A5031416477- Ionosphere and magnetosphere dynamics
- Quantum Mechanics and Applications
- Geomagnetism and Paleomagnetism Studies
- Solar and Space Plasma Dynamics
- Quantum Information and Cryptography
- Earthquake Detection and Analysis
- Quantum Electrodynamics and Casimir Effect
- Advanced Thermodynamics and Statistical Mechanics
- Complex Network Analysis Techniques
- Opinion Dynamics and Social Influence
- Quantum Computing Algorithms and Architecture
- Spectroscopy and Quantum Chemical Studies
- Mechanical and Optical Resonators
- Thermal Radiation and Cooling Technologies
- Marine and coastal ecosystems
- Atmospheric Ozone and Climate
- Geophysics and Gravity Measurements
- Climate variability and models
- Astro and Planetary Science
- Atmospheric and Environmental Gas Dynamics
- Quantum and Classical Electrodynamics
- Noncommutative and Quantum Gravity Theories
- Cardiovascular Health and Disease Prevention
- Industrial Gas Emission Control
- Atomic and Subatomic Physics Research
GFZ Helmholtz Centre for Geosciences
2018-2023
Meta (United States)
2023
University of Potsdam
2016
Institute for Cross-Disciplinary Physics and Complex Systems
2014-2015
IFP Énergies nouvelles
2014
University of Nottingham
2012-2013
University of Turku
2008-2011
Turku Centre for Computer Science
2011
University of Palermo
2008
National Interuniversity Consortium for the Physical Sciences of Matter
2008
We address continuous-variable quantum key distribution (QKD) in non-Markovian lossy channels and show how the features may be exploited to enhance security and/or detect presence position of an eavesdropper along transmission line. In particular, we suggest a coherent-state QKD protocol which is secure against Gaussian individual attacks based on optimal $1\ensuremath{\rightarrow}2$ asymmetric cloning machines for arbitrarily low values overall The scheme relies specific properties, cannot...
We introduce a non-Markovianity measure for continuous variable open quantum systems based on the idea put forward in H.-P. Breuer et al., Phys. Rev. Lett.\textbf{103}, 210401 (2009), i.e., by quantifying flow of information from environment back to system. Instead trace distance we use here fidelity assess distinguishability states. employ our evaluate two paradigmatic Gaussian channels: purely damping channel and Brownian motion with Ohmic environment. consider different classes states...
We consider two identical and non-interacting harmonic oscillators coupled to either independent bosonic baths or a common bath. Under the only assumption of weak coupling, we analyze in details non-Markovian short time-scale evolution intensity correlations, entanglement quantum discord for initial two-mode squeezed-thermal vacuum states. In reservoirs case observe detrimental effect environment all these quantities establish hierarchy their robustness against environmental noise. reservoir...
Abstract Geomagnetic indices are convenient quantities that distill the complicated physics of some region or aspect near‐Earth space into a single parameter. Most best‐known calculated from ground‐based magnetometer data sets, such as Dst, SYM‐H, Kp, AE, AL, and PC. Many models have been created predict values these indices, often using solar wind measurements upstream Earth input variables to calculation. This document reviews current state geomagnetic methods used assess their ability...
Abstract Van Allen Probes measurements revealed the presence of most unusual structures in ultra‐relativistic radiation belts. Detailed modeling, analysis pitch angle distributions, difference between relativistic and ultra‐realistic electron evolution, along with theoretical studies scattering wave growth, all indicate that electromagnetic ion cyclotron (EMIC) waves can produce a very efficient loss electrons heart Moreover, detailed profiles phase space densities provides direct evidence...
We investigate a family of qubit-oscillator states as resources for hybrid quantum communication. They result from mechanism qubit-controlled displacement on the oscillator. For large displacements, we obtain analytical formulas entanglement and other nonclassical correlations, such entropic geometric discord, in those states. design two protocols communication using considered resource states: teleportation remote-state preparation. The latter, its standard formulation, is shown to have...
We consider paths in weighted and directed temporal networks, introducing tools to compute sets of high probability. quantify the relative importance most probable path between two nodes with respect whole set a subset highly that incorporate connection These concepts are used provide alternative definitions betweenness centrality. apply our formalism transport network describing surface flow Mediterranean sea. Despite full dynamics is described by very large number we find that, for...
Abstract. We present the toolbox ClimateLearn to tackle problems in climate prediction using machine learning techniques and network analysis. The package allows basic operations of data mining, i.e. reading, merging, cleaning data, running algorithms such as multilayer artificial neural networks symbolic regression with genetic programming. Because spatial temporal information on variability can be efficiently represented by complex measures, are considered here input machine-learning...
We address the evolution of entanglement in bimodal continuous variable quantum systems interacting with two independent structured reservoirs. derive an analytic expression for formation without performing Markov and secular approximations study details dynamics various types reservoirs different reservoir temperatures, assuming modes initially excited a twin-beam state. Our solution allows us to identify three dynamical regimes characterized by behaviors entanglement: sudden death,...
Non-homogeneous chain environments (e.g. segmented ion traps) are investigated through an exact diagonalization approach. Different spectral densities, including band-gaps, can be engineered to separately assess memory effects. Environment non-Markovianity is quantified with recently introduced measures of information flow-back and non-divisibility the system dynamical map. By sweeping bath spectrum via tuning frequency we show strongest effect at band-gap edges provide interpretation based...
