# EU/ERC Projects

The research done in the Department of Physics and Astronomy also involves participation in the EU’s extremely important research framework program Horizon Europe.

### EU collaborative projects in which the University of Bonn is a partner

**Partner**

Prof. Dr. Simon Stellmer

Physikalisches Institut

Nussallee 12

53115 Bonn

**Abstract**

Lasers are the heart of today’s quantum science and technology. Since their first invention they have been a flourishing research area and in a few decades have found application in an enormous variety of fields, eventually populating many aspects of our everyday life, also outside of the research laboratory. Since the beginning, there has been a natural push towards extending the accessible frequency range of coherent radiation, eventually covering the whole infrared (IR), visible (VIS), and ultraviolet (UV) spectrum. The large energy and momenta of UV photons offers enormous potential for novel applications. However, for the same reason, deep technological challenges remain before they can be used effectively in science and technology. UVQuanT will tackle this challenge by developing the necessary industrial and scientific expertise to realise new-era, cost-effective lasers and laser optics for the UV and DUV region, positioning the EU as the front-runner in this technology. UVQuanT will focus on new ways of increasing the production of coherent radiation in the UV and DUV region, developing and testing lower cost, more rugged and practical solutions, and will test these novel systems in a range of experiments targeting quantum technology applications. Combining the talent and expertise of iindustrial and academic partners, UVQuanT will build strong relationships for establishing a path for next-generation quantum

technologies.

**Koordinator**

Fritz Haber Institute - Max-Planck-Gesellschaft

**Laufzeit **

01.10.2022 - 30.09.2026

**Partner**

Dr. Fabian Hügging

Physikalisches Institut

Wegelerstr. 8

53115 Bonn

**Abstract**

Particle physics attracts a global community of more than 10,000 scientists, and Europe’s leadership, with CERN as its major laboratory, is internationally recognised. Discoveries are technology-driven; more performant accelerators require innovative detectors to unfold their scientific potential, driving available or emerging technologies beyond their limits. The role of industry is rapidly increasing, due to the need for highly specialised equipment and due to the scale of the installations, where thousands or millions of components require industrial-scale infrastructure.

AIDAinnova advances the European detector development infrastructures through fostering an intensified co-innovation with industry. Based on the success of the previous EC-funded initiatives AIDA and AIDA-2020, the project as a novel element fully integrates commercial players, 10 industrial companies and 3 RTOs, together with academic institutions into the consortium, which comprises 46 partners from 15 countries. Knowledge transfer will be catalysed through co-innovative work in common detector projects, and it will strengthen the competence and competitiveness of the industrial partners in other markets.

AIDAinnova provides state-of-the-art upgrades of research infrastructure such as test beam and irradiation facilities, and it covers all key technologies for future detectors, following the guidance by the European Particle Physics Strategy Update. The focus is on strategic developments at intermediate technological readiness levels TRL 2-7, where developments are not yet as specific to one particular experiment as in the engineering phase, and it also includes prospective R&D at TRL 1. Therefore, AIDAinnova will unfold synergies by bringing together the expertise from communities aiming at various future projects and maximise the use of resources. Through the large leverage on matching funds from national sources the project leads to enhanced coherence and coordination at a European level.

**Laufzeit**

01.04.2021 - 31.03.2025

**Partner**

Prof. Dr. Franz Josef Hormes

Physikalisches Institut

Nussallee 12

53115 Bonn

**Abstract**

SOLARIS is the first synchrotron built in Poland, under the auspices of the Jagiellonian University. The EU-funded Sylinda project will boost the research capacity of SOLARIS. The synchrotron radiation facility will thus be able to upgrade its X-ray absorption spectrometer. This could result in more effective collaborations with industrial partners in the pharmaceutical, biology, chemical and cosmetics sectors. The staff will be reinforced with an industrial liaison officer, a beamline scientist and a grant officer. Special focus will be placed on improving project management, proposal preparation and administration skills. Furthermore, the project will organise a summer school on science management for early-stage researchers. Their active participation in industrial research projects will broaden their views regarding industry innovation and funding opportunities.

