89 research outputs found
Extremely Low Loss Phonon-Trapping Cryogenic Acoustic Cavities for Future Physical Experiments
Low loss Bulk Acoustic Wave devices are considered from the point of view of
the solid state approach as phonon-confining cavities. We demonstrate effective
design of such acoustic cavities with phonon-trapping techniques exhibiting
extremely high quality factors for trapped longitudinally-polarized phonons of
various wavelengths. Quality factors of observed modes exceed 1 billion, with a
maximum -factor of 8 billion and product of at
liquid helium temperatures. Such high sensitivities allow analysis of intrinsic
material losses in resonant phonon systems. Various mechanisms of phonon losses
are discussed and estimated
Reduction of helium permeation in microfabricated cells using aluminosilicate glass substrates and AlO coatings
The stability and accuracy of atomic devices can be degraded by the evolution
of their cell inner atmosphere. Hence, the undesired entrance or leakage of
background or buffer gas, respectively, that can permeate through the cell
walls, should be slowed down. In this work, we investigate helium permeation in
microfabricated alkali vapor cells filled with He and whose windows are made of
borosilicate glass (BSG) or aluminosilicate glass (ASG). The permeation is then
derived from routine measurements of the pressure-shifted hyperfine transition
frequency of an atomic clock. We first confirm that ASG reduces He permeation
rate by more than two orders of magnitude, in comparison with BSG. In addition,
we demonstrate that AlO thin-film coatings, known to avoid alkali
consumption in vapor cells, can also significantly reduce He permeation. The
permeation through BSG is thereby reduced by a factor 110 whereas the one
through ASG is decreased by a factor up to 5.8 compared to uncoated substrates.
These results may contribute to the development of miniaturized atomic clocks
and sensors with improved long-term stability or sensitivity.Comment: 7 pages, 5 figure
The material soul: Strategies for naturalising the soul in an early modern epicurean context
We usually portray the early modern period as one characterised by the âbirth of subjectivityâ with Luther and Descartes as two alternate representatives of this radical break with the past, each ushering in the new era in which âIâ am the locus of judgements about the world. A sub-narrative called âthe mind-body problemâ recounts how Cartesian dualism, responding to the new promise of a mechanistic science of nature, âsplit offâ the world of the soul/mind/self from the world of extended, physical substanceâa split which has preoccupied the philosophy of mind up until the present day. We would like to call attention to a different constellation of textsâneither a robust âtraditionâ nor an isolated âepisodeâ, somewhere in betweenâwhich have in common their indebtedness to, and promotion of an embodied, Epicurean approach to the soul. These texts follow the evocative hint given in Lucretiusâ De rerum natura that âthe soul is to the body as scent is to incenseâ (in an anonymous early modern French version). They neither assert the autonomy of the soul, nor the dualism of body and soul, nor again a sheer physicalism in which âintentionalâ properties are reduced to the basic properties of matter. Rather, to borrow the title of one of these treatises (LâĂme MatĂ©rielle), they seek to articulate the concept of a material soul. We reconstruct the intellectual development of a corporeal, mortal and ultimately material soul, in between medicine, natural philosophy and metaphysics, including discussions of Malebranche and Willis, but focusing primarily on texts including the 1675 Discours anatomiques by the Epicurean physician Guillaume Lamy; the anonymous manuscript from circa 1725 entitled LâĂme MatĂ©rielle, which is essentially a compendium of texts from the later seventeenth century (Malebranche, Bayle) along with excerpts from Lucretius; and materialist writings such Julien Offray de La Mettrieâs LâHomme-Machine (1748), in order to articulate this concept of a âmaterial soulâ with its implications for notions of embodiment, materialism and selfhood
An English cover-up: masks, murders, and English cruelty in Goncourt, Lorrain, and Schwob
Fin-de-siĂšcle writers from diverse disciplines were drawn to the seductive potential of masks and disguise; mask-wearing characters of indefinite identity, indeterminate gender, and insecure psychology proliferate in their texts. However, when characters are designated as English in such stories, they are also, and with remarkable frequency, associated with cruelty or murder: the mask-wielding murderers of Marcel Schwobâs âMM. Burke et Hare, Assassinsâ carry out their crimes in Britain upon British victims; Edmond de Goncourt weaves his theatrical narrative around the mask-like demeanour of Lord Annandale in La Faustin; and Jean Lorrainâs malicious Lord Ethal exacerbates the Duc de FrĂ©neuseâs perverse obsessions with masks in Monsieur de Phocas. This article explores this unexpected correlation, and examines the ways that English masks are used as narrative devices â at once to mould and play with national distinctions, and to reflect upon the psychological state of the French subject
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