Jahresübersicht für das Jahr 2023
05 Jan 2023
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Prof. Dr. Nir Bar-Gill, Hebrew University, Jerusalem, Israel | |
The study of open quantum systems, quantum thermodynamics and quantum many-body spin physics in realistic solid-state platforms, has been a long-standing goal in quantum and condensed-matter physics.
In this talk I will address these topics through the platform of nitrogen-vacancy (NV) spins in diamond, in the context of purification (or cooling) of a spin bath as a quantum resource and for enhanced metrology and sensing.
I will first describe our work on characterizing noise using robust techniques for quantum control ([1], in collaboration with Ra’am Uzdin). Suppression of such noise can be related to control and cooling of the spin-bath surrounding the NV, using a single optically pumped NV quantum central spin as a refrigerator [2]. I will then present a general theoretical framework we developed for Hamiltonian engineering in an interacting spin system [3]. This framework is applied to the coupling of the spin ensemble to a spin bath, including both coherent and dissipative dynamics [4]. Using these tools I will present a scheme for efficient purification of the spin bath, surpassing the current state-of-the-art and providing a path toward applications in quantum technologies, such as enhanced MRI sensing.
Finally, if time permits, I will describe our work in using NV-based magnetic microscopy to implement quantum sensing in various modalities. I will present measurements of 2D vdW magnetic materials, and specifically the phase transition of FGT through local imaging of magnetic domains in flakes of varying thicknesses [5], as well as a technique for sensing radical concentrations through the change in the charge state of shallow NVs ([6], in collaboration with Uri Banin).
1. T. Zabelotsky et. al., in preparation.
2. P. Penshin et. al., in preparation.
3. K. I. O. Ben’Attar, D. Farfurnik and N. Bar-Gill, Phys. Rev. Research 2, 013061 (2020).
4. K. I. O. Ben’Attar et. al., in preparation.
5. G. Haim et. al., in preparation.
6. Y. Ninio et. al., ACS Photonics 8, 7, 1917-1921 (2021). | |
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09 Jan 2023
RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16 Uhr c.t., Munich |
| Nicolo Piazzalunga, Uppsala U. | |
I'll introduce the higher-rank Donaldson-Thomas theory for toric Calabi-Yau three-folds, within the setting of equivariant K-theory.
I'll present a factorization conjecture motivated by Physics.
As a byproduct, I'll discuss some novel properties of equivariant volumes, as well as their generalizations to genus-zero Gromov-Witten theory of non-compact toric varieties. | |
| at Zoom | |
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10 Jan 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Dr. Nico Döttling, Helmholzt Center for Information Security (CISPA) in Saarbrücken | |
In the early 1990s cryptography went into a foundational crisis when efficient quantum algorithms were discovered which could break almost all public key encryption schemes known at the time. Since then, an enormous research effort has been invested into basing public key cryptography, and secure computation in general, on problems which are conjectured to be hard even for quantum computers. This research program has been resoundingly successful, leading to unexpected developments, such as the discovery of fully homomorphic encryption schemes. Furthermore, cryptography research has now moved beyond just "post-quantum security”, i.e. security against quantum adversaries, and investigates cryptographic protocols for a (still hypothetical) quantum world, where not just adversaries, but also honest users have access to scalable quantum computers and quantum communication channels. This enables applications such as quantum money, which are impossible using purely classical information. In this talk I will give an overview of the field and some of the (in my opinion) most challenging open problems. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Tim Höhne, TU Dortmund | |
We address the notorious metastability of the standard model (SM) Higgs potential and promote it to a model building task: What are the new ingredients required to stabilize the SM up to the Planck scale without encountering subplanckian Landau poles? Using the SM extended by vector-like fermions, we chart out the corresponding landscape of Higgs vacuum stability. We find that the gauge portal mechanism, triggered by new SM charge carriers, opens up sizeable room for stability in a minimally invasive manner.
We also find models with Yukawa portals into Higgs stability opening up at stronger coupling. Several models allow for vector-like fermions in the TeV-range, which can be searched for at the LHC. For nontrivial flavor structure of Yukawa couplings severe FCNC constraints arise which complement those from stability, and push lower fermion masses up to a few hundred TeV. | |
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11 Jan 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Valentina Santoro, ESS, Lund, Sweden | |
The European Spallation Source, ESS, currently under construction in Lund, will be the world’s most powerful facility for research using neutrons. Supported by 3MEuro Research and Innovation Action within the EU Horizon 2020 program, a design study (HighNESS) is now underway to develop a second neutron source below the spallation target. Compared to the first source, located above the spallation target and designed for high cold and thermal brightness, the new source will provide a higher intensity (the total number of neutrons from the moderator), and a shift to longer wavelengths in the spectral regions of Cold (4-10 ˚A), Very Cold (10-100 ˚A), and Ultra Cold (> 500 ˚A) neutrons. The core of the second source will consist of a large liquid deuterium moderator to deliver a high flux of cold neutrons and to serve secondary VCN and UCN sources, for which different options are under study. The features of this new source will boost several areas of condensed matter research and will also provide unique opportunities in fundamental physics with the neutron antineutron oscillations experiment NNBAR. This experiment will search for the baryon number violating process of n → ¯n oscillation with a sensitivity of three orders of magnitude over the previously attained limit obtained at the Institut Laue-Langevin ILL. As a part of the HighNESS project work is ongoing to deliver the Conceptual Design Report of the experiment.
Concerning the design of the Ultra Cold Neutron and Very cold neutron source for the ESS, a digital workshop has been held from February 2nd to February 4th, 2022 where experts from various laboratories and Universities have gathered to propose and discuss ideas and challenges for the development of these sources. During the course of the workshop, several possibilities have been identified on where to locate the VCN and UCN sources. The UCN source could be placed in close vicinity or at some distance from the primary cold source. Regarding the VCN source, we have identified two possibilities. In the first option, the VCNs are extracted from the main CN source using advanced reflectors. While in the other case we make use of a dedicated VCN converter, for which a material capable of delivering a high flux of VCNs is needed. From the point of view of neutronic performance, two promising materials, which are under study in the HighNESS project, are solid deuterium at about 5 K and deuterated clathrate hydrates at around 2 K. In summary in the the talk, the referent will discuss the HighNESS project, the status of the NNBAR experiment and all
the possibilities for a dedicated UCN and VCN source at the ESS. Slides here... | |
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12 Jan 2023
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Dr. Andreas Mooser, MPI für Kernphysik, Heidelberg | |
The hyperfine structure of hydrogen like ions are a unique probe to access nuclear magnetic moments and nuclear structure. Thus, while eliminating the ignorance of essential links in metrology due to insufficiently known magnetic moment, at the same time these ions provide complementary insight into the inner nucleus. The very recently started ³He experiment exploits these characteristics to provide a new standard for absolute precision magnetometry and determine the nuclear charge and current distribution of ³He.
To this end, a novel four Penning trap experiment was designed and built. Using novel techniques, this system enables non demolition measurements of the nuclear quantum state and allows sympathetic laser cooling of single, spatially separated ions to sub-thermal energies [1].
In the first measurement campaign, ³He was investigated by exciting microwave transitions between the ground state hyperfine states. This enabled us to determine the nuclear g-factor, the electronic g-factor and the zero field ground state hyperfine splitting of ³He with a precision of 5*10 -10, 3*10 -10 and 2*10 -11, respectively [2].
Our measurement constitutes the first direct and most precise determination of the ³He nuclear magnetic moment. The result is of utmost relevance for absolute precision magnetometry, as it allows the use of He NMR probes as an independent new standard with much higher accuracy. In addition, the comparison to advanced theoretical calculations enables us to determine the size of the ³He nucleus with a precision of 2.4*10 -17 m.