**Koordinator**

Uniwersytet Jagiellonski

**Laufzeit**

01.01.2021 - 31.12.2023

**Partner**

Prof. Dr. Hartmut Schmieden

Physikalisches Institut

Nussallee 12

53115 Bonn

**Abstract**

In particle physics, a fundamental mechanism called strong interaction is responsible for strong nuclear force. This is the base of the Standard Model theory. Researchers are seeking to better understand and explain basic topics in this extremely promising field. They do this by conducting experimental and theoretical studies, mainly through particle collisions at low and high energies and calculations. Developments in state-of-the-art detectors are among their goals. The EU-funded STRONG-2020 project supports a close collaboration in a consortium involving 44 groups, 14 EU Member States, CERN and other institutions from numerous countries. It will create new possibilities, both in science and in applied research, for advanced medical and technological applications.

**Koordinator**

Centre National De La Recherche Scientifique CNRS

**Laufzeit**

01.06.2019 - 31.05.2023

## ERC Grants

The **European Research Council (ERC)** funds outstanding pioneering research based on the scientific excellence of the applicants and the innovative project idea. Numerous researchers at the University of Bonn have been successful since the ERC was launched in 2007. The ERC Grants of the Physics/Astronomy Department can be found on this page.

### ERC Starting Grants

The ERC Starting Grant supports promising young scientists at the beginning of their scientific career (2 to 7 years after their doctorate).

**Principal Investigator**

JProf. Dr. Daqing Wang

Institut für Angewandte Physik

Wegelerstr. 8

53115 Bonn

**Duration**

01.10.2023 - 30.09.2028

**Principal Investigator**

Dr. Guglielmo Lockhart

Physikalisches Institut

Nußallee 12

53115 Bonn

**Abstract**

Quantum field theory (QFT) is the formalism that underlies modern particle and condensed matter

physics. Standard perturbative methods in QFT have been extraordinarily successful in explaining

physical phenomena involving weakly-interacting quantum fields. On the other hand many fundamental phenomena, including phase transitions and nuclear interactions, are described by strongly coupled QFTs for which perturbative techniques are insufficient and a rigorous, predictive theoretical formulation is lacking. Heuristic arguments indicate that a full non-perturbative formulation of QFT must include extended degrees of freedom (a prototypical example being the flux tubes that bind quarks inside the nucleus). My proposal describes a novel approach for studying extended objects in a wide range of QFTs, based on two recent conceptual breakthroughs: first, my research on a special class of theories (the six-dimensional SCFTs) has brought to light a rich algebraic structure that captures the properties of its stringlike excitations; and second, new developments in mathematics and physics point to the existence of a vast generalization of this structure, which is perfectly suited to describe the extended objects of a much wider range of QFTs. This program is organized along three directions: analyze the families of QFTs that can be studied by string-theoretic and geometric methods, and gradually uncover the algebraic structures that describe their extended degrees of freedom; exploit these algebraic structures to obtain novel principles that govern the dynamics of stronglyinteracting QFTs; and determine the new mathematical structures that arise from the combination of the geometric and algebraic description of the extended objects. An ERC starting grant will allow me to undertake this ambitious project whose pursuit will lead to a much deeper understanding of extended degrees of freedom, or their role in QFT, and of the mathematical structures that describe them.

**Duration**

01.09.2023 - 31.08.2028

**Principal Investigator**

Dr. Julian Schmitt

Institut für Angewandte Physik

Wegelerstr. 8

53115 Bonn

**Abstract**

Topology is a powerful paradigm for the classification of phases of matter. One of its direct manifestations in the widely studied Hermitian systems, which are isolated from the environment, are robust states that emerge at the interfaces between matter with distinct topological order. Real systems, however, are never truly isolated from their surroundings and the influence of the environment on the topologically protected states remains to a large extent unknown. Even more importantly, understanding and controlling the openness of non-Hermitian

systems can provide fundamentally new ways to create novel topological states of matter.

TopoGrand will realise a new experimental platform to synthesise non-Hermitian topological materials. It will employ a room-temperature photonic platform combining nanostructured optical microcavities with a molecular medium, to achieve non-Hermitian topological lattices of photon condensates. The system will feature tuneable openness that is unique among other presently available experimental platforms: a controlled flux of excitations via spatially selective pumping and loss, energy dissipation at variable rates, and coherence

modified by grand canonical reservoirs.

