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Chiral Phonons

Chiral phonons are an emerging field of research focusing on the angular momentum carried by circularly polarized lattice vibrations. While physical mechanisms arising from electronic spin and orbital angular momentum are ubiquitous in solid-state physics, the role of phonon angular momentum has long only been seen in serving as a dissipation channel for the electronic system. In recent years however, an increasing number of phenomena based on phonon angular momentum has been described, including phonon Hall, phonon Zeeman, phonon Barnett, and Einstein-de Haas, as well as phonon spin Seebeck effects. The microscopic origins of these effects have often been found to be universal, which indicates that phonon angular momentum is a quantity of interest in its own right and chiral phonons need to be studied in a holistic approach.

In this workshop, we aim to bring together experts from diverse fields working on phenomena arising from phonon chirality and angular momentum. These include light scattering phenomena in chiral materials, phonon topology, transport phenomena, phonomagnetism, chirality-induced spin selectivity, ultrafast dynamics, and achiral-chiral phase transitions. Discussing chiral phonon physics in an overarching setting will promote collaborations within the community and strengthen our research efforts for the fundamental understanding of angular momentum in solids and the utilization of chiral phonons in potential applications.

For videos of the talks and further information, please visit the workshop home page.

Young Research Leaders Group Workshop: Magnetism in van der Waals materials: current challenges and future directions

Van der Waals materials are a fruitful playground for developing new emergent physical phenomena from bulk down to the two-dimensional limit. Regarding spins, magnetism arises in these systems either naturally —i.e., in van der Waals magnets— or by design —that is, engineering proximity or twist effects in van der Waals heterostructures, even if the starting layers are not magnetic per se!—. Some fundamental properties underlying these magnetic layers are the spin-switching and spin-transport mechanisms, the magneto-elastic coupling or the emergence of topological spin textures (e.g., skyrmions) and topological effects (e.g., the anomalous spin Hall effect), just to mention a few. Understanding these basic properties is key to its integration into devices, impacting in areas like spintronics, magnonics, or opto-electronics.

A characteristic fingerprint of this field is multi-disciplinarity since several disciplines are strongly involved, including chemical growth, advanced physical characterization techniques at the nanoscale (magnetic imaging, magneto-transport measurements, optical characterization, mechanical testing, …), and theoretical modeling, among others. This workshop gathers young researchers working in these areas, offering a holistic vision of the field of magnetism in van der Waals materials, discussing its current challenges, and envisioning future directions.

Overall, we aim to realize new synergetic effects not only between van der Waals layers but, even more importantly, between young researchers, thus creating a forum for future collaborations and scientific exchange.

For videos of the talks and further information, please visit the workshop home page.

Quantum Functionalities of Nanomagnets

Although numerous solid-state platforms are being developed for quantum applications significant challenges remain with respect to control and scalability, making the development of new qubit technologies a foundational activity pursued intensely. An under-explored platform – nanomagnets – is rapidly demonstrating unique features that could further invigorate the advancement of quantum technologies. This workshop aims to discuss the quantum aspects of tailored magnetic platforms, whose main advantage lies in the high degree of control in manipulation, preparation, parameter tunability, and all-magnetic device integration. It will also discuss some of the recent demonstrations of quantum operations using magnets, the discovery of materials with direct relevance to quantum technology, and the development of sensors able to detect magnetic signals with quantum sensitivity. The event will present the state-of-the-art and opportunities for synergy between quantum technology and tailored spin structures, which holds exciting promise for the creation and preservation of quantum information by magnetic quantum states.

For videos of the talks and further information, please visit the workshop home page.

Characterization and control of quantum materials with optical vortex beams

The fascinating physics of optical vortices, in particular light carrying orbital angular momentum (OAM), has resulted in a large interest and currently OAM light can be generated with high precision in a wide photon energy range. Consequently, also the interplay between optical vortices and matter has been investigated in a broad range of phases, from atoms and molecules to solids and plasmas. For example, the study of optical transitions in semiconductors nicely showed the increased complexity of the allowed optical transitions and how the OAM is transferred to the system. This workshop aims to take this a step further and explore how optical vortices can be used to characterize and control complex quantum materials. Through this workshop, it is foreseen to form and bring together a community and form an overview of current and future research endeavors.