In future, we aim at a direct determination of the bare nuclear magnetic moment of ³He to be compared to the bound state result. For this measurement, it is essential to implement new methods and technology such as sympathetic laser cooling and a high precision voltage source based on Josephson junctions [3]. The latest results, status and the future prospect of the experiment will be presented.
References
[1] A Mooser et al., J. Phys.: Conf. Ser. 1138, 012004 (2018)
[2] A. Schneider et al., Nature 606, 878 (2022)
[3] A. Schneider et al., Ann. Phys. 531, 1800485 ( 2019) | |
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16 Jan 2023
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Cloé Girad-Carillo, Institut für Physik | |
Searching for the Neutrinoless double beta decay with the SuperNEMO demonstrator: installation, commissioning and sensitivity study | |
| at Zoom | |
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17 Jan 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Georg von Freymann, TU Kaiserslautern | |
Photonic quantum simulation and sensing
Georg von Freymann1,2
1Physics Department and Research Center OPTIMAS, Rheinland-Pfälzische Technische Universität Kaiserslautern Landau RPTU, 67663 Kaiserslautern, Germany
2Fraunhofer Institute for Industrial Mathematics ITWM, 67663 Kaiserslautern, Germany
Applications of quantum technology are highly sought-after and thus supported by public funding agencies. However, the meaning of application varies depending on who you talk to: In the physics community application often means a useful laboratory implementation, while from an industrial perspective, application means solving a measurement problem in production or even creating a saleable product.
To address the physics perspective, I will discuss 3D µ-printed photonic quantum simulators based on coupled waveguide system, focusing on topological protection and Floquet (time-periodic) driving. Such experimental model systems allow for studying these phenomena under very well controlled conditions. Examples are periodic driving of topologically protected edge modes in the one-dimensional Su-Schrieffer-Heeger-chain leading to depopulation of the edge mode despite topological protection [1], periodic driving of two-dimensional honey-comb-lattices establishes topological protection in an otherwise topologically trivial model system [2], switching of topological protection via excitation with and without orbital angular momentum of light [3], and establishing higher-order topological insulators using p-orbitals of the waveguides [4].
From the industry perspective I discuss recent results for terahertz quantum-sensing with undetected photons [5] allowing to measure terahertz spectral properties with visible light only, enabling both single-shot layer thickness measurements as well as spectroscopy.
[1] Z. Cherpakova, C. Jörg, et al., Limits of topological protection under local periodic driving, Light: Science&Applications 8, 63 (2019).
[2] C. Jörg, et al., Dynamic defects in photonic Floquet topological insulators, New J. Phys. 19, 083003 (2017).
[3] C. Jörg, et al., Artificial gauge field switching using orbital angular momentum modes in optical waveguides, Light: Science&Applications 9, 150 (2020).
[4] J. Schulz, J. Noh, et al., Photonic quadrupole topological insulator using orbital-induced synthetic flux, Nature Communications 13, 6597 (2022)
[5] M. Kutas et al, Terahertz Quantum Sensing, Science Advances 6, eaaz8065 (2020) | |
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Theorie-Palaver
Institut für Physik 14:15 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Carlos Tamarit, JGU Mainz | |
The characteristics of the cosmic microwave background provide circumstantial evidence that the hot radiation-dominated epoch in the early universe was preceded by a period of inflationary expansion. Here, it will be shown how a measurement of the stochastic gravitational wave background can reveal the cosmic history and the physical conditions during inflation, subsequent pre- and reheating, and the beginning of the hot big bang era. This will be exemplified with a particularly well-motivated and predictive minimal extension of the Standard Model which is known to provide a complete model for particle physics -- up to the Planck scale, and for cosmology -- back to inflation. | |
Please note the unusual time (we start 15min later than usual) |
18 Jan 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Anatael Cabrera, Paris, France | |
The neutrino discovery (1956), by Reines & Cowan, paved the technical ground behind the establishment of much of today’s neutrino detection. Large instrumented volumes have been achieved via a key (implicit) principle: the impeccable transparency of detector, almost regardless of detection technique.Much of that technology has yielded historical success, including several discoveries and Nobel prizes, such as that of 2015 for the discovery of the Neutrino Oscillation phenomenon leading to an important modification of the Standard Model of Particle Physics. Despite their remarkable success, much of the transparent-based technology is also known to suffer from some key limitations, even after 70 years of maturity towards perfection. The pending challenge is to be to endow detectors with powerful active background rejection while allowing large volume articulation. Indeed, poor particle identification is a long standing issue. This forces experiments to rely on expensive and cumbersome external shield (active or passive), including major overburden in underground laboratories, as the only mean to mitigate otherwise overwhelming backgrounds.
In this seminar, the referent shall introduce the LiquidO technology — in final stages of demonstration — relying, for the first time, heavily on detection medium opacity. The goal is enable sub-atomic particle event-wise imaging, so event topology may be use for particle ID purposes, even in the low MeV region. The development is led by the homonymous LiquidO international academic consortium with institutions over 10 countries. While not perfect, LiquidO appears to be capable to offer several detection features that might lead to breakthrough potential in the context of both neutrino and rare decay physics. The physics potential will be briefly highlighted. Beyond its most basic demonstration, LiquidO remains a testbed context for further detection R&D, where much innovation is expected and ongoing. | |
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19 Jan 2023
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Giuseppe Vallone, University of Padova, Italy | |
Within the last two decades, Quantum Technologies have made tremendous progress, from proof of principle demonstrations to real life applications, such as Quantum Key Distribution (QKD) and Quantum Random Number Generators (QRNGs). Here, we first briefly review the basic principles of QKD and QRNGs. We then discuss the results that we have recently obtained in our group at the University of Padova towards the realization of ultra-fast and secure QRNGs and mature and efficient QKD systems.