New physics will be accessed in the course of this work: TopoGrand will demonstrate genuine non-Hermitian topological phases and edge states without a Hermitian counterpart. Specifically, we will test the emergence of interface states at a topological phase boundary and their robustness against lattice disorder, as well as reservoir-induced fluctuations.

The project presents a completely new approach to topology, which will allow us to create reconfigurable photonic materials with topological protection simply by controlling the environment. With the novel toolbox, I will explore the emerging links between photonics, condensed matter systems and quantum computing, and emulate finite-temperature topological systems, which are at the forefront of research in quantum physics.

**Duration**

01.01.2023 - 31.12.2027

**Principal Investigator**

Prof. Dr. Simon Stellmer

Physikalisches Institut

Nussallee 12

53115 Bonn

**Abstract**

The Standard Model of particle physics (SM), while largely successful, fails to accurately describe the state of the Universe, e.g. with respect to the evident matter/antimatter asymmetry. Various theories seek to conciliate the SM with observations by extending it, and most of these extensions introduce a massive violation of the combined charge invariance and parity (CP) symmetry. The CP violation would reflect in a sizeable permanent electric dipole moment (EDM) of fundamental particles, large enough to be detected by realistic future experiments. A few pioneering experiments already set out to measure the EDM of neutrons, electrons, or atoms. The most stringent upper limit to any EDM is currently obtained by an experiment based on room-temperature gases of mercury. I propose to take this approach to the quantum world by employing ultracold or even quantum-degenerate mercury samples. To this end, we will construct a dedicated quantum gas experiment. We will develop advanced cooling methods, obtain the world’s first Bose-Einstein condensate and degenerate Fermi gas of mercury, and introduce vacuum ultraviolet (VUV) lasers to the field. These ground-breaking innovations will increase the coherence time of the sample, enable a higher detection efficiency, and exploit coherent effects, thereby increasing the sensitivity tremendously. Our measurements of the Hg-199 atomic EDM will complement cold-molecule measurements of the electron's EDM. Technologies developed here can readily be utilized to improve the performance of Hg lattice clocks and will inspire quantum simulations of unique many-body systems. The principal investigator of this project is highly respected for his pioneering work on degenerate quantum gases of strontium. His current work on a nuclear optical clock introduced him to VUV optics and strengthened his footing in the community. Bringing together his expertise in these two fields – quantum gases and VUV optics – will lead the project to success.

**Duration**

01.04.2018 - 31.03.2025

**Principal Investigator**

Prof. Dr. Michael Köhl

Physikalisches Institut

Nussallee 12

53115 Bonn

**Abstract**

We propose to investigate hybrid quantum systems composed of ultracold atoms and ions. The mutual interaction of the cold neutral atoms and the trapped ion offers a wealth of interesting new physical problems. They span from ultracold quantum chemistry over new concepts for quantum information processing to genuine quantum many-body physics. We plan to explore aspects of quantum chemistry with ultracold atoms and ions to obtain a full understanding of the interactions in this hybrid system. We will investigate the regime of low energy collisions and search for Feshbach resonances to tune the interaction strength between atoms and ions. Moreover, we will study collective effects in chemical reactions between a Bose-Einstein condensate and a single ion. Taking advantage of the extraordinary properties of the atom-ion mixture quantum information processing with hybrid systems will be performed. In particular, we plan to realize sympathetic ground state cooling of the ion with a Bose-Einstein condensate. When the ion is immersed into the ultracold neutral atom environment the nature of the decoherence will be tailored by tuning properties of the environment: A dissipative quantum phase transition is predicted when the ion is coupled to a one-dimensional Bose gas. Moreover, we plan to realize a scalable hybrid quantum processor composed of a single ion and an array of neutral atoms in an optical lattice. The third direction we will pursue is related to impurity effects in quantum many-body physics. We plan to study transport through a single impurity or atomic quantum dot with the goal of realizing a single atom transistor. A single atom transistor transfers the quantum state of the impurity coherently to a macroscopic neutral atom current. Finally, we plan to observe Anderson s orthogonality catastrophe in which the presence of a single impurity in a quantum gas orthogonalizes the quantum many-body function of a quantum state with respect to the unperturbed one.

