Erbium Lab

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Phases of matter are conventionally distinguished from one another by local observables. Topological quantum phases lie outside this paradigm; their differences can only be learned by examining them globally. This has striking implications for the stability of these phases, their classification, and the phase transitions between them. In this work, we experimentally demonstrate these implications using interacting magnetic erbium atoms in an optical lattice. We show that a Mott insulator and a pinned charge-density wave in one dimension are in distinct crystalline symmetry-protected topological phases (CSPTs). The quantum phase transition separating them is revealed by measuring nonlocal string order parameters using site-resolved imaging. Remarkably, stacking two copies of these states eliminates the critical point – a signature feature of topological phases that underlies their classification. Moreover, we show that while a programmable symmetry-breaking disorder pattern can also remove this critical point, averaging over disorder restores it, supporting recent theoretical predictions of mixed-state order. Finally, we highlight a connection between one of these CSPTs and the Haldane insulator, and detect signatures of the transition between the Haldane and the Mott insulator. Our results establish a path toward probing broader symmetry-protected topology and mixed-state order in programmable quantum devices.

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High-resolution fluorescence imaging of ultracold atoms and molecules is paramount to performing quantum simulation and computation in optical lattices and tweezers. Imaging durations in these experiments typically range from a millisecond to a second, significantly limiting the cycle time. In this work, we present fast, 2.4 μs single-atom imaging in lattices, with 99.4% fidelity - pushing the readout duration of neutral atom quantum platforms to be close to that of superconducting qubit platforms. Additionally, we thoroughly study the performance of accordion lattices. We also demonstrate number-resolved imaging without parity projection, which will facilitate experiments such as the exploration of high-filling phases in the extended Bose-Hubbard models, multi-band or SU(N) Fermi-Hubbard models, and quantum link models.

Entanglement can improve the measurement precision of quantum sensors beyond the shot noise limit. Neutral atoms, the basis of some of the most precise and accurate optical clocks and interferometers, do not naturally exhibit all-to-all interactions that are traditionally used to generate such entangled states. Instead, we take advantage of the magnetic dipole-dipole interaction native to most neutral atoms to realize spin-squeezed states. We achieve 7.1 dB of metrologically useful squeezing using the finite-range spin exchange interactions in an erbium quantum gas microscope. We further propose and demonstrate that introducing atomic motion protects the spin sector coherence at low fillings, significantly improving the achievable spin squeezing in a 2D dipolar system. This work’s protocol can be implemented with most neutral atoms, opening the door to quantum-enhanced metrology in other itinerant dipolar systems, such as molecules or optical lattice clocks, and serves as a novel method for studying itinerant quantum magnetism with long-range interactions.

In quantum mechanical many-body systems, long-range and anisotropic interactions promote rich spatial structure and can lead to quantum frustration, giving rise to a wealth of complex, strongly correlated quantum phases. Long-range interactions play an important role in nature; however, quantum simulations of lattice systems have largely not been able to realize such interactions. A wide range of efforts are underway to explore long-range interacting lattice systems using polar molecules, Rydberg atoms, optical cavities, and magnetic atoms. Here, we realize novel quantum phases in a strongly correlated lattice system with long-range dipolar interactions using ultracold magnetic erbium atoms. As we tune the dipolar interaction to be the dominant energy scale in our system, we observe quantum phase transitions from a superfluid into dipolar quantum solids, which we directly detect using quantum gas microscopy. Controlling the interaction anisotropy by orienting the dipoles enables us to realize a variety of stripe ordered states. Furthermore, by transitioning non-adiabatically through the strongly correlated regime, we observe the emergence of a range of metastable stripe-ordered states. This work demonstrates that novel strongly correlated quantum phases can be realized using long-range dipolar interaction in optical lattices, opening the door to quantum simulations of a wide range of lattice models with long-range and anisotropic interactions.

Realizing faster experimental cycle times is important for the future of quantum simulation. The cycle time determines how often the many-body wave-function can be sampled, defining the rate at which information is extracted from the quantum simulation. We demonstrate a system which can produce a Bose-Einstein condensate of 8×10^4 168Er atoms with approximately 85% condensate fraction in 800 ms and a degenerate Fermi gas of 167Er in 4 seconds, which are unprecedented times compared to many existing quantum gas experiments. This is accomplished by several novel cooling techniques and a tunable dipole trap. The methods used here for accelerating the production of quantum degenerate gases should be applicable to a variety of atomic species and are promising for expanding the capabilities of quantum simulation.