Prof. Giuseppe Vallone is an Associate Professor at University of Padua since 2019 (www.dei.unipd.it/~vallone) and co-founder and CTO of ThinkQuantum (www.thinkquantum.com), a spin-off of the Univeristy of Padua pioneering a new generation of secure communication systems based on quantum technology. His research is focused on quantum information, photonic states, quantum communication, quantum random number generators and Orbital Angular Momentum states. He has three patents and more than 130 publications in the area of quantum optics and quantum information. He is currently the coordinator of the European Project QUANGO (www.quango.eu) and the Italian Project QUASAR (quasar.dei.unipd.it). | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 14:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Weixiang Chen, JGU, Chemistry | |
Liquid-liquid phase separation (LLPS) has been identified as a key mechanism regulating the formation of membraneless organelles inside cells. These membraneless organelles, typically composed of DNA, RNA, protein, etc., are involved in many cellular reaction networks by forming micro-sized reactors to locally concentrate specific species or signal molecules, facilitating metabolic reactions, and thus maintaining the functionality of cells. Herein, building on an established model DNA-condensate system, we report an anomalous diffusion process of short oligonucleotide during their uptake by large DNA-condensates driven by specific binding interaction. We show that the interior dynamics of DNA-condensates can be tuned by orders of magnitude at varied salinity, while the diffusional mechanism of signal uptake simultaneously adapts from non-Fickian to Fickian type diffusion. With systematical study on such anomalous diffusion process, we have found pathway to control the velocity of the diffusional process and established a generic mechanism explaining it based on an old polymer physics concept. | |
| at Zoom | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 15:00 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Lorena Baranda, JGU, Chemistry | |
DNA nanotechnology employs synthetic nucleic acid strands to design and engineer nanoscale structural and functional systems of increasing complexity that may find applications in sensing, computing, molecular transport, information processing, and catalysis. Several features make synthetic DNA a particularly appealing and advantageous biomaterial for all the applications mentioned above but more specifically for sensing. First, synthetic DNA sequences, especially if of limited length (<100 nucleotides), have highly predictable interactions and thermodynamics. Second, DNA recently became quite easy and inexpensive to synthesize. Third, DNA contains several functional groups that make it quite straightforward to modify a synthetic nucleotide sequence at both ends or internally. A variety of additional reactive groups can be introduced into DNA sequences. For sensing applications, these functional groups can be used to conjugate signaling moieties (for example, fluorophore/quencher pairs). Importantly, it is also possible to conjugate different recognition elements such as antigens to a synthetic DNA sequence, thus allowing the use of antibodies as targets to be detected with DNA-based sensors. Over my introductory talk, I will present the developed work during my PhD on DNA-based sensors and how I am applying the acquired knowledge in the field of soft colloids and synthetic cells during my postdoctoral research at Prof. Andreas Walther group. | |
| at Zoom | |
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20 Jan 2023
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 10:00 Uhr s.t., Newtonraum, 01-122, Staudingerweg 9 |
| Roland Netz, Freie Universität Berlin | |
TBA | |
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23 Jan 2023
Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Johannes Balz, Institut für Physik | |
Search for invisible Higgs-Boson decays with the ATLAS detector | |
| at Zoom | |
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24 Jan 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Markus Klute, KIT | |
„I think we have it“ – with these words, the then Director General of CERN, Rolf-Dieter Heuer, commented on July 4th, 2012 the detection of a new elementary particle at the Large Hadron Collider (LHC). The search for the Higgs boson, which had lasted almost 50 years, had reached its goal. With the discovery of the Higgs boson, a new era began at the LHC, the precise measurement of the particle's properties. With the help of these properties, conclusions can be drawn about the fundamental structure of the universe and matter. In this colloquium, I will discuss the latest result and prospects in the quest to decipher the Higgs boson. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Quentin Decant, Brussels U. | |
Dark matter (DM) from freeze-in or superWIMP production is well known to imprint non-cold DM signatures on cosmological observables.
It will be discussed how to derive constraints from Lyman-α forest observations for both cases, based on a reinterpretation of the existing Lyman-α limits on thermal warm DM.
Special emphasis is placed on the mixed scenario, where contributions from both freeze-in and superWIMP are similarly important. In this case, the imprint on cosmological observables can deviate significantly from thermal warm DM. The above will be illustrated by studying a coloured t-channel mediator DM model, in which case contributions from both freeze-in through scatterings and decays, as well as superWIMP production can be important. The entire cosmologically viable parameter space, cornered by bounds from Lyman-α observations, the LHC, and Big Bang Nucleosynthesis, will be mapped. | |
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25 Jan 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Peter von Ballmoos, IRAP, Toulouse, France | |
The tentative detection of a few anti-Helium nuclei [1] is presently revitalising the discussion on the existence of baryonic antimatter in the Universe. As ”the discovery of a single anti-helium nucleus in the cosmic ray flux would definitely point toward the existence of stars and even of entire galaxies made of anti-matter” [2] it has been proposed that the anti-Helium nuclei could originate from anti-clouds or anti-stars in the solar vicinity [3]. We discuss possible entities of antimatter in the Universe that would be probed through ordinary matter, with annihilation-radiation providing indirect evidence for their presence [4]. The observations of high energy (∼ 100 MeV) gamma-rays sets limits on the fraction of nuclear antimatter contained in our local and Galactic neighbourhood. We review recent gamma-ray [5] observations that set upper limits on such emissions.
[1] S. Ting, https://indico.cern.ch/event/729900, (2018)
[2] P.Salati, et al., Nuclear Physics B, 70, 1-3, 492, (1999)
[3] V. Poulin, et al., Phs. Rev. D 99, 023016, (2019)
[4] P. von Ballmoos, Hyperfine Interact. 228, 91,, (2014)
[5] S. Dupourque, et al., Phs. Rev. D 103, 083016, (2021) | |
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SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t., None |
| Claus Ropers, MPI for Biophysical Chemistry and University of Göttingen | |
Developments in ultrafast electron microscopy | |
| at Zoom and SPICE YouTube Channel | |
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26 Jan 2023
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Prof. Vahid Sandoghdar, Max-Planck-Institut für die Physik des Lichts, Erlangen | |
Laboratory manipulation of single quantum emitters and single photons has matured to a routine procedure over the past two decades. These activities have led to new emerging topics such as optomechanical functionalities and coherent cooperative interactions among several quantum emitters. In this presentation, I discuss our efforts of the last decade in coupling molecules to high-finesse Fabry-Perot cavities and nanoscopic waveguides on a chip, demonstrating dipole-induced transparency, strong coupling and single-photon nonlinearity. Moreover, I present data on precision spectroscopy of the vibronic transitions in single molecules as well as theoretical conception of hybrid optomechanical platforms for achieving long coherence and storage times. I will also present the latest results on the coupling of two or molecules to each other via a common mode of a micro-resonator. | |
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Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 11:30 Uhr s.t., Hörsaal Kernphysik |
| Andrey Milchev, Institute of Physical Chemistry, Bulgarian Academy of Sciences | |
Translocation Dynamics of Vesicles Through Narrow Pores | |
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Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 14:00 Uhr s.t., 01-122 Newton Raum |
| Vincent Cros, Unité Mixte de Physique CNRS, Thales, Univ. Paris-Saclay | |
From 2D skyrmions to 3D cocoons : nucleation, motion and electrical detection of non collinear topogical spin textures
Vincent Cros
Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767, Palaiseau, France.
In the last decade, magnetic multilayers have proven to be essential structures for creating and investigating complex, topologically non-trivial spin textures through the ability to tune their composition and properties [1-2]. Two-dimensional magnetic textures such as skyrmions (or chiral domain walls) were mostly under focus. First, I will share some of our recent results showing the skyrmion nucleation can be precisely controlled using injection of current pulses through artificial notches and show how the spin-orbit torques, responsible for the skyrmion motion, can be optimized in multilayers. More specifically, I will explain how, in atomically thin Co, the SOTs amplitudes, both for damping and field-like symmetries, varies significantly when a light element, such as Al is deposited on top of Co, surpassing the values existing in literature [3]. Then I will describe how the presence and the displacement of skyrmions can be precisely followed through a simple electrical detection. By relying on our ability to perform fully-electrical manipulation and detection of magnetic skyrmions in multilayers, I will present some recent device developments for performing a basic unconventional computation operation in hardware.
Beyond the 2D skyrmions, a strong interest has emerged for more complex magnetic objects which display a non-homogeneous behavior over the vertical dimension, giving them a 3D character e.g. magnetic bobbers [4] or the recently observed hopfions [5]. In the second part of my talk, I will present our recent results on 3D spin textures, called skyrmionic cocoons [6], that have a typical ellipsoidal shape and that can be stabilized in aperiodic magnetic multilayers with a variable thickness for the ferromagnetic elements. Interestingly, these skyrmionics cocoons can coexist with more standard tubular skyrmions going through all the multilayer as evidenced by the existence of two very different contrasts in room temperature magnetic force microscopy. They can also be electrically detected using magneto-transport measurements, an interesting feature for potential applications. The presence of these novel skyrmionic textures as well as the understanding of their layer resolved chiral and topological properties have been investigated by micromagnetic simulations. Finally, I will describe how the use of x-ray holography and x-ray laminography gives a precise insight into the 3D distribution of the magnetization which demonstrate the 3D nature of skyrmionic cocoons.