### ERC Consolidator Grant

The *ERC Consolidator Grants* are awarded to promising young scientists who have already proven that they can conduct independent research (7-12 years after their doctorate).

**Principal Investigator**

Prof. Dr. Claude Duhr

Physikalisches Institut

Nußallee 12

53115 Bonn

**Abstract**

The interactions between the elementary particles are encoded into a set of mathematical quantities called scattering amplitudes. Consequently, they are key to making predictions for physical observables that match the precision achieved by current and future high-energy experiments. Computing loop quantum corrections to scattering amplitudes is still a major challenge today, and calls for innovative and groundbreaking new techniques.

Over the last decade, a new field of research that studies scattering amplitudes through the lens of a certain branch of modern mathematics, the so-called theory of motives, has led to breakthroughs in the way we compute loop corrections to scattering amplitudes. This proposal will bring the connection

between scattering amplitudes and modern mathematics to the next level. LoCoMotive will investigate in detail what the theory of motives teaches us about the structure of scattering amplitudes. Its final aim is to achieve a global change of perspective on the mathematical underpinnings of the laws of nature and develop novel computational techniques for scattering amplitudes that are currently beyond reach of conventional state-of-the-art technology.

The ultimate goal of LoCoMotive is threefold: Inspired by cutting-edge research in seeminglydisconnected areas in mathematics and physics, LoCoMotive will

- reveal the mathematics underlying the description of the laws of nature.
- perform the computations needed to uncover and test dualities relating certain gauge and gravity theories.
- play a decisive role in providing the theoretical predictions at the percent level needed for the LHC and future collider experiments.

To sum up, LoCoMotive has a unique multi-disciplinary character. Its results will transcend the traditional boundaries between mathematics and physics, with a major impact on formal aspects of quantum field theory and predictions for the LHC experiments, and possibly even pure mathematics.

**Duration**

01.01.2023 - 31.12.2027

**Principal Investigator**

Prof. Dr. Sebastian Hofferberth

Institut für Angewandte Physik

Wegeler Str. 8

53115 Bonn

**Abstract**

Optical photons, for all practical purposes, do not interact. This fundamental property of light forms the basis of modern optics and enables a multitude of technical applications in our every-day life, such as all-optical communication and microscopy. On the other hand, an engineered interaction between individual photons would allow the creation and control of light photon by photon, providing fundamental insights into the quantum nature of light and allowing us to harness non-classical states of light as resource for future technology. Mapping the strong interaction between Rydberg atoms onto individual photons has emerged as a highly promising approach towards this ambitious goal. In this project, we will advance and significantly broaden the research field of Rydberg quantum optics to develop new tools for realizing strongly correlated quantum many-body states of photons. Building on our successful work over recent years, we will greatly expand our control over Rydberg slow-light polaritons to implement mesoscopic systems of strongly interacting photons in an ultracold ytterbium gas. In parallel, we will explore a new approach to strong light-matter coupling, utilizing Rydberg superatoms made out of thousands of individual atoms, strongly coupled to a propagating light mode. This free-space QED system enables strong coupling between single photons and single artificial atoms in the optical domain without any confining structures for the light. Finally, we will experimentally realize a novel quantum hybrid system exploiting the strong electric coupling between single Rydberg atoms and piezo-electric micro-mechanical oscillators. Building on this unique coupling scheme, we will explore Rydberg-mediated cooling of a mechanical system and dissipative preparation of non-classical phonon states. The three complementary parts ultimately unite into a powerful Rydberg quantum optics toolbox which will provide unprecedented control over single photons and single phonons.

