Abstract
We study the near-threshold molecular and collisional physics of a strong $^{40}$K p-wave Feshbach resonance through a combination of measurements, numerical calculations, and modeling. Dimer spectroscopy employs both radio-frequency spin-flip association in the MHz band and resonant association in the kHz band. Systematic uncertainty in the measured binding energy is reduced by a model that includes both the Franck-Condon overlap amplitude and inhomogeneous broadening. Coupled-channels calculations based on mass-scaled $^{39}$K potentials compare well to the observed binding energies and also reveal a low-energy p-wave shape resonance in the open channel. Contrary to conventional expectation, we observe a nonlinear variation of the binding energy with magnetic field, and explain how this arises from the interplay of the closed-channel ramping state with the near-threshold shape resonance in the open channel. We develop an analytic two-channel model that includes both resonances as well as the dipole-dipole interactions which, we show, become important at low energy. Using this parameterization of the energy dependence of the scattering phase, we can classify the studied $^{40}$K resonance as broad. Throughout the paper, we compare to the well understood s-wave case, and discuss the significant role played by van der Waals physics. The resulting understanding of the dimer physics of p-wave resonances provides a solid foundation for future exploration of few- and many-body orbital physics.
Highlights
Strong p-wave interactions are rare in nature, so their extreme tunability in ultracold systems [1,2] is an opportunity for discovery [3,4,5]
We have used experimental and theoretical tools to probe the physics of ultracold p-wave collisions and near-threshold Feshbach dimer states
Through both numerical and analytical models, that the origin of the curvature is the interplay of the ramping closed-channel state with the near-threshold shape resonance in the open channel
Summary
Strong p-wave interactions are rare in nature, so their extreme tunability in ultracold systems [1,2] is an opportunity for discovery [3,4,5]. We perform association spectroscopy to determine the binding energies of p-wave Feshbach dimers near a strong resonance of 40K To explain these measurements, we offer an analytic treatment that builds on the commonly used effective-range approximation (ERA) of p-wave scattering [48,49,50,51,52], cot δ = −(V k3)−1 − (Rk)−1 + O{k},. Where Vbg is the background scattering volume, δB = B − B0, B is the magnetic field, B0 is the location of the resonance, and is its magnetic width We explain how this form emerges from the low-energy limit of a two-channel model in the broad- and narrow-resonance cases.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