Financial supports from FLAG-ERA SographMEM (ANR-15-GRFL-0005), from ANR MEDYNA (ANR-20-CE42-0012), from “Investissements d’Avenir" program SPiCY (ANR-10-LABX-0035), from France 2030 government grant (ANR-22-PEPR-Electronique-EMCOM and ANR-23-PEPR-Spin) and the EU Horizon2020 Programme under FET-Proactive Grant agreement No. 824123 (SKYTOP) are acknowledged.
[1] A. Fert, N. Reyren and V. Cros, Nat. Rev. Materials 2, 17031 (2017)
[2] K. Everschor-Sitte et al, J. Appl. Phys. 124, 240901 (2018)
[3] S. Krishnia, VC et al, arXiv:2205.08486 (2022)
[4] F. Zheng et al. Nat. Nanotech., 13, 451 (2018)
[5] N. Kent et al. Nat. Comm. 12, 1 (2021)
[6] M. Grelier, VC et al. Nature Comm, 13, 6843 (2022) | |
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30 Jan 2023
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 16:00 Uhr s.t., Medien-Raum (03-431) |
| Joo-Von Kim, CNRS, Université Paris-Saclay | |
Resonant dynamics and anomalous thermal diffusion of magnetic skyrmions | |
| at Zoom | |
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RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16 Uhr c.t., None |
| Konstantin Wernli, University of Southern Denmark | |
In the Batalin-Vilkovisky (BV) formalism, one can define a perturbative (i.e. given by Feynman graphs and rules) partition function $Z(x_0)$ for any choice of classical background (solution to Euler-Lagrange (EL) equations) $x_0$. In some examples one can extract from $Z$ a volume form on the smooth part of the moduli space of solutions to EL equations, and compare its integral with non-perturbative approaches to quantization. I will review this construction, some results from examples in the literature and ongoing joint work with P. Mnev about the behaviour at singular points $x_0$. | |
| at Zoom | |
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Seminar about Experimental Particle and Astroparticle Physics (ETAP)
Institut für Physik 12:30 Uhr s.t., Staudingerweg 7, Minkowskiraum |
| Peter Krämer, Institut für Physik | |
Search for short and long-lived axions in H -> a a -> 4 photons decays with the ATLAS experiment at the LHC | |
| at Zoom | |
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Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 16:00 Uhr s.t., Medien-Raum (03-431) |
| Joo-Von Kim, Centre for Nanoscience and Nanotechnology, CNRS, Université Paris-Saclay | |
Magnetic skyrmions are nanoscale, chiral topological solitons which exhibit a wide variety of interesting dynamical phenomena that have solicited much interest for fundamental reasons and technological applications alike. In this talk, I will discuss some recent experimental and theoretical results on two aspects of skyrmion dynamics in ferromagnetic thin film systems. The first involves the resonant dynamics in multilayered films of [Pt/FeCoB/AlOx]20, which are found to host dense robust skyrmion lattices at room temperature with a relatively low Gilbert damping of ∼0.02 [1]. Broadband ferromagnetic resonance measurements, combined with micromagnetic simulations, reveal distinct resonant modes detected in the skyrmion lattice phase. These are found to involve localised excitations, along with skyrmion core precession emitting spin waves into uniform background with wavelengths in the 50–80 nm range. The second aspect involves thermal diffusion of skyrmions in frustrated systems under spin-orbit torques, where the helicity dynamics leads to an anomalous drift that strongly depends on the strength of the Dzyaloshinskii-Moriya interaction. Such drift processes suggest the importance of helicity coupling to spin-orbit torques and may have bearing on dipole-stabilized bubbles for which drive-dependent skyrmion Hall angles and low drift velocities have been reported. [1] T. Srivastava et al, arXiv:2111.11797 [cond-mat.mes-hall]. | |
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31 Jan 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Dr. Philipp Schmidt-Wellenburg, PSI Switzerland | |
An electric dipole moment (EDM) of a fundamental particle would violate time and parity symmetry and by the virtue of the CPT theorem also the combined symmetry of charge conjugation and parity inversion. Searches for EDM are generally considered highly sensitive probes for new physics and might shed light on still unresolved questions in particle physics and cosmology like the origins of matter, dark matter, and dark energy.
At the Paul Scherrer Institute in Switzerland, we are setting up an experiment searching for a muon EDM with a sensitivity of 3E-21 ecm using, for the first time, the frozen-spin technique~\cite{Farley2004PRL} in a compact storage ring. This will lay the ground work for a second phase with a final precision of better than 6e-23 ecm.
This staged approach to search for a non-zero muon EDM probes previously uncharted territory and tests theories of BSM physics by: i) improving the current direct experimental limit of d < 1.5E-19 ecm (CL 90%) by roughly three orders of magnitude;
ii) being a complementary search for an EDM of a bare lepton;
iii) being a unique test of lepton-flavor symmetries;
and iv) in the case of a null result, will be a stringent limit on an otherwise very poorly constrained Wilson coefficient. | |
|
Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Felix Kahlhöfer, KIT | |
Given our detailed knowledge of the dark matter energy density in the present universe, it is of great interest to study its evolution at early times in order to understand the mechanism of dark matter production. A particularly intriguing scenario, known as freeze-in, is that dark matter particles have tiny couplings and never enter into equilibrium with the thermal bath of Standard Model particles. In this talk, I will discuss various technical challenges that arise in this scenario as a result of the high temperatures and densities in the early universe. Specifically, I will show how to consistently treat the spin statistics of relativistic quantum gases and how to accurately calculate dark matter production via the Higgs resonance. Finally, I will discuss the case of freeze-in with low reheating temperature, which may be testable through cosmological, astrophysical and laboratory observations. | |
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01 Feb 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| CANCELED: Prof. Dr. Steen Hannestad, Univ. Aarhus, Denmark | |
Neutrino physics in the era of precision cosmology | |
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02 Feb 2023
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Prof. Stephan Schiller, Heinrich-Heine-Universität Düsseldorf, Institut für Experimentalphysik | |
Molecular hydrogen ions (MHI), the simplest molecules, are three-body quantum systems composed of two simple nuclei and one electron. They are of high interest for fundamental physics and metrology because they provide the missing link between the fields of mass and g-factor measurements with Penning traps and spectroscopy of hydrogen-like atoms.
Basically, the new ingredients introduced by the MHI are the long-range nucleus-nucleus interaction, absent in the hydrogen atom, and the quantized motion of the nuclei.
Precision spectroscopy of the MHI can thus furnish novel results: (1) on the masses of proton and deuteron (in the future, also of tritium), (2) set limits for beyond-Standard-Model (BSM) forces, (3) verify the wave character of matter, and (4) test alternative theories of quantum mechanics. This is performed by comparing or matching experimental and theoretical rotational and/or vibrational frequencies. The comparison is enhanced by the availability of several recently measured transition frequencies and recent advances in ab initio theory.
An additional opportunity for probing the interactions between the particles within the MHI is the precision measurement of its hyperfine structure (HFS). Only the synthesis of the HFS of the hydrogen atom, of the deuterium atom and of the molecular hydrogen ion allows probing the physics of HFS
at the finest level, resolving the issue of the uncalculable nuclear contributions.