**Duration**

01.05.2018 - 31.10.2023

**Principal Investigator**

Prof. Dr. Frank Bigiel

Argelander Institut für Astronomie

Auf dem Hügel 71

53121 Bonn

**Abstract**

A thorough understanding of the processes regulating the conversion of gas into stars is key to understand structure formation in the universe and the evolution of galaxies through cosmic time. Despite significant progress over the past years, the properties of the actual dense, star forming gas across normal disk galaxies remain largely unknown. This will be changed with EMPIRE, a comprehensive 500hr large program led by the PI at the IRAM 30m mm-wave telescope. EMPIRE will provide for the first time extended maps of a suite of dense gas tracers (e.g., HCN, HCO+, HNC) for a sample of nearby, star-forming, disk galaxies. By means of detailed analysis, including radiative transfer and chemical modelling, we will constrain a variety of physical quantities (in particular gas densities). We will relate these directly to the local star formation efficiency and to a variety of other dynamical, stellar and local ISM properties from existing pan-chromatic mapping of these galaxies (HI, IR, CO, UV, optical) to answer the question: "how is star formation regulated across galaxy disks?". By determining true abundance variations, we will contribute key constraints to the nascent field of galaxy-scale astrochemistry. Detailed comparisons to data for star forming regions in the Milky Way will link core, cloud and galactic scales towards a coherent view of dense gas and star formation. These results will provide an essential anchor point to Milky Way and high redshift observations alike.

**Duration**

01.07.2017 - 31.12.2022

**Principal Investigator**

Prof. Dr. Corinna Kollath

HISKP

Nussallee 14-16

53115 Bonn

**Abstract**

One of our dreams for the future is to control and manipulate complex materials and devices at will. This progress would revolutionize technology and influence many aspects of our everyday life. A promising direction is the control of material properties by electromagnetic radiation leading to photo-induced phase transitions. An example of such a transition is the reported dynamically induced superconductivity via a laser pulse. Whereas the theoretical description of the coupling of fermions to bosonic modes in equilibrium has seen enormous progress and explains highly non-trivial phenomena as the phonon-induced superconductivity, driven systems pose many puzzles. In addition to the inherent time-dependence of the external driving field, a multitude of possible excitation and relaxation mechanisms challenge the theoretical understanding. Recently in the field of quantum optics, a much cleaner realization of a photo-induced phase transition, the Dicke transition, has been observed for bosonic quantum gases loaded in an optical cavity. Above a critical pump strength of an external laser field, the ensemble undergoes a transition to an ordered phase.

We aim to advance the general theoretical understanding of photo-induced phase transitions both in the field of solid state physics and quantum optics. In particular, we will focus on the design and investigation of photo-induced transitions to unconventional superconductivity and non-trivial topological phases. Our insights will be applied to fermonic quantum gases in optical cavities and solid state materials. In order to treat these systems efficiently, we will develop new variants of the numerical density matrix renormalization group (or also called matrix product state) methods and combine these with analytical approaches.

**Duration**

01.09.2015 - 31.08.2022

**Principal Investigator**

Prof. Michael Köhl

Physikalisches Institut

Nussallee 12

53115 Bonn

**Abstract**

We explore unconventional ways how ultracold fermions pair and form collective quantum phases exhibiting long-range order, such as superfluidity and magnetically order. Specifically, we plan to realize and study pairing with orbital angular momentum and pairing induced by long-range interaction. Besides the fundamental interest in unravelling unconventional pairing mechanisms and the interplay between superfluidity and quantum magnetism, our project will also lead to gaining experimental control over topologically protected quantum states. This will pave the way for future topological quantum computers, which are particularly robust to environmental decoherence.

Our project addresses three different aspects: (1) We plan to realize p-wave superfluids in two dimensions. This quantum phase exhibits topological excitations (vortices) with anyonic statistics and an isomorphism to the fractional quantum-Hall effect. We will investigate the unusual properties of p-wave superfluids, such as Majorana fermions, i.e. quasiparticles being their own anti-particles, which are predicted to be localized at vortices. This will boost the long-standing efforts in the cold atoms and condensed matter communities to understand topological states of matter. (2) We aim to realize d-wave pairing in optical lattices using a novel experimental approach. d-wave pairing is closely related to high-Tc superconductivity in the cuprates and we are interested in exploring its interplay with magnetic order. Superfluidity and magnetic order are antagonistic phenomena from a conventional BCS-theory point-of-view and hence several fundamental questions will be answered. (3) We plan to induce long-range interactions using a high-finesse optical cavity leading to a light-induced pairing mechanism. We will search for Cooper pairing in spin-polarized Fermi gases mediated by the interaction of Fermions with a quantized light field. This provides access to a new class of combined light-matter quantum states.

