Harnessing Nth Root Gates for Energy Storage.

We explore the use of fractional controlled-not gates in quantum thermodynamics. The Nth-root gate allows for a paced application of two-qubit operations. We apply it in quantum thermodynamic protocols for charging a quantum battery.

Realization of a chip-based hybrid trapping setup for 87Rb atoms and Yb+ ion crystals.

Hybrid quantum systems integrate laser-cooled trapped ions and ultracold quantum gases within a single experimental configuration, offering vast potential for applications in quantum chemistry, polaron physics, quantum information processing, and quantum simulations. In this study, we introduce the development and experimental validation of an ion trap chip that incorporates a flat atomic chip trap directly beneath it. This innovative design addresses specific challenges associated with hybrid atom-ion traps by providing precisely aligned and stable components, facilitating independent adjustments of the depth of the atomic trapping potential, and positioning trapped ions.

Resonating Electrostatically Guided Electrons.

An essential component for quantum-enhanced measurements with free electrons is an electron resonator. We report stable guiding of free electrons at 50 eV energy for up to seven round trips in a linear autoponderomotive guiding structure, which is realized with two microstructured printed circuit boards that generate the required electromagnetic fields. Free electrons are laser triggered from a sharp tungsten needle tip and coupled in at the front of the electron resonator with the help of sub-nanosecond-fast switchable electron mirrors.

Trapped atoms in spatially-structured vector light fields.

Spatially-structured laser beams, eventually carrying orbital angular momentum, affect electronic transitions of atoms and their motional states in a complex way. We present a general framework, based on the spherical tensor decomposition of the interaction Hamiltonian, for computing atomic transition matrix elements for light fields of arbitrary spatial mode and polarization structures. We study both the bare electronic matrix elements, corresponding to transitions with no coupling to the atomic center-of-mass motion, as well as the matrix elements describing the coupling to the quantized atomic motion in the resolved side-band regime.