We present recent results of our spectroscopy of sympathetically cooled MHI, its results and interpretation. An outlook on near-future studies is also given. | |
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GRK 2516 Soft Matter Seminar
Uni Mainz 14:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Swapnasopan Datta, JGU, Chemistry | |
Conventional chemistry deals with reactants that lead to stable molecules following a classical equilibration pathway. The same holds for classical self-assembly processes, in which non-covalent interactions lead to assembly according to thermal equilibration. There are also a number of systems that reach a metastable state momentarily, and subsequently jump to another lower energy state. In supramolecular systems, this is called pathway complexity. The propensity to transition from a metastable state to an equilibrium state is a function of the energy barrier with respect to thermal energy. This is fundamentally different from the far-from-equilibrium way living systems work, which can be achieved by employing a ‘fuel’ which drives a system to a high energy state and coupling it with an environment which can bring the system back to the original state. Keys to non-equilibrium behaviour are the mechanisms through which systems are able to extract energy from the chemical reactants (‘fuel’) that drive such processes. In our group, a fuel driven enzyme mediated reaction network was established where a ligation reaction occurs followed by a dynamic steady state, whose lifetime depends on the fuel concentration and dynamics is decided by the ratio of the ligation and restriction enzymes, and finally the restriction process dominates giving back the monomers. This is achieved in our case by using ATP as a fuel which activates a ligation enzyme leading to formation of DNA polymers which get cleaved by the restriction enzyme giving back the monomers. By tuning the interactions between these polymers, one can give rise to multivalent DNA coacervates which phase separate as a function of time and eventually vanish when the restriction step dominates. This liquid liquid phase separation (LLPS) process is fundamentally different from conventional coacervation in that it occurs as a result of interaction between polymers which are at a very high energy as opposed to thermodynamically stable phase separation. In this talk I will talk about trapping such a reaction module inside a ‘protocell’ which is a simple mimic of a real cell and explore the possibility of making a synthetic cell bottom up inside which transient LLPS might occur. For this project, we are using liposomes as cell mimics as the phospholipid bilayer which they contain closely resembles a cell. | |
| at Zoom | |
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03 Feb 2023
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 10:00 Uhr s.t., Newtonraum, 01-122, Staudingerweg 9 |
| Jeetain Mittal, Texas A&M | |
TBA | |
|
06 Feb 2023
RIND seminar on Mathematical Physics and String Theory
U. Mainz, LMU Munich, U. Heidelberg, U. Vienna 16 Uhr c.t., Munich, Theresienstr. 37A, R. 348 |
| Renann Lipinski Jusinskas, Prague | |
In this talk I will present a worldsheet model obtained from "twisting" the target space CFT of conventional string theory. The physical spectrum becomes finite and corresponds to the massless spectrum of closed strings plus a single massive level of the open string. The underlying idea is to explore the field/string theory interface in both directions. On one hand, the goal is to generate effective field theories describing massive higher spins using worldsheet methods. Conversely, we may try to use field theory methods to obtain a systematic description of string scattering amplitudes using field theory methods. | |
| at Zoom | |
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07 Feb 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Dr. Tom Aumann, TU Darmstadt & GSI Darmstadt | |
Reactions with short-lived nuclei are key to understand the properties of neutron-rich nuclei and neutron-rich nuclear matter. In recent years, quasi-free scattering experiments have been developed and established for experiments with radioactive beams at GSI and RIKEN. The inverse kinematics of the reaction opens thereby the possibility for a complete characterisation of the final state, which results in an almost background-free measurement. Recent results with stable and radioactive beams will be discussed including the first measurement of short-range correlations in inverse kinematics, the observation of alpha clusters at the surface of heavy nuclei, as well as the observation of a correlated four-neutron state. The perspective for a precise determination of the neutron-neutron scattering length using the 6He(p,p alpha)2n reaction will be discussed as well. | |
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Theorie-Palaver
Institut für Physik 14:00 Uhr s.t., Lorentz room (Staudingerweg 7, 5th floor) |
| Weiguang Jiang, JGU Mainz | |
Nuclear saturation is a key property of low-energy nuclear physics that depends on the fine details of the nuclear interaction. We develop a unified statistical framework that uses realistic nuclear forces to link the theoretical modeling of finite nuclei and infinite nuclear matter. We also construct fast and accurate emulators for nuclear-matter observables and employ an iterative history-matching approach to explore and reduce the enormous parameter domain of Delta-full chiral interactions. | |
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08 Feb 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Julien Lesgourgues, Aachen | |
Cosmologists are puzzled by a tension between the results of two categories of observations, which has been growing over the past few years. This “Hubble tension” arises from contradictory indications concerning the current expansion rate of the universe. The referent will try to give a pedagogical overview of this problem, with a summary of the physical assumptions that go into the interpretation of each observation. Then, assuming that the tension persists with future data releases, he will give examples of the kind of new fundamental physics that could help solving it. Slides here... | |
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09 Feb 2023
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14 Uhr c.t., IPH Lorentzraum 05-127 |
| Prof. Dr. Immanuel Bloch, Max-Planck-Institute of Quantum Physics, Garching | |
Quantum Simulations using Ultracold Atoms in Optical Lattices 40 years ago, Richard Feynman outlined his vision of a quantum simulator for carrying out complex calculations of physical problems. Today, his dream has become a reality and a highly active field of resarch across different platforms ranging from ultracold atoms and ions, to superconducting qubits and photons. In my lecture, I will outline how ultracold atoms in optical lattices started this vibrant and interdisciplinary research field 20 years ago and now allow probing quantum phases in- and out-of-equilibrium with fundamentally new tools and single particle resolution. In addition, I will show how fundamentally new avenues of controlling light-matter interactions can be realized based on the rich interplay of photon-mediated dipole-dipole interactions in structured subwavelength arrays of quantum emitters. In the experiments, we directly observe the cooperative subradiant response of such an ordered array of ultracold atoms. Through spatially resolved spectroscopic measurements, our experiments show that the array acts as an efficient mirror formed by only a single monolayer of a few hundred atoms. Finally, I will discuss latest experiments, where the optical properties of the entire array can be switched via a single Rydberg impurity that is deterministically prepared in the center of the array. This opens the path towards novel structured quantum light matter interfaces with unique properties in free space. | |
|
Seminar über Theorie der kondensierten Materie / TRR146 Seminar
K. Binder/ A. Nikoubashman / F. Schmid / G. Settanni / T. Speck / M. Sulpizi / P. Virnau 15:00 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7, |
| Roberto Covino, Frankfurt Institute for Advanced Studies | |
Molecular self-organization driven by concerted many-body interactions produces the ordered structures that define both inanimate and living matter. Understanding the physical mechanisms that govern the formation of molecular complexes is key to controlling the assembly of nanomachines and new materials.
Molecular dynamics simulations and single-molecule experiments offer the unprecedented possibility to reveal mechanisms of molecular self-organization in high resolution. However, outstanding limitations hinder their success. Machine learning and artificial intelligence promise to empower both approaches to overcome fundamental challenges.
In the first part of my talk, I will present an autonomous AI that learns molecular mechanisms from computer simulations. The AI agent simulates infrequent and stochastic molecular reorganizations and progressively learns how to predict their outcome. Using symbolic regression, we distill simplified quantitative models that reveal mechanistic insight in a human-understandable form. Our innovative AI enables sampling rare events by autonomously driving many parallel simulations with minimal human intervention and aids their mechanistic interpretation. I will present applications on nucleation processes, the assembly of membrane proteins in lipid bilayers, and polymer and protein folding.
In the second part of my talk, I will discuss how integrating physical modeling and AI helps extract mechanistic understanding from single-molecule force spectroscopy. While these experiments offer the possibility of measuring fundamental quantities like free energies, these measurements are often incomplete and indirect. In practice, we measure a few order parameters that are the outcome of the coupled dynamics of the molecule and the mesoscopic experimental apparatus, which could lead to estimation artifacts. I will discuss this problem as Bayesian inference and illustrate how simulation-based inference provides a powerful solution. Coupling a simulator that encodes the physics of the measuring process with density estimation using neural networks leads to accurate estimates of molecular free energies.
