تقرير
Cross-calibration of atomic pressure sensors and deviation from quantum diffractive collision universality for light particles
| العنوان: | Cross-calibration of atomic pressure sensors and deviation from quantum diffractive collision universality for light particles |
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| المؤلفون: | Shen, Pinrui, Frieling, Erik, Herperger, Katherine R., Uhland, Denis, Stewart, Riley A., Deshmukh, Avinash, Krems, Roman V., Booth, James L., Madison, Kirk W. |
| سنة النشر: | 2022 |
| المجموعة: | Physics (Other) Quantum Physics |
| مصطلحات موضوعية: | Physics - Atomic Physics, Quantum Physics |
| الوصف: | The total room-temperature, velocity-averaged cross section for atom-atom and atom-molecule collisions is well approximated by a universal function depending only on the magnitude of the leading order dispersion coefficient, $C_6$. This feature of the total cross section together with the universal function for the energy distribution transferred by glancing angle collisions ($P_{\rm{QDU}6}$) can be used to empirically determine the total collision cross section and realize a self-calibrating, vacuum pressure standard. This was previously validated for Rb+N$_2$ and Rb+Rb collisions. However, the post-collision energy distribution is expected to deviate from $P_{\rm{QDU}6}$ in the limit of small $C_6$ and small reduced mass. Here we observe this deviation experimentally by performing a direct cross-species loss rate comparison between Rb+H$_2$ and Li+H$_2$ and using the \textit{ab initio} value of $\langle \sigma_{\rm{tot}} \, v \rangle_{\rm{Li+H}_2}$. We find a velocity averaged total collision cross section ratio, $R = \langle \sigma_{\rm{tot}} \, v \rangle_{\rm{Li+H}_2} : \langle \sigma_{\rm{tot}} \, v \rangle_{\rm{Rb+H}_2} = 0.83(5)$. Based on an \textit{ab initio} computation of $\langle \sigma_{\rm{tot}} \, v \rangle_{\rm{Li+H}_2} = 3.13(6)\times 10^{-15}$ m$^3$/s, we deduce $\langle \sigma_{\rm{tot}} \, v \rangle_{\rm{Rb+H}_2} = 3.8(2) \times 10^{-15}$ m$^3$/s, in agreement with a Rb+H$_2$ \textit{ab initio} value of $\langle \sigma_{\mathrm{tot}} v \rangle_{\mathrm{Rb+H_2}} = 3.57 \times 10^{-15} \mathrm{m}^3/\mathrm{s}$.By contrast, fitting the Rb+H$_2$ loss rate as a function of trap depth to the universal function we find $\langle \sigma_{\rm{tot}} \, v \rangle_{\rm{Rb+H}_2} = 5.52(9) \times 10^{-15}$ m$^3$/s. Finally, this work demonstrates how to perform a cross-calibration of sensor atoms to extend and enhance the cold atom based pressure sensor. Comment: 14 pages, 9 figures |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1088/1367-2630/acd46e |
| الوصول الحر: | http://arxiv.org/abs/2209.02900Test |
| رقم الانضمام: | edsarx.2209.02900 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1088/1367-2630/acd46e |
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