Various Scientific News

Category for scientific news not related to a particular group (E.g. single author papers).

Excitations of a two-dimensional supersolid

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Now published in the journal “Physical Review A”!  The newest work from the Theory group are the results of PhD student Elena Poli’s DK-ALM research stay abroad in the group of Professor Blair Blakie at the University of Otago, NZ. In this theory paper, they study the excitations and elastic parameters of the 2D supersolid state of a BEC with dipolar interactions and soft-core interactions. See the following excerpt from the abstract for some of the details of this collaborative effort:

[The] supersolid state has three gapless excitation branches arising from the spontaneously broken continuous symmetries. Two of these branches are related to longitudinal sound waves, similar to those in one-dimensional supersolids. The third branch is a transverse wave arising from the non-zero shear modulus of the two-dimensional crystal. We present the results of numerical calculations for the excitations and dynamic structure factor characterising the density fluctuations, and study their behavior across the discontinuous superfluid to supersolid transition. We show that the speeds of sound are described by a hydrodynamic theory that incorporates generalized elastic parameters, including the shear modulus. Furthermore, we establish that dipolar and soft-core supersolids manifest distinct characteristics, falling into the bulk incompressible and rigid lattice limits, respectively.

See the article in PRA here: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.053301
See the pre-print here: Excitations of a two-dimensional supersolid https://arxiv.org/abs/2407.01072.

Optical Manipulation of Spin States in Ultracold Magnetic Atoms

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ImageWe present an all-optical method for deterministically controlling the spin composition of a quantum gas, based on a clock-like transition, and demonstrate that this transition can also be used to create spin-selective light shifts! 

The article has now been published in Physical Review Research, and the pre-print can be accessed here: arxiv.org/abs/2405.01499.

Pinning dynamics of vortices in a dipolar supersolid

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ImageNow published in the journal “Few-Body Systems”! Together with collaborators at Laboratori Nazionali del Gran Sasso, we investigate the pinning dynamics of vortices in rotating dipolar supersolids. This work is a follow-up our paper last year on how glitches in the supersolid serve as a versatile analogue of the same behaviour in neutron stars.

See the paper here: Few Body Systems, arxiv.org/abs/2407.03212

Optical Tweezer Arrays of Erbium Atoms

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The T-REQS Lab presents the first successful trapping of single erbium atoms in an array of optical tweezers, marking a significant milestone in the use of erbium for quantum simulation. For the experimental details of this achievement by the T-REQS team, see the following excerpt from the abstract:

Using a single narrow-line optical transition, we achieve deep cooling for direct tweezer loading, pairwise ejection, and continous imaging without additional recoil suppression techniques. Our tweezer wavelength choice enables us to reach the magic trapping condition by tuning the ellipticity of the trapping light. Additionally, we implement an ultrafast high-fidelity fluorescence imaging scheme using a broad transition, allowing time-resolved study of the tweezer population dynamics from many to single atoms during light-assisted collisions. In particular, we extract a pair-ejection rate that qualitatively agrees with the semiclassical predictions by the Gallagher-Pritchard model.

See the pre-print here: Optical Tweezer Arrays of Erbium Atoms arxiv.org/abs/2405.01499.

Der Suprafestkörper: a popular science article on the dipolar supersolid!

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imageIf you have been searching for a high-level overview of the dipolar supersolid phase, look no further than this open access article by Prof. Francesca Ferlaino and Dr. Manfred Mark! Newly published in the journal “Physik in unserer Zeit”, this German language primer lays out the historical background, newly discovered properties and open questions which remain about this paradoxical quantum phase. See the full article below:

Ferlaino, F. and Mark, M.J. (2024), Der Suprafestkörper. Phys. Unserer Zeit. https://doi.org/10.1002/piuz.202301692

A Thouless pump with dipolar interactions

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Thouless pumping represents a powerful concept to probe quantized topological invariants in quantum systems. We explore this mechanism in a generalized Rice-Mele Fermi-Hubbard model characterized by the presence of competing onsite and intersite interactions. While large on-site repulsion leads to a breakdown of quantized pumping , sufficiently large intersite interactions allow for an interaction-induced recovery of Thouless pumps. The stable topological transport at large interactions is connected to the presence of a spontaneous bond-order-wave in the ground-state phase diagram of the model. We also discuss a concrete experimental setup based on ultracold magnetic atoms in an optical lattice.

The article can be found here: Quantum, the pre-print can be accessed here: arXiv

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