In conclusion, integrating physics-based models and AI provides a powerful way to extract accurate quantitative information from simulations and biophysical experiments. | |
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15 Feb 2023
SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t., None |
| Alberta Bonanni, Johannes Kepler University | |
A stride down the quantum materials roadmap | |
| at Zoom and SPICE YouTube Channel | |
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22 Feb 2023
SPICE-Spin+X Seminar
TUK and JGU 15:00 Uhr s.t., None |
| Angela Wittmann, JGU | |
Exploring spintronics at unconventional hybrid interfaces | |
| at Zoom and SPICE YouTube Channel | |
|
16 Mar 2023
Seminar über die Physik der kondensierten Materie (SFB/TRR173 Spin+X und SFB/TR288 Kolloquium, TopDyn-Seminar)
JGU 14:00 Uhr s.t., 01-122 Newton Raum |
| Masahiro Yamashita, Department of Chemistry, Faculty of Science, Tohoku University, Sendai, Japan | |
Spintronics, based on the freedoms of charge and spin of the electron, is a key technology in the 21st century. Magnetic random access memory (MRAM), which uses giant magnetoresistance (GMR), has several advantages compared with electronics. Although conventional magnets composed of transition metals are normally used, in our study, we use molecule-based nano-magnets and single-molecule magnets (SMMs) to overcome “Moore`s Limitation”. SMMs are also available for quantum computer. I will talk about the molecular spin qubits for quantum computer ([1]Crystal Engineering Method, [2]g-Tensor Engineering Method, [3]Orbital Engineering Method, and [4]Molecular Technology Method) as well as high-density memory devices such as single-molecule memory device, SMMs encapsulated into SWCNT, and metallic conducting SMMs with negative magnetoresistances. | |
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zukünftige Termine
18 Apr 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Dr. Masaki Hori, JGU Institute for Physics | |
Metastable antiprotonic helium is an exotic atom composed of a helium nucleus, electron, and an antiproton. It is among the hadron-antihadron systems with the longest known lifetimes. Laser light can be used to excite atomic transitions involving the antiproton orbital. By utilizing sub-Doppler two-photon laser spectroscopy and buffer gas cooling, its atomic transition frequencies were measured to ppb-scale precision. Comparisons with the results of QED calculations allowed the antiproton-to-electron mass ratio to be determined as 1836.1526734(15). The results were used to set upper limits on fifth forces between antiprotons and nucleons at atomic length scales, and on forces that may arise between an electron and antiproton mediated by hypothetical bosons. Efforts are currently underway to improve the experimental precision using CERN’s ELENA facility. We also observed narrow spectral lines of these atoms formed in superfluid helium with a surprisingly high spectral resolution of 2 parts per million. This revealed the hyperfine structure arising from the spin interaction between the antiproton and electron, despite the atom being surrounded by a dense matrix of normal atoms.
Metastable pionic helium (πHe+) contains a negative pion occupying a state of n≈l-1≈17, and retains a 7 ns average lifetime. We recently used the 590 MeV ring cyclotron facility of Paul Scherrer Institute to synthesize the atoms, and irradiated them with infrared laser pulses. This induced a pionic transition within the atom and the π- being absorbed into the helium nucleus. This constitutes the first laser excitation and spectroscopy of an atom containing a meson. By improving the experimental precision, the pion mass may be determined to a high precision as in the antiproton case. | |
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19 Apr 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Sebastian Ellis, Geneva University, Switzerland | |
Gravitational waves | |
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20 Apr 2023
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Dr. Fernando Lemini, ICTP (Intl. Center for Theoretical Physics), Trieste, Italy | |
TBA | |
|
25 Apr 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Dr. Gaute Hagen, Oak Ridge National Lab. Knoxville - USA | |
High performance computing, many-body methods with polynomial scaling, and ideas from effective-field-theory is pushing the frontier of ab-initio computations of nuclei.
Here I report on advances in coupled-cluster computations of nuclei starting from chiral Hamiltonians with two- and three-nucleon forces. The ab-initio approach can now be used to address fundamental questions related to the nature of the neutrino by accurate computations of neutrino-less double beta decay and making first steps towards neutrino-nucleus scattering on relevant nuclei. Global surveys of bulk properties of medium-mass and neutron- rich nuclei from ab-initio approaches are now possible by using reference states that break rotational symmetry. These calculations have revealed systematic trends of charge radii in various isotopic chains, questioned the existence of certain magic shell closures in neutron-rich nuclei, and confrontation with data have exposed challenges for ab- initio theory. By restoring rotational symmetry, we have made predictions for the rotational structure of neutron-rich neon isotopes including 32,34Ne.
In addition to entire regions of the nuclear chart now being targeted by ab-initio computations, entirely new ways to make quantified predictions are becoming possible by the development of accurate emulators of ab-initio calculations. These emulators reduce the computational cost by many orders of magnitude allowing for billions of simulations of nuclei using modest computing resources. This allows us to perform global sensitivity analysis, quantify uncertainties, and use novel statistical tools in predicting properties of nuclei. Recently we used these tools to make a quantified prediction of the neutron skin in 208Pb, and found that the neutron-skin is smaller and more precise than a recent extraction from parity-violating electron scattering but in agreement with other experimental probes. We have also used these tools to address the questions of what drives deformation in atomic nuclei and whether 28O is a bound nucleus. These developments demonstrate how realistic two- and three-nucleon forces act in atomic nuclei and allow us to make quantitative predictions across the nuclear landscape. | |
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26 Apr 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Ryan Mitchell, Indiana University, USA | |
Using the idea of a field guide as a template, the referent will briefly review the rapidly expanding catalog of known mesons, which are strongly interacting subatomic particles made from equal numbers of quarks and antiquarks. While most mesons can be successfully described as one quark bound to one antiquark, recent discoveries point towards the existence of new meson families. These discoveries, made at experiments such as the BESIII e+e- experiment in Beijing and the LHCb pp experiment at the LHC, offer new contexts in which to study the strong force of particle physics. | |
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27 Apr 2023
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Dr. Jack Devlin, Imperial College, London, UK | |
TBA | |
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02 May 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Peter Zoller, University of Innsbruck and IQOQI - Austria | |
The development of atomic quantum simulation platforms has led to the creation of a new generation of programmable quantum simulators that can be scaled to large particle numbers while maintaining a certain degree of programmability.
This talk reports on theory-experiment collaborative work using trapped ion platforms with up to fifty-one qubits/spins, where we develop and demonstrate quantum protocols that can address questions ranging from fundamental to practical.
