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 $5{\rm S}_{1/2}\to 5{\rm P}_{3/2}$ transition in rubidium. Using a slightly modified experimental setup, Doppler-free two-photon absorption spectroscopy is then performed on the $5{\rm S}_{1/2}\to 5{\rm D}_{5/2}$ transition in rubidium, leading to accurate measurements of the hyperfine structure of the $5{\rm D}_{5/2}$ 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.

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