Given the exploratory character, the scope of the workshop is purposely kept broad and topics can include, but are not limited to, the following:
• interaction of vortex beams with quantum condensates
• interaction/coupling of the Berry phase associated with the optical OAM vortex with the topological Berry phase in condensed matter
• inducing quantum phase transitions with OAM
• measuring and driving hidden order with vortex beams
• generation and characterization of chiral bosonic modes

For videos of the talks and further information, please visit the workshop home page.

Quantum Geometry and Transport of Collective Excitations in (Non-)Magnetic Insulators

Quantum geometric properties of band structures and their signatures in experiments have driven condensed matter research over the past decades. This SPICE workshop will focus on recent theoretical and experimental advances in the topological properties of bands formed by magnetic and hybrid bosonic excitations. While the topology of electron bands is well understood, with unambiguous experimental tools to probe theoretical predictions, their bosonic analogs pose challenges. Although bosonic topological excitations, such as magnon Chern bands, Weyl and Dirac semimetals, and nodal-line semimetals have emerged, the lack of quantized responses and the ambiguity of thermal Hall and Nernst effects prevent their distinct experimental identification. Furthermore, traditional spectroscopic methods for resolving bosonic modes, such as inelastic neutron scattering, lack the contrast to resolve topological boundary states. One possible route to bring the topological excitations under control is to make use of highly tunable platforms, such as magnonic crystals and stacked van der Waals layers. Additionally, the ease of hybridization of magnonic excitations with phonons, photons, and plasmons can provide novel opportunities to directly probe the topological fingerprint.

With this workshop, we aim to provide a forum where experts and students can discuss the latest developments, challenges, and future directions in topological magnetism. Some exciting challenges that we aim to address include:

-Identify direct experimental signatures for topological bosonic excitations

-Explore the impact of many-body interactions on the quantum geometry of the single particle spectrum and transport

-Identify the microscopic origins of thermal Hall conductivity in magnetic and non-magnetic insulators

-Engineer the quantum geometry and topology of collective excitations by non-Hermitian, non-equilibrium, and Floquet control

For videos of the talks and further information, please visit the workshop home page.

Spin textures: Magnetism meets Plasmonics

Spin textures in solids originate from the complex interaction between electrons and atoms. In particular, the collective behavior of electrons is often key to emergent physical properties. For example, the spins of localized as well as itinerant electrons can interact to realize statically (meta-) stable magnetic spin textures, including spin-spirals, vortices, skyrmions, multi-q structures, i.e., magnetic arrangements characterized by multiple wave vectors in their magnetic order parameter.
Alternatively, electrons can be excited collectively by electromagnetic waves such that the electrons oscillate to realize plasmons. Being highly endowed with tunability, the field of plasmonics, has rapidly emulated several interesting spin structures.
In both fields, skyrmions and topological excitations play a crucial role spurred by the idea of robust states of matter for applications including storage and information technology. While there are a lot of similarities between magnetic and electromagnetic spin textures there are also key differences in their physics. For example, each field has its individual challenges to realize tailored spin textures: While a limitation in magnetism is that certain competing interactions are required to realize spin structures, in plasmonics certain field components are prohibited hindering the formation of arbitrary spin structures. External stimuli are interesting for both research fields to manipulate the unique magnetic and electronic properties of the excitations.
This workshop aims to bring together experts from both magnetism and plasmonics to foster the discovery of new spin textures.

For videos of the talks and further information, please visit the workshop home page.

Young Research Leaders Group Workshop: Correlation and Topology in magnetic materials

The mathematical concept of “topology”, developed in the past century, has become the real game changer in condensed matter physics. The particular coupling of the electronic wavefunctions with the spin configuration define the material topology, from which unique electronic properties arise. Skyrmions, anomalous spin Hall effect or topological superconductivity are some examples of the fascinating phenomena and applications that this new concept enables.
Besides the potential technological transfer, topology also paves the way for quantum states, a phenomenal playground for investigating fundamental interactions of correlated electrons under topological protection. On top of these correlated materials, topological superconductivity, essential to the realization of quantum computing, is one of the most “hot research lines”, expected to generate the biggest revolution in the field.
By gathering young researchers from both topology and correlation topics, we aim to get a broad perspective of one of the hottest topics in condensed matter physics. The workshop will count on researchers from both experimental and theoretical fields, aiming to promote collaborations across different perspectives.