Examples include first observation of area law vs. volume law entanglement in ground and excited states of many-body systems, and quantum simulators acting as programable quantum sensors implementing near “optimal” entanglement-enhanced quantum metrology. | |
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03 May 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Ida Zadeh, JGU Mainz | |
A conformal field theory is a physical theory which is invariant under changes in its length or energy scale. It describes the physics of boiling of water. In this talk, the referent will present how conformal field theory is used as a powerful tool to study quantum gravity. She will discuss how conformal field theories describe quantum properties of a family of black holes, just as quantum mechanics describes the Hydrogen atom. | |
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04 May 2023
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Artur Widera, TU Kaiserslautern | |
TBA | |
|
GRK 2516 Soft Matter Seminar
Uni Mainz 14:30 Uhr s.t., Minkowski Room, 05-119, Staudingerweg 7 |
| Franziska Lissel, Leibniz Institute of Polymer Research, Dresden | |
TBA | |
| at Zoom | |
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09 May 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Dr. Szymon Pustelny, University of Krakau | |
xxx | |
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10 May 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Giovanni de Lellis, Naples University, Italy | |
SND@LHC is a compact and stand-alone experiment to perform measurements with neutrinos produced at the LHC in a hitherto unexplored pseudo-rapidity region of 7.2 < 𝜂 < 8.4, complementary to all the other experiments at the LHC. The experiment is located 480 m downstream of IP1 in the unused TI18 tunnel. The detector is composed of a hybrid system based on an 800 kg target mass of tungsten plates, interleaved with emulsion and electronic trackers, followed downstream by a calorimeter and a muon system. The configuration allows efficiently distinguishing between all three neutrino flavours, opening a unique opportunity to probe physics of heavy flavour production at the LHC in the region that is not accessible to ATLAS, CMS and LHCb. This region is of particular interest also for future circular colliders and for predictions of very high-energy atmospheric neutrinos. The detector concept is also well suited to searching for Feebly Interacting Particles via signatures of scattering in the detector target. The first phase aims at operating the detector throughout LHC Run 3 to collect a total of 250 fb−1. The experiment has been taking data successfully during the proton physics run of 2022. We show the detector concept, design and performance as well as the first physics results. | |
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16 May 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Rebecca Surman, University of Notre Dame, Indiana USA | |
The groundbreaking discovery of the neutron star merger event GW170817 ushered in a new era of multimessenger astrophysics. One key observation was the optical signal that accompanied GW170817, which provided the first firm proof that neutron star mergers produce heavy elements. Still, it is not known exactly which elements are produced by mergers and in what proportions. Are neutron star mergers the sole astrophysical source of the heaviest elements or do other extreme events contribute? A full understanding of neutron star mergers and their role in galactic chemical evolution requires progress in a number of areas including nuclear physics. Thousands of exotic nuclear species participate in neutron star merger nucleosynthesis, and their properties shape abundance patterns and kilonova signals. Here we discuss how nuclear physics uncertainties influence predictions of nucleosynthesis observables. We then explore the promise of experimental campaigns at rare isotope beam facilities to both reduce these uncertainties and provide insight into astrophysical environments of heavy element production. | |
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17 May 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Vera Gülpers, University of Edinburgh | |
Indirect high-precision searches for possible deviations from Standard Model predictions at low energies are an important tool for finding signatures of new physics. Ab-initio theoretical predictions involving the strong nuclear force at small energies are only possible using Monte Carlo methods in a numerical approach known as Lattice QCD. In recent years lattice calculations of several quantities, such as the pion decay constant, have reached a precision of O(1%), where electromagnetic effects can no longer be neglected. In this talk Vera Gülpers will discuss how electromagnetic effects can be included in lattice calculations and present results of our recent calculation of electromagnetic corrections to leptonic pion and kaon decays. | |
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23 May 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Frank Cichos, University of Leipzig | |
Plasmonics is commonly used to confine electromagnetic waves into subwavelength noble metal structures for photonic applications. As an unwanted side effect, heat is generated locally, which is the foundation of thermoplasmonics. Besides numerous very interdisciplinary applications, such local heat generation provides unique dynamic control over microscopic objects in liquids with non-equilibrium physics. I will give two examples.
First, I discuss experiments on active colloidal particles that are self-propelled by thermoplasmonic effects. Such active particles mimic the motility of living species like bacteria but lack the feedback loops that control their behavior. The optical control of plasmonic heating allows us to implement feedback loops, behavior and even learning for active particles. Using this technique, we can show that perception-reaction delays as omnipresent in living systems can be the origin of a variety of dynamical collective states that even display signatures of criticality.
In a second example, I will briefly report on experiments using plasmonic heat generation to enable the control of liquids and macromolecules. Dynamic temperature fields thereby help us to study elementary processes of peptide aggregation as relevant for neurodegenerative diseases over extremely long periods of time. | |
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24 May 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Mikhail Shaposhnikov, EPF Lausanne, Switzerland | |
The referent will overview the problem of baryon asymmetry of the Universe and the theoretical framework within which the baryogenesis, i.e. the dynamical generation of a matter–antimatter asymmetry, can occur. He will discuss different mechanisms for baryogenesis with special emphasis to those of them that can be experimentally tested. | |
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25 May 2023
Seminar über Quanten-, Atom- und Neutronenphysik (QUANTUM)
Institut für Physik 14:00 Uhr s.t., IPH Lorentzraum 05-127 |
| Prof. Enno Giese, TU Darmstadt | |
TBA | |
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30 May 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Angela Wittmann, JGU Institute for Physics | |
Controlled manipulation of a system allows for systematic investigation of the underlying interactions and phenomena. Simultaneously, tunability also enables the development of novel materials systems and devices customized for specific applications. Here, we will focus on materials systems that conventionally have not been used as active components in spintronic devices. We will explore the impact of strain on the antiferromagnetic domain structure via magneto-elastic coupling1. Furthermore, we will delve into hybrid molecule-magnetic interfaces. Molecules offer a unique way of controlling and varying the structure at the interface making it possible to precisely tune the spin injection and diffusion by molecular design2. In particular, chirality has gained recent interest in the context of the chiral-induced spin selectivity effect3. Here, we will explore signatures of spin filtering at a non-magnetic chiral molecule-metal interface paving the path toward novel hybrid spintronics. | |
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31 May 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Robert Wilson, Colorado State University, USA | |
Forty years ago as an undergraduate contemplating graduate school in high energy physics, the referent declined a research assistantship to work on a neutrino experiment because neutrinos weren’t interesting … they were massless and weakly interacting so produced frustratingly few events to analyze even in massive detectors. How things have changed! The more we learn, the more we realize the importance of the most abundant known matter particle in the universe. In the decades since my naïve snubbing of this intriguing particle we have developed a well-established three-flavor paradigm that may help explain the matter-antimatter asymmetry of the universe. Yet beyond that, a few intriguing measurement “anomalies” hint at the existence of something stranger still, a neutrino that does not interact via any known forces except gravity, a sterile neutrino.
Robert Wilson will give a brief overview of the results that motivated a definitive search for sterile neutrinos with a mass in the 1 eV/c2 range – the Short-Baseline Neutrino program at Fermi National Accelerator Laboratory. He will describe the physics sensitivity and the detectors that will measure the appearance of electron-type neutrinos in a muon-type neutrino beam using massive liquid argon time-projection chambers with an emphasis on the 760-ton far detector developed by the ICARUS collaboration. Operating both in Italy’s Gran Sasso underground laboratory and now at Fermilab, this detector demonstrated the viability of the technology for large-scale experiments such as the international Deep Underground Neutrino Experiment (DUNE). | |
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06 Jun 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Susan Gardner, University of Kentucky - USA | |
xxx | |
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07 Jun 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Alexander Gerbershagen, University of Groningen, Netherlands | |
The presentation covers the aspects of the use the accelerators for the hadron therapy. It includes the summary of the advantages of hadron use for radiation treatment of cancer, the technological solutions used for the beam acceleration, dose delivery and application, and an overview over the types of commercially available systems. Following that, the presentation concludes by describing the newly established the PARticle Therapy REsearch Center (PARTREC) in Groningen. Using the superconducting cyclotron AGOR and being embedded within the University Medical Center Groningen, providing proton beams of up to 190 MeV and ion beams (up to Pb) with energies up to 90 MeV/nucleon for pre-clinical research in medical physics and radiobiology. | |
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13 Jun 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Dr. Frank Stefani, Helmholz-Zentrum Dresden-Rossendorf | |
Magnetic fields of planets, stars and galaxies are generated by the homogeneous dynamo effect, or self-excitation, in moving electrically conducting fluids, such as liquid metals or plasmas. Once generated, magnetic fields can promote cosmic structure formation by destabilizing, via the magnetorotational instability (MRI), rotational flows that would be otherwise hydrodynamically stable. Closely related instabilities, such as the current-driven Tayler instability might be at work in the solar tachocline.
