106 research outputs found
Non-linear spectroscopy of rubidium: An undergraduate experiment
In this paper, we describe two complementary non-linear spectroscopy methods
which both allow to achieve Doppler-free spectra of atomic gases. First,
saturated absorption spectroscopy is used to investigate the structure of the
transition in rubidium. Using a slightly
modified experimental setup, Doppler-free two-photon absorption spectroscopy is
then performed on the transition in
rubidium, leading to accurate measurements of the hyperfine structure of the
energy level. In addition, electric dipole selection rules of
the two-photon transition are investigated, first by modifying the polarization
of the excitation laser, and then by measuring two-photon absorption spectra
when a magnetic field is applied close to the rubidium vapor. All experiments
are performed with the same grating-feedback laser diode, providing an
opportunity to compare different high resolution spectroscopy methods using a
single experimental setup. Such experiments may acquaint students with quantum
mechanics selection rules, atomic spectra and Zeeman effect.Comment: 16 pages, 8 figure
Self-Consistent Quasi-Particle RPA for the Description of Superfluid Fermi Systems
Self-Consistent Quasi-Particle RPA (SCQRPA) is for the first time applied to
a more level pairing case. Various filling situations and values for the
coupling constant are considered. Very encouraging results in comparison with
the exact solution of the model are obtained. The nature of the low lying mode
in SCQRPA is identified. The strong reduction of the number fluctuation in
SCQRPA vs BCS is pointed out. The transition from superfluidity to the normal
fluid case is carefully investigated.Comment: 23 pages, 18 figures and 1 table, submitted to Phys. Rev.
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New Ways of Being a Man: "Positive" Hegemonic Masculinity in Meditation-based Communities of Practice
Connell’s concept of hegemonic masculinity is often reduced to a singular construct, consisting of “toxic” traits viewed as detrimental to well-being. However, the concept allows for variation in hegemony, including the possibility of forms more conducive to well-being. Through in-depth interviews with thirty male meditators in the United Kingdom, we explored the social dimensions of meditation practice to examine its potential implications for well-being. Most participants became involved with “communities of practice” centered on meditation that promoted new local hegemonies, and these included ideals experienced as conducive to well-being, like abstinence. However, social processes associated with hegemony, like hierarchy and marginalization, were not overturned. Moreover, participants faced challenges enacting new practices in relation to the broader system of hegemonic masculinity—outside these communities—reporting censure. Our findings are cautionary for professionals seeking to encourage well-being behaviors: that is, there is potential for adaptation in men, yet complex social processes influence this change
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