Interaction of Ultracold Antihydrogen with a Conducting Wall

Abstract

We investigate the interaction of ultracold antihydrogen with a conducting surface. Our discussion focuses on the physical regime where the phenomenon of quantum reflection manifests. We calculate the reflection probability as function of incident atom energy. We find that, for ground state $\bar{H}$ atoms (with $T<10^{-5}$ K), the probability of reflection is $R\simeq 1-kb$, where $k$ is the momentum of the atom and $b=2174.0$ a.u. is a constant determined solely by the van der Waals-Casimir tail of the atom-wall interaction. We show that quantum reflection, which suppresses the direct contact of ultra-cold atoms with the surface, allows for the possibility of confinement and storage of cold antihydrogen atoms. We calculate the life-time of confinement as a function of antihydrogen energy. We develop a theory of $\bar{H}$ in a wave-guide and propose its application to fundamental measurements. In particular, for measurement of retardation corrections in the long-range component of the antiatom - wall potential. We demonstrate, for $\bar{H}$ falling in the gravitational field of Earth onto a conducting surface, the existence of quantized $\bar{H}$ states. We calculate that the lifetime of ultracold $\bar{H}$ in its lowest gravitational state and obtain $\tau =(Mgb/2\hslash {)}^{-1}\simeq 0.1$ s, where $Mg$ is a gravitational force acting on the antiatom. We propose that measurement of this lifetime may provide a new test for the gravitational properties of antimatter.

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• Casimir effects in atomic, molecular, and optical physics
• Whispering Gallery States of Antihydrogen
• Casimir-Polder shifts on quantum levitation states
• Quantum reflection of antihydrogen from a liquid helium film
• Quantum reflection and Liouville transformations from wells to walls
• Resonant Phenomena in Antihydrogen-Hydrogen Scattering
• Quantum ballistic experiment on antihydrogen fall
• Liouville transformations and quantum reflection
• Tuning quantum reflection in graphene with an external magnetic field
• Resonance spectroscopy of gravitational states of antihydrogen
• A spectroscopy approach to measure the gravitational mass of antihydrogen
• Fluctuations of the Casimir potential above a disordered medium
• Quenching of antihydrogen gravitational states by surface charges
• Statistical approach to Casimir-Polder potentials in heterogeneous media
• Quantum Reflection of Antihydrogen in the GBAR Experiment
• Quenching of $para$-H${}_2$ with an ultra-cold anti-hydrogen atom ${\bar{H}}_{1s}$