For a long time, these topics had been the subject of purely theoretical and numerical research. This situation changed in 1999 when the threshold of magnetic-field self-excitation was exceeded in the two liquid sodium experiments in Riga and Karlsruhe. Since 2006, the VKS dynamo experiment in Cadarache has successfully reproduced many features of geophysical interest such as reversals and excursions. MRI related experiments were partly successful with the observation of the helical MRI and the azimuthal MRI at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), where first evidence of the current-driven Tayler instability in a liquid metal was obtained, too. In another liquid metal experiment at the Dresden High Magnetic Field laboratory (HLD) the “magic point” of coinciding Alfvén and sound speeds was reached, which is thought to play a key role for the heating of the solar corona.
The lecture gives an overview about previous and future liquid metal experiments on dynamo action and magnetically triggered flow instabilities, with special focus on the precession driven liquid sodium experiment and the large-scale MRI experiment that are under construction in the framework of the DRESDYN project at HZDR.
Particular emphasis is placed on generic questions such as the reversal mechanism of the geodynamo and the possibility of a planetary synchronization of the solar dynamo, on which those experiments might shed some fresh light. | |
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14 Jun 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Seyda Ipek, Carleton University, USA | |
New directions in baryogenesis | |
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20 Jun 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Dr. Simone Pirrotta, Italian Space Agency (ASI) Rome, Italy | |
Small satellites are nowadays extremely powerful, flexible and sustainable platforms that can be used to complement the missions usually assigned to larger spacecrafts. Modularity, standardization, intensive use of state-of-the art COTS technologies consent to prepare cheaper missions in shorter timeframes, thus allowing a more frequent access to space environment, including Cislunar and Interplanetary. The Italian Space Agency – ASI promotes, funds and coordinates the national initiatives also in this promising sector, both for national missions and within international cooperation. The first products of this effort are ArgoMoon and LICIACube, both 6U cubesats which operated during 2022 as first Italian spacecrafts beyond the Low Earth Orbit. The Light Italian Cubesat for Imaging of Asteroids - LICIACube participated in the NASA Double Asteroid Redirection Test - DART mission, the first active Planetary Defense mission; on September 26th 2022, few minutes after DART’s impact on asteroid Dimorphos, LICIACube captured unique images of the impact effects, primarily the plume of ejecta, and the not visible side of the secondary asteroid. The operations have been conducted by a national team coordinated by ASI. The design, manufacturing, testing and operations of the space and ground segment elements have been performed by the Italian firm Argotec under ASI management, while a wide scientific team supported the investigation preparation with impact modelling simulation and data analysis and interpretation, under the coordination of the National Institute of Astrophysics INAF. The engineering teams of Polytechnic of Milan and University of Bologna were in charge of trajectory design and optimization and the orbit determination and navigation, respectively.
Captured images during the challenging fly-by confirmed the DART success as Planetary Defense initiative and provided scientists with highly valuable data, that allowed a first set of results to be confirmed and are currently under further analysis for scientific investigations. In fact, on October 11th 2022, NASA announced the complete success of the DART mission, confirming that the spacecraft’s impact altered Dimorphos’ orbit around Didymos by 32 minutes. Moreover, The LICIACube images show that the DART impact on Dimorphos generated a cone of ejected surface material with a large aperture angle. This plume has a complex and inhomogeneous structure, characterized by non-radial filaments, dust grains, and single and clustered boulders that allows us to deeply investigate the nature of the ejecta and the structure of Dimorphos. | |
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21 Jun 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Marcos Marino, Geneva University, Switzerland | |
Resurgence | |
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27 Jun 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Kate Scholberg, Duke University USA | |
xxx | |
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28 Jun 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Kate Scholberg, Duke University, USA | |
Experiments to detect coherent neutrino nucleon scattering | |
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04 Jul 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Paul Indelicato, University of Sarbonne - France | |
Quantum electrodynamics (QED) is part of the standard model and the best understood quantum field theory. Many tests exist, from free particles (electron and muon anomalous magnetic moment) to bound states. From the historical measurement of the Lamb-shift which lead to the advent of QED and field theories, many systems have been studied and compared to the most advanced calculations. One can cite hydrogen, positronium, muonium, highly charged, few electron ions[1] and exotic atoms (atoms in which the electron is replaced by a heavier particle like a muon, a pion or an antiproton).
In this talk I will present a few cases of highly charged ions high-precision results (few ppm accuracy) obtained with our Double Crystal Spectrometer in Paris[2-4] for medium-Z elements, and preliminary results obtained at GSI on few-electron uranium. I will then present new ideas [5] and first demonstration results on QED tests using muonic atoms and transition-edge sensor micro-calorimeter at JPARC [6, 7], and their extension to antiprotonic atoms at ELENA in the future. Detailed comparison with QED and relativistic many-body calculations when relevant will be made.
[1]Topical Review: QED tests with highly-charged ions, P. Indelicato. J. Phys. B 52, 232001 (2019).
[2]High-precision measurements of n=2->n=1 transition energies and level widths in He- and Be-like Argon Ions, J. Machado, C.I. Szabo, J.P. Santos et al. Phys. Rev. A 97, 032517 (2018).
[3]Reference-free measurements of the 1s 2s 2p 2P1/2,3/2 → 1s2 2s 2S1/2 and 1s 2s 2p 4P5/2 → 1s2 2s 2S1/2 transition energies and widths in lithiumlike sulfur and argon ions, J. Machado, G. Bian, N. Paul et al. Phys. Rev. A 101, 062505 (2020).
[4]Absolute measurement of the relativistic magnetic dipole transition in He-like sulfur, J. Machado, N. Paul, G. Soum-Sidikov et al. Phys. Rev. A in press, (2023).
[5]Testing Quantum Electrodynamics with Exotic Atoms, N. Paul, G. Bian, T. Azuma et al. Phys. Rev. Lett. 126, 173001 (2021).
[6]Deexcitation Dynamics of Muonic Atoms Revealed by High-Precision Spectroscopy of Electronic K X Rays, T. Okumura, T. Azuma, D.A. Bennett et al. Phys. Rev. Lett. 127, 053001 (2021).
[7]Proof-of-Principle Experiment for Testing Strong-Field Quantum Electrodynamics with Exotic Atoms: High Precision X-ray Spectroscopy of Muonic Neon, T. Okumura, T. Azuma, D.A. Bennett et al. Phys. Rev. Lett. in press, (2023). | |
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11 Jul 2023
Physikalisches Kolloquium
Institut für Kernphysik 16:15 Uhr s.t., HS KPH |
| Prof. Susana Cardoso de Freitas, INESC MN University of Lisboa - Portugal | |
Magnetic field sensors have a mature and transversal level of implementation in the market, from automotive to biomedical domains. The impressive technological progress in thin film preparation and characterization, combined with nano-microfabrication tools offer presently large spectra for device design. The materials discussed include several varieties of thin film materials combined onto multilayer stacks. In addition, the noise mechanisms (the “killing factor” that limits the MR sensor performance) will be discussed, and I will show successful strategies for improving the signal-to-noise ratio, improving the ultimate field detectable by an MR sensor.
Examples where spintronic sensors are useful tools for precision sensing will be provided, including integration with microfluidics, optical and MEMS micromachined actuators. During my talk, I will show how challenging applications have identified creative solutions, requiring joint skills in transversal areas as physics, materials, electronics and mechanical engineering. | |
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12 Jul 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Prof. Dr. Thomas Schwetz, KIT Karlsruhe | |
Status of eV sterile neutrino oscillations in light of the new STEREO results | |
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19 Jul 2023
PRISMA+ Colloquium
Institut für Physik 13:00 Uhr s.t., Lorentz-Raum, 05-127, Staudingerweg 7 |
| Dr. Rodolfo Ferro-Hernandez, JGU Mainz | |
On the determination of Delta alpha(M_Z): comparison between methods and frameworks | |
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