Giacomo Cappellini

Direct Observation of Coherent Interorbital Spin-Exchange Dynamics

We report on the first direct observation of fast spin-exchange coherent oscillations between different long-lived electronic orbitals of ultracold 173Yb fermions. We measure, in a model-independent way, the strength of the exchange interaction driving this coherent process. This observation allows us to retrieve important information on the interorbital collisional properties of 173Yb atoms and paves the way to novel quantum simulations of paradigmatic models of two-orbital quantum magnetism.

Observation of chiral edge states with neutral fermions in synthetic Hall ribbons

Visualizing edge states in atomic systems Visualizing edge states in atomic systems Simulating the solid state using ultracold atoms is an appealing research approach. In solids, however, the charged electrons are susceptible to an external magnetic field, which curves their trajectories and makes them skip along the edge of the sample. To observe this phenomenon with cold atoms requires an artificial magnetic field to have a similar effect on the neutral atoms (see the Perspective by Celi and Tarruell). Stuhl et al. obtained skipping orbits with bosonic atoms using a lattice that consisted of an array of atoms in one direction and three internal atomic spin states in the other. In a complementary experiment, Mancini et al. observed similar physics with fermionic atoms. Science, this issue pp. 1514 and 1510; see also p. 1450 Analogs of quantum-Hall-effect edge states are observed with fermionic ytterbium-173 atoms in a synthetic lattice. [Also see Perspective by Celi and Tarruell] Chiral edge states are a hallmark of quantum Hall physics. In electronic systems, they appear as a macroscopic consequence of the cyclotron orbits induced by a magnetic field, which are naturally truncated at the physical boundary of the sample. Here we report on the experimental realization of chiral edge states in a ribbon geometry with an ultracold gas of neutral fermions subjected to an artificial gauge field. By imaging individual sites along a synthetic dimension, encoded in the nuclear spin of the atoms, we detect the existence of the edge states and observe the edge-cyclotron orbits induced during quench dynamics. The realization of fermionic chiral edge states opens the door for edge state interferometry and the study of non-Abelian anyons in atomic systems.

A one-dimensional liquid of Fermions with tunable spin

The physics of one-dimensional many-body systems is rich but still insufficiently understood. An ultracold atom experiment investigates the behaviour of one-dimensional strongly correlated fermions with a tunable number of spin components.

Strongly Interacting Gas of Two-Electron Fermions at an Orbital Feshbach Resonance.

We report on the experimental observation of a strongly interacting gas of ultracold two-electron fermions with an orbital degree of freedom and magnetically tunable interactions. This realization has been enabled by the demonstration of a novel kind of Feshbach resonance occurring in the scattering of two (173)Yb atoms in different nuclear and electronic states. The strongly interacting regime at resonance is evidenced by the observation of anisotropic hydrodynamic expansion of the two-orbital Fermi gas. These results pave the way towards the realization of new quantum states of matter with strongly correlated fermions with an orbital degree of freedom.

Measuring absolute frequencies beyond the GPS limit via long-haul optical frequency dissemination

Global Positioning System (GPS) dissemination of frequency standards is ubiquitous at present, providing the most widespread time and frequency reference for the majority of industrial and research applications worldwide. On the other hand, the ultimate limits of the GPS presently curb further advances in high-precision, scientific and industrial applications relying on this dissemination scheme. Here, we demonstrate that these limits can be reliably overcome even in laboratories without a local atomic clock by replacing the GPS with a 642-km-long optical fiber link to a remote primary caesium frequency standard. Through this configuration we stably address the 1S0-3P0 clock transition in an ultracold gas of 173Yb, with a precision that exceeds the possibilities of a GPS-based measurement, dismissing the need for a local clock infrastructure to perform beyond-GPS high-precision tasks. We also report an improvement of two orders of magnitude in the accuracy on the transition frequency reported in literature.

A compact ultranarrow high-power laser system for experiments with 578 nm ytterbium clock transition

In this paper, we present the realization of a compact, high-power laser system able to excite the ytterbium clock transition at 578 nm. Starting from an external-cavity laser based on a quantum dot chip at 1156 nm with an intra-cavity electro-optic modulator, we were able to obtain up to 60 mW of visible light at 578 nm via frequency doubling. The laser is locked with a 500 kHz bandwidth to an ultra-low-expansion glass cavity stabilized at its zero coefficient of thermal expansion temperature through an original thermal insulation and correction system. This laser allowed the observation of the clock transition in fermionic (173)Yb with a <50 Hz linewidth over 5 min, limited only by a residual frequency drift of some 0.1 Hz/s.

State-dependent interactions in ultracold 174Yb probed by optical clock spectroscopy

We report on the measurement of the scattering properties of ultracold

Realization of strongly interacting Fermi gases and spin-orbit coupled systems with an optical clock transition

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Synthetic dimensions and spin-orbit coupling with an optical clock transition

Yb bosons in a three-dimensional (3D) optical lattice. Site occupancy in an atomic Mott insulator is resolved with high-precision spectroscopy on an ultranarrow optical clock transition. Scattering lengths and loss rate coefficients for

Erratum: Direct Observation of Coherent Interorbital Spin-Exchange Dynamics [Phys. Rev. Lett.113, 120402 (2014)]

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