Abstract. Atoms formed in highly-magnetized, cryogenic Penning trap plasmas, such as those used in the Athena and ATRAP antihydrogen experiments, form in the guiding-center atom regime. In this regime, the positron orbit is well described by classical guiding-center drift dynamics. Electromagnetic radiation from such atoms is minimal, and energy loss is accomplished primarily through collisions between the atom and free positrons. With Fokker-Planck theory and Monte-Carlo simulation, we calculate the mean energy change an ensemble of such atoms experiences after the atom has been formed. Using this result, we show that the bulk of atoms formed in antihydrogen experiments do not relax out of the guiding-center regime to binding energies where radiation can become important.Abstract. Atoms formed in highly-magnetized, cryogenic Penning trap plasmas, such as those used in the Athena and ATRAP antihydrogen experiments, form in the guiding-center atom regime. In this regime, the positron orbit is well described by classical guiding-center drift dynamics. Electromagnetic radiation from such atoms is minimal, and energy loss is accomplished primarily through collisions between the atom and free positrons. With Fokker-Planck theory and Monte-Carlo simulation, we calculate the mean energy change an ensemble of such atoms experiences after the atom has been formed. Using this result, we show that the bulk of atoms formed in antihydrogen experiments do not relax out of the guiding-center regime to binding energies where radiation can become important.

AIP conference proceedingsJan 1, 20061 citation

Relaxation Oscillations, Stability, and Cavity Feedback in a Superradiant Raman Laser

Justin Bohnet, Zilong Chen, Joshua M. Weiner +2 more

We experimentally study the relaxation oscillations and amplitude stability properties of an optical laser operating deep into the bad-cavity regime using a laser-cooled ^{87}Rb Raman laser. By combining measurements of the laser light field with nondemolition measurements of the atomic populations, we infer the response of the gain medium represented by a collective atomic Bloch vector. The results are qualitatively explained with a simple model. Measurements and theory are extended to include the effect of intermediate repumping states on the closed-loop stability of the oscillator and the role of cavity feedback on stabilizing or enhancing relaxation oscillations. This experimental study of the stability of an optical laser operating deep into the bad-cavity regime will guide future development of superradiant lasers with ultranarrow linewidths.We experimentally study the relaxation oscillations and amplitude stability properties of an optical laser operating deep into the bad-cavity regime using a laser-cooled ^{87}Rb Raman laser. By combining measurements of the laser light field with nondemolition measurements of the atomic populations, we infer the response of the gain medium represented by a collective atomic Bloch vector. The results are qualitatively explained with a simple model. Measurements and theory are extended to include the effect of intermediate repumping states on the closed-loop stability of the oscillator and the role of cavity feedback on stabilizing or enhancing relaxation oscillations. This experimental study of the stability of an optical laser operating deep into the bad-cavity regime will guide future development of superradiant lasers with ultranarrow linewidths.

arXiv:1209.0774Physical Review LettersDec 18, 201240 citations

General Considerations on Relaxation

Pure and applied physicsJan 1, 19590 citations

Brief Review of Relaxation and Transport Theories

Jochen Gemmer B, Mathias Michel A, G. Mahler

Lecture notes in physicsJan 1, 20090 citations

Non-Markovian theory of resonant nonlinear-optical phenomena in the frequency domain

Masaki Aihara

The resonant nonlinear-optical phenomenon in condensed matter due to two-frequency excitation is investigated by a first-principles theory without using the phenomenological relaxation-time description. A new generalized nonlinear susceptibility is introduced in order to describe the non-Markovian process in the condensed phase associated with the resonant four-photon parametric effect. It is shown that the present non-Markovian version of the theory of the resonant Rayleigh-type optical mixing (RROM) naturally includes the resonant coherent anti-Stokes Raman scattering (RCARS) as the memory effect of the reservoir. That is, the two phenomena PROM and RCARS are unified from the microscopic viewpoint. The general expressions for nonlinear susceptibility for RROM and RCARS are obtained by taking into consideration the frequency dependence of the transverse relaxation time ${T}_{2}$ . These provide us the general guide for the study of several relaxation phenomena in condensed materials by means of resonant coherent nonlinear-optical methods.The resonant nonlinear-optical phenomenon in condensed matter due to two-frequency excitation is investigated by a first-principles theory without using the phenomenological relaxation-time description. A new generalized nonlinear susceptibility is introduced in order to describe the non-Markovian process in the condensed phase associated with the resonant four-photon parametric effect. It is shown that the present non-Markovian version of the theory of the resonant Rayleigh-type optical mixing (RROM) naturally includes the resonant coherent anti-Stokes Raman scattering (RCARS) as the memory effect of the reservoir. That is, the two phenomena PROM and RCARS are unified from the microscopic viewpoint. The general expressions for nonlinear susceptibility for RROM and RCARS are obtained by taking into consideration the frequency dependence of the transverse relaxation time ${T}_{2}$. These provide us the general guide for the study of several relaxation phenomena in condensed materials by means of resonant coherent nonlinear-optical methods.

Physical review. B, Condensed matterMay 15, 19836 citations

{T}_{2}

. These provide us the general guide for the study of several relaxation phenomena in condensed materials by means of resonant coherent nonlinear-optical methods.