Atomic Physics
A low energy particle confined by a horizontal reflective surface and gravity settles in gravitationally bound quantum states. These gravitational quantum states (GQS) were so far only observed with neutrons. However, the existence of GQS…
Momentum-space nonsymmorphic symmetries, stemming from the projective algebra of synthetic gauge fields, can modify the manifold of the Brillouin zone and lead to a variety of topological phenomena. We present an acoustic realization of…
Since the early days of quantum mechanics hydrogen, as the simplest of all atoms, has been studied or used to investigate new physics. In parallel, this knowledge leads to different applications, e.g. a spin filter to separate metastable…
Air-lasing from single ionized N$_2^+$ molecules induced by laser filamentation in air has been intensively investigated and the mechanisms responsible for lasing are currently highly debated. We use ultrafast nitrogen K-edge spectroscopy…
A static electric field of a few V/cm shifts the energy levels of ultracold Rydberg atoms in a magneto-optical trap. For a given principle quantum number, most of the energy levels are nearly degenerate at zero field and fan out with…
Atoms constitute promising quantum sensors for a variety of scenarios including vacuum metrology. Key to this application is knowledge of the collision rate coefficient of the sensor atom with the particles being detected. Prior work…
We investigate the role of relativity in photo ionization of hydrogen-like ions by a laser pulse. For hydrogen, the wavelengths of the laser resides in the weakly ultra violet region. For higher nuclear charges, the laser parameters are…
Many powerful tests of the Standard Model of particle physics and searches for new physics with precision atomic spectroscopy are plagued by our lack of knowledge of nuclear properties. Ideally, such properties may be derived from precise…
While Rydberg atoms have shown tremendous potential to serve as accurate and sensitive detectors of microwaves and millimeter waves, their response is generally limited to a single narrow frequency band around a chosen microwave transition.…
In the process of interatomic Coulombic electron capture, an incident free electron is captured at an atomic center $A$ and the transition energy is transferred radiationlessly over a rather large distance to a neighboring atom $B$ of…
We experimentally demonstrate a cavity-based detection scheme for a cold atomic ensemble with a radiatively open transition. Our method exploits the collective strong coupling of atoms to the cavity mode, which results in off-resonant…
Optical atomic clocks$^{1,2}$ use electronic energy levels to precisely keep track of time. A clock based on nuclear energy levels promises a next-generation platform for precision metrology and fundamental physics studies. Thorium-229…
We report numerically exact quantum scattering calculations on magnetic Feshbach resonances in ultracold, strongly anisotropic atom-molecule [Rb($^2$S) + SrF($^2\Sigma^+$)] collisions based on state-of-the-art ab initio potential energy…
The onset of collision dynamics between an ion and a Rydberg atom is studied in a regime characterized by a multitude of collision channels. These channels arise from coupling between a non-polar Rydberg state and numerous highly polar…
We report a precise measurement of the isotope shifts in the $4^2$S$_{1/2} \rightarrow 3^2$D$_{3/2}$ electric quadrupole transition at 732~nm in $^{40 - 42,44,48}$Ca$^+$ via high-resolution laser spectroscopy of co-trapped ions, finding…
Neutral atoms trapped in the evanescent optical potentials of nanotapered optical fibers are a promising platform for developing quantum technologies and exploring fundamental science, such as quantum networks and quantum electrodynamics.…
Predicting magic wavelengths accurately requires precise knowledge of electric-dipole matrix elements of nearby atomic transitions. As a result, measurements of magic wavelengths allow us to test theoretical predictions for the matrix…
Machine learning is becoming a widely used technique with a impressive growth due to the diversity of problem of societal interest where it can offer practical solutions. This increase of applications and required resources start to become…
We propose and numerically benchmark light-pulse atom interferometry with ultra-cold quantum gases as a platform to test the modulo-square hypothesis of Born's rule. Our interferometric protocol is based on a combination of double Bragg and…
Cold cations, electrons and anions are ubiquitous in space, participate in star formation chemistry and are relevant to studies on the origin of molecular biology homochirality. We report on a system to generate and trap these species in…