**Duration**

01.10.2014 - 30.09.2019

### ERC Advanced Grant

Successful *ERC Advanced Grantees* are outstanding scientists who have already demonstrated significant research achievements.

**Principal Investigator**

Prof. Dr. Dr. h.c. Ulf-G. Meißner

Helmholtz-Institut für Strahlen- und Kernphysik

Nussallee 14-16

53115 Bonn

**Abstract**

The least understood part of the so successful Standard Model of the strong and electroweak forces is the formation of strongly interacting composites, like hadrons, atomic nuclei and hypernuclei. In addition, the nucleosynthesis in the Big Bang and in stars is fine-tuned at various places, which immediately leads to the question how much these fine-tunings can be offset to still lead to an habitable universe?

Over the last decade, the PI and his collaborators have further improved the chiral effective field theory for two- and three-nucleon forces, have pioneered and refined the extension of this approach to baryon-baryon interactions and, most importantly, have developed nuclear lattice effective field theory, which enabled them to solve longstanding problems in nuclear physics, like the ab initio calculation of the Hoyle state in 12C. Based on these achievements, EXOTIC will provide answers to: i) where are the limits of nuclear stability? ii) what hypernuclei can exist, what are their properties and how is the equation of state of neutron matter modified by the presence of strange quarks? and iii) what limits on the fundamental parameters of the Standard Model are set by the fine-tunings in nucleosynthesis in the Big Bang and in stars?

Apart from answering these big science questions, EXOTIC will, as a by-product, develop methods in effective field theories and Monte Carlo simulations that will be of use in other fields, such as cold atom and condensed matter physics.

**Duration**

01.11.2021 - 31.10.2026

**Principal Investigator**

Prof. Dr. Martin Weitz

Institut für Angewandte Physik

Wegelerstr. 8

53115 Bonn

**Abstract**

Bose-Einstein condensation, the macroscopic ground state occupation of a system of bosonic particles below a critical temperature, has in the last two decades been observed in cold atomic gases and in solid-state physics quasiparticles. The perhaps most widely known example of a bosonic gas, photons in blackbody radiation, however exhibits no Bose-Einstein condensation, because the particle number is not conserved and at low temperatures the photons disappear in the system’s walls instead of massively occupying the cavity ground mode. This is not the case in a small optical cavity, with a low-frequency cutoff imprinting a spectrum of photon energies restricted to well above the thermal energy. Using a microscopic cavity filled with dye solution at room temperature, my group has recently observed the first Bose-Einstein condensate of photons.

Building upon this work, the grant applicant here proposes to study the physics of interacting photon Bose-Einstein condensates in variable potentials. We will study the flow of the light condensate around external perturbations, and exploit signatures for superfluidity of the twodimensional photon gas. Moreover, the condensate will be loaded into variable potentials induced by optical index changes, forming a periodic array of nanocavities. We plan to investigate the Mott insulating regime, and study thermal equilibrium population of more complex entangled manybody states for the photon gas. Other than in an ultracold atomic gas system, loading and cooling can proceed throughout the lattice manipulation time in our system. We expect to be able to directly condense into a macroscopic occupation of highly entangled quantum states. This is an issue not achievable in present atomic physics Bose-Einstein condensation experiments. In the course of the project, quantum manybody states, when constituting the system ground state, will be macroscopically populated in a thermal equilibrium process.

**Principal Investigator**

Prof. Dr. Dieter Meschede

Institut für Angewandte Physik

Wegelerstr. 8

53115 Bonn

**Abstract**

We propose to build a two-dimensional (2D) discrete quantum simulator based on ensembles of ultracold neutral atoms. In this system all degrees of freedom will be controlled at the quantum limit: the number and positions of the atoms as well as their internal (qubit) and vibrational states. The dynamics is implemented by discrete steps of spin-dependent transport combined with controlled cold collisions of the atoms.

Although numerous theoretical studies have considered this architecture as the most promising route to quantum simulation, it has not yet been realized experimentally in all essential aspects.

