the aims of non-instrumentalist approaches, that explicitly upholds protections for women – potentially with broader implications for other marginalized groups

Ejection Energy of Photoelectrons in Strong Field Ionization

We show that zero ejection energy of the photoelectrons is classically impossible for hydrogen-like ions, even when field ionization occurs adiabatically. To prove this we transform the basic equations to those describing two 2D anharmonic oscillators. The same method yields an alternative way to derive the anomalous critical field of hydrogen-like ions. The analytical results are confirmed and illustrated by numerical simulations. PACS Number: 32.80.RmComment: 7 pages, REVTeX, postscript file including the figures is available at http://www.physik.th-darmstadt.de/tqe/dieter/publist.html or via anonymous ftp from ftp://tqe.iap.physik.th-darmstadt.de/pub/dieter/publ_I_pra_pre.ps, accepted for publication in Phys. Rev.

Many-electron tunneling in atoms

A theoretical derivation is given for the formula describing N-electron ionization of atom by a dc field and laser radiation in tunneling regime. Numerical examples are presented for noble gases atoms.Comment: 11 pages, 1 EPS figure, submitted to JETP (Jan 99