For videos of the talks and further information, please visit the workshop home page.

Workshop-School on Quantum Spinoptics

This joint workshop and school aims to bring together students and researchers in the separate fields of solid-state physics and quantum optics, with the goal of fostering an exchange of ideas and knowledge that might spawn a new exciting field of “Quantum Spinoptics.” The common ground for this inter-disciplinary field is the increasingly recognized importance to develop techniques to controllably couple qubits (either atoms or solid-state spins) to interesting quantum “baths” (photons or magnetic materials). Such control is expected to open up diverse scientific and technological opportunities, such as:
- Long-distance coupling and entanglement of qubits through coherent interactions or correlated dissipation
- State protection through correlated dissipation (e.g., subradiance) and associated applications
- Quantum sensing and metrology, and novel probes of condensed matter systems
- Realization of novel classes of out-of-equilibrium dynamics and phases
While these ideas are already starting to be explored separately within solid-state physics and quantum optics, we envision that scientific progress and opportunities will significantly accelerate with the cross-fertilization of ideas. The joint workshop-school format is intended to provide a venue equally devoted to the dissemination of latest research developments, discussion of scientific ideas, and providing a pedagogical background to establish a common “scientific language” for this new field. To that end, the event will feature two extended introductory lectures, featuring scientific and pedagogical leaders within the fields of solid-state physics and quantum optics. We thus especially encourage young scholars to attend and to also contribute in a dedicated poster session.

For videos of the talks and further information, please visit the workshop home page.

Quantum Matter for Quantum Technologies

Quantum materials hold the key to unlocking the next frontier of quantum advancements, and at the forefront of this transformation are innovative Josephson junction concepts designed to harness the inherent properties of these quantum materials. This includes pioneering approaches such as integrating Josephson junctions into 2D materials, exploring the intriguing realm of twisted bilayers, devising semiconductor-based superconducting qubits, understanding novel phenomena in chiral and nodal superconductors, just to name a few. Within this diverse landscape, these developments bring forth a wealth of advanced functionalities, including the ability to fine-tune quantum systems through electric gate control, compatibility with magnetic fields, and the exploration of unconventional Josephson potentials.

In this workshop, our vision is to nurture collaborative synergy among diverse scientific communities that have been somewhat disconnected. This collaborative effort aims to foster innovation and deepen our comprehension of various facets leading to novel qubit concepts based on exotic Josephson potentials, novel properties of Josephson quantum matter and the exploration of topological effects. Additionally, we aspire to delve into recent proposals that revolve around unconventional superconductivity. Our shared goal is to establish a new technological paradigm within the realm of quantum technologies, pushing the boundaries of what is currently achievable with standard superconducting circuits and unlocking the full potential of quantum materials and Josephson junctions.

For videos of the talks and further information, please visit the workshop home page.

Hybrid Correlated States and Dynamics in Quantum Materials

Correlated states of electrons give rise to quantum matter, such as ordered magnets, spin liquids, superconductors, and topological materials. In lower dimensions, correlations assume a still pronounced importance. The exciting phenomena hosted and technological applications promised by these states of matter have further inspired the scientific community to engineer hybrids where different ingredients for correlations are provided by separate materials coupled together. Thus, such low-dimensional hybrid nanostructures have enabled engineering novel states of matter with intriguing physics, often not admitted by any single platform.

The workshop shall bring together experts and young researchers from three different communities: (i) Magnetism and Spintronics, (ii) Superconductivity and Strongly Correlated Electrons, and (iii) Low-dimensional nanostructures. The purview includes coherent and incoherent magnetization dynamics in conjunction with the various spintronics effects that allow its manipulation and detection. A key topic will be the recently discovered nonreciprocal effects in magnets e.g., chiral magnons, as well as superconductors, e.g., the superconducting diode effect.

Recent discoveries regarding two-dimensional materials, multi-orbital superconductivity, Ising superconductors, topological superconductivity and quantum sensors coupled to magnets will also be central to the workshop portfolio. Employing fluctuations of currents (e.g, flow of spin or vortices) to probe the quantum nature of transport will form an exciting topic of discussion across communities. Finally, the case of spin fluctuations mediated superconductivity, that is believed to underlie a wide range of unconventional superconductors can best be discussed with the three communities present at the workshop.

For videos of the talks and further information, please visit the workshop home page.