Plenary abstracts

On-chip hybrid magnonic systems for quantum information science

Yi Li
Argonne National Laboratory

Recently, hybrid dynamic systems based on magnetic materials have attracted increasing interests as a new branch in quantum information science. Magnetic excitations, or magnons, are collective excitation of magnetic moments with frequency in the range of GHz to THz. Due to diverse coupling mechanisms, magnons can be coupled to a wide variety of excitations such as microwave, optic light, phonons and spins. They are promising for coherent information transfer between distinct physical platforms, making them promising for exploring potentials in quantum sensing and quantum transduction.
In this talk, we develop a superconducting circuit platform for implementing on-chip hybrid magnonic system, where the magnon mode is strongly coupled to the photon mode. In the first example, we explore the use of permalloy (Ni80Fe20) thin film devices, where permalloy is a classical metallic ferromagnet with well-known magnetic dynamic properties and is easy to grow and integrate into complex devices. In the second example, we incorporate chip-mounted single-crystal YIG spheres, where YIG exhibit the lowest damping in the known magnetic materials. In particular, we demonstrate microwave-mediated distant magnon-magnon interactions by coupling two remote YIG spheres to a superconducting resonator as a coherent data bus. In addition, we demonstrate time-domain magnon interference between the two remotely coupled YIG spheres. Our results provide a realistic platform for constructing hybrid magnonic quantum networks at cryogenic temperatures and that can be scaled-up and incorporated into integrated circuits.

Quantum photonics with rare-earth materials

Elizabeth Goldschmidt

University of Illinois at Urbana-Champaign

Optically active and highly coherent emitters in solids are a promising platform for building practical quantum networks. Rare-earth atoms, in addition to having record long coherence times, have the added benefit that they can be hosted in a wide range of solid-state materials. We can thus target particular materials (and choose particular rare-earth species and isotopes) that enable certain application-specific functionalities. I will present recent results from our lab on studying rare-earth atoms in different host materials and configurations. This includes characterizing new stoichiometric rare-earth crystals with narrow line widths and record high emitter densities, as well as photonic integration of rare-earth doped samples to make on-chip quantum photonic devices.

Pushing the limits of membrane selectivity

Seth Darling
Argonne National Laboratory

Transport of solutes through porous membranes underlies numerous separation processes critical to industries ranging from water treatment to biotechnology to resource recovery. However, a dearth of tunable model systems has limited predictive understanding and, therefore, progress in improvements of selective membrane transport. In this presentation, I will give examples of recent advances in developing such systems for both 1D- and 2D-confined transport.

Transport of a spherical solute through a cylindrical pore has been modeled for decades using well-established hindered transport theory, predicting solutes with a size smaller than the pore to be rejected nonetheless because of convective and diffusive hindrance; this rejection mechanism prevents extremely sharp solute separations by a membrane. While the model has been historically verified, solute transport through near-perfect isoporous membranes may finally overcome this limitation. Here, encouraging solute rejections are achieved using nanofabricated, defect-free silicon nitride isoporous membranes. The membrane is challenged by a recirculated feed to increase the opportunity for interactions between solutes and the pore array. Results show the membrane completely reject solutes with greater size than the pore size while effectively allowing smaller solutes to permeate through. With effectively increasing the number of interactions, we propose that a steeper size-selective rejection curve may be achieved. With this traditional hurdle overcome, there is new promise for unprecedented membrane separations through judicious process design and extremely tight pore-size distributions.

The interlayer galleries in membranes integrating two-dimensional (2D) materials drive separation and selectivity, with specific transport properties determined by the chemical and structural modifications. We report an approach to tuning interlayer spacing in membranes derived from clay materials with molecular cross-linkers to control the gallery height, enhance the membrane stability, and manipulate the chemical and electrostatic environment in the channels. The cross-linked 2D phyllosilicate membranes exhibit ion diffusivities tuned by the length and functionality of the selected cross-linking molecule. The 2D nanochannels in these stabilized membranes enable a systematic study of confined ionic transport.

Design of nanoscale materials

Elena Shevchenko

Argonne National Laboratory

Recent advances in the design and application of nanoscale materials are paving the way for groundbreaking solutions to some of the world’s most pressing challenges, from energy production and storage to environmental sustainability. In my talk, we will explore how we can synthetize functional materials to create more efficient photocatalysts, batteries, catalysts, optically active coatings and sensors. We will discuss different strategies to control over composition and function of nanomaterials. We will show how the properties of nanomaterials can be turned by the synthesis parameters. We will discuss the possibility to enhance the function of nanomaterials via direct synthesis, surface modification and polymer templated synthesis to inspire further research and development that will help us move towards a more sustainable future.