Dorian Gangloff

Quantization of energy is a quintessential characteristic of quantum systems. Here we analyze its effects on the operation of Otto cycle heat machines and show that energy quantization alone may alter and increase machine performance in terms of output power, efficiency, and even operation mode. Our results demonstrate that quantum thermodynamics enable the realization of classically inconceivable Otto machines, such as those with an incompressible working fluid. We propose to measure these effects experimentally using a laser-cooled trapped ion as a microscopic heat machine.

A trapped ion transported along a periodic potential is studied as a paradigmatic nanocontact frictional interface. The combination of the periodic corrugation potential and a harmonic trapping potential creates a one-dimensional energy landscape with multiple local minima, corresponding to multistable stick-slip friction. We measure the probabilities of slipping to the various minima for various corrugations and transport velocities. The observed probabilities show that the multislip regime can be reached dynamically at smaller corrugations than would be possible statically, and can be described by an equilibrium Boltzmann model. While a clear microscopic signature of multislip behavior is observed for the ion motion, the frictional force and dissipation are only weakly affected by the transition to multistable potentials.

Scaling-up from prototype systems to dense arrays of ions on chip, or vast networks of ions connected by photonic channels, will require developing entirely new technologies that combine miniaturized ion trapping systems with devices to capture, transmit and detect light, while refining how ions are confined and controlled. Building a cohesive ion system from such diverse parts involves many challenges, including navigating materials incompatibilities and undesired coupling between elements. Here, we review our recent efforts to create scalable ion systems incorporating unconventional materials such as graphene and indium tin oxide, integrating devices like optical fibers and mirrors, and exploring alternative ion loading and trapping techniques.

We report the localization of an ion by a one-dimensional optical lattice in the presence of an applied external force. The ion is confined radially by a radiofrequency trap and axially by a combined electrostatic and optical-lattice potential. The ion is cooled using a resolved Raman sideband technique to a mean vibrational number <n> = 0.6 \pm 0.1 along the optical lattice. We implement a detection method to monitor the position of the ion subject to a periodic electrical driving force with a resolution down to λ/40, and demonstrate suppression of the driven ion motion and localization to a single lattice site on time scales of up to 10 milliseconds. This opens new possibilities for studying many-body systems with long-range interactions in periodic potentials.

We present a novel hybrid system where an optical cavity is integrated with a microfabricated planar-electrode ion trap. The trap electrodes produce a tunable periodic potential allowing the trapping of up to 50 separate ion chains spaced by 160 $μ$m along the cavity axis. Each chain can contain up to 20 individually addressable Yb\textsuperscript{+} ions coupled to the cavity mode. We demonstrate deterministic distribution of ions between the sites of the electrostatic periodic potential and control of the ion-cavity coupling. The measured strength of this coupling should allow access to the strong collective coupling regime with $\lesssim$10 ions. The optical cavity could serve as a quantum information bus between ions or be used to generate a strong wavelength-scale periodic optical potential.