This simulator allows us to study dynamical properties of single-particle and many-body systems in engineered 2D environments. In single-particle discrete systems, also known as quantum walks, we plan to investigate transport properties connected to graphene-like Dirac points, and localization phenomena associated with disorder. In the many-particle setting we will realize 2D cluster states as needed for measurement-based quantum computation, as well as simple quantum cellular automata.

### ERC Synergy Grants

The *ERC Synergy Grants* support teams of two to four excellent researchers. These can be both young scientists and established researchers.

**Principal Investigator**

Prof. Dr. Sebastian Hofferberth

Institut für Angewandte Physik

Wegelerstraße 8

53115 Bonn

**Abstract**

The past decade has seen remarkable advances in the field of quantum non-linear optics, where individual photons are made to strongly interact which each other. Such strong photon-photon interactions are of both fundamental and technological interest: They are the prerequisite for implementing deterministic quantum logic gate operations for processing optical quantum information. Moreover, photons that strongly interact via a quantum nonlinear medium exhibit complex out-of-equilibrium quantum dynamics that enable one to tailor and control the photon statistics of light. Quantum non-linear effects have been successfully demonstrated with few photons in a number of experimental platforms, which exploit resonant enhancement of emitter-photon coupling via high-finesse optical cavities, collective response of ensembles of strongly interacting Rydberg atoms, so-called superatoms, or efficient coupling of single quantum emitters to guided light in the realm of waveguide quantum electrodynamics (QED). However, it remains a formidable challenge to reach the true

many-body regime of quantum non-linear optics, where strong interactions and entanglement between many photons and many quantum emitters give rise to exotic quantum phases of light, such as photonic molecules or fermionic subradiant states. The objective of SuperWave is to realize this regime by synergizing superatoms and waveguide QED. By uniting the expertise and experimental methods of three teams that have previously driven these fields independently, we will develop near-ideal fiber-coupled nonlinear quantum devices. Their implementation will mark a major breakthrough in quantum optics and constitute a key resource in quantum sensing, quantum metrology, quantum communication, as well as quantum simulations. We will illustrate this

great potential through a number of hallmark experiments such as the coherent fragmentation of a classical light pulse into its highly nonclassical photon number components.

**Duration**

01.11.2023 - 31.10.2029

### ERC Proof of Concept

*Proof of Concept* is a complementary grant to the ERC research grants. It is aimed exclusively at scientists who already hold an ERC grant and wish to pre-commercially exploit a research result from their ongoing or completed project. This is the first step towards technology transfer.

**Principal Investigator**

Prof. Dr. Simon Stellmer

Physikalisches Institut

Nussallee 12

53115 Bonn

**Abstract**

Rotation sensors, also called gyroscopes, are ubiquitous in consumer electronics, navigation, and environmental sensing. The most advanced gyroscopes are ring lasers that are based on the Sagnac effect.

All current compact and transportable devices, however, show significant drift and limited sensitivity, which precludes their usage in fields of application where extremely small rotation rates in the nrad/s to prad/s range need to be measured. These limitations are of purely technical origin: they derive from residual movement of the gaseous laser medium, light scattering, and acoustic fiber noise.

Within the scope of an ERC Starting Grant, we have implemented a disruptively different design of a ring laser gyroscope that circumvents these limitations, now allowing for a compact and transportable device with near-zero drift and improved sensitivity.

Such a device is in high demand for example in seismology, where it would benefit earth quake and tsunami early warning systems. Sensing of environmental ground motion is imperative in the context of climate change. Monitoring the structural health of bridges and other large-scale constructions is another pressing task, where highly precise acquisition of rotation and distortion will have a massive impact on the early and reliable detection of structural fatigue.

Within GyroRevolution, we will demonstrate the supremacy of our concept and show operation outside of the laboratory. We will develop an IPR strategy and prepare a patent application. A detailed competitor and market analysis will constitute the first step on the pathway of deployment via a spin-out company. We will intensify contacts with companies to prepare for future partnerships. Importantly, we will get involved with potential end-users early-on to adapt our innovative technology to their needs. GyroRevolution marks the first and decisive step in technology transfer from fundamental research to a scalable device with a wide range of applications.

**Duration**

01.07.2023 - 31.12.2024