Abstract Current algorithms for the real‐time prediction of K p index use a combination models empirically driven by solar wind measurements at L1 Lagrange point and historical values index. In this study, we explore limitations approach, examining forecast short long lead times using time series as input to artificial neural networks. We relative efficiency wind‐based predictions, predictions based on recurrence, persistence. Our modeling results show that short‐term forecasts approximately...
Abstract The Kp index is a measure of the midlatitude global geomagnetic activity and represents short‐term magnetic variations driven by solar wind plasma interplanetary field. one most widely used indicators for space weather alerts serves as input to various models, such thermosphere radiation belts. It therefore crucial predict accurately. Previous work in this area has mostly employed artificial neural networks nowcast Kp, based their inferences on recent history measurements at L1. In...
We propose a modified metric based on the Hilbert-Schmidt norm and adopt it to define rescaled version of geometric measure quantum discord. Such is found not suffer from pathological dependence state purity. Although employed still noncontractive under operations, we show that resulting indicator correlations in agreement with other bona fide discord measures number physical examples. present critical assessment requirements reliability versus computability when approaching task...
Space weather driven atmospheric density variations affect low Earth orbit (LEO) satellites during all phases of their operational lifetime. Rocket launches, re-entry events and space debris are also similarly affected. A better understanding processes impact on is thus critical for satellite operations as well safety issues. The Horizon 2020 project Weather Atmosphere Model Indices (SWAMI) project, which started in January 2018, aims to enhance this by: Developing improved neutral...
Abstract Following the end of Van Allen Probes mission, Arase satellite offers a unique opportunity to continue in‐situ radiation belt and ring current particle measurements into next solar cycle. In this study we compare spin‐averaged flux from MEPe, HEP‐L, HEP‐H, XEP‐SSD instruments on with those MagEIS REPT Probes, calculating Pearson correlation coefficient mean ratio fluxes at L* conjunctions between spacecraft. show close agreement over wide range energies, observing similar general...
The study of connectivity patterns in networks has brought novel insights across diverse fields ranging from neurosciences to epidemic spreading or climate. In this context, betweenness centrality demonstrated be a very effective measure identify nodes that act as focus congestion, bottlenecks, the network. However, there is not way define outside network framework. By analytically linking dynamical systems and theory, we provide trajectory-based formulation betweenness, called Lagrangian...
Accurate forecasts of thermosphere densities, realistic calculation aerodynamic drag, and propagation the uncertainty on predicted orbit positions are required for conjunction analysis collision avoidance decision making. The main focus Committee Space Research (COSPAR) International Weather Action Teams (ISWAT) involved in atmosphere variability studies is satellite this paper reviews our current capabilities lists recommendations. density models due to combined effect employing simplified...
The time-dependent Casimir-Polder force arising during the time evolution of an initially bare two-level atom, interacting with radiation field and placed near a perfectly conducting wall, is considered. Initially electromagnetic supposed to be in vacuum state atom its ground state. analytical expression as function atom-wall distance evaluated from atom-field interaction energy. Physical features limits validity results are discussed detail.
We study the time evolution of Casimir-Polder force acting on a neutral atom in front perfectly conducting plate, when system starts its unitary from partially dressed state. solve Heisenberg equations for both atomic and field quantum operators, exploiting series expansion with respect to electric charge an iterative technique. After discussing behavior time-dependent initially atom, we analyze possible experimental scheme prepare state observability this new dynamical effect.
A Lagrangian flow network is constructed for the atmospheric blocking of Eastern Europe and Western Russia in summer 2010. We compute most probable paths followed by fluid particles, which reveal Omega-block skeleton event. hierarchy sets highly introduced to describe transport pathways when path alone not representative enough. These have shape narrow coherent tubes flowing close one. Thus, even very significant terms its probability, it still identifies geometry pathways.
We consider the dynamical atom-surface Casimir-Polder force in nonequilibrium configuration of an atom near a perfectly conducting wall, initially prepared excited state with field its vacuum state. evaluate time-dependent on and find that it shows oscillatory behavior from attractive to repulsive both time space. also investigate asymptotic related local quantities, showing static value force, as obtained by time-independent approach, is recovered for times much longer than scale atomic...
Abstract There have been a number of theories proposed concerning the loss relativistic electrons from radiation belts. However, direct observations were not possible on previous missions due to large field view instruments and often high‐altitude orbits satellites that did allow researchers isolate precipitating stably trapped. We use measurements ELFIN‐L suit flown Lomonosov spacecraft at LEO orbit, which allows us distinguish trapped drift cone electrons. The sun‐synchronous orbit...
We review a recently developed theoretical approach to the experimental detection and quantification of bipartite quantum correlations between qubit d dimensional system. Specifically, introducing properly designed measure Q, presented scheme allows us quantify general for arbitrary states 2 x systems without need fully reconstruct them by tomographic techniques. take in exam specifics required architecture nuclear magnetic resonance optical settings. Finally we extend this models open...
We review different aspects of atom–atom and atom–wall Casimir–Polder forces. first discuss the role a boundary condition on interatomic potential between two ground-state atoms, give physically transparent interpretation results in terms vacuum fluctuations image atomic dipoles. then known force for ground- excited-state using method which is also suited to extension time-dependent situations. Finally, we consider fluctuation atom conducting wall, possible observation this fluctuation.
We consider the time evolution of electric and magnetic field operators for a two-level atom, interacting with electromagnetic field, placed near an infinite perfectly conducting wall. solve iteratively Heisenberg equations obtain energy density around atom (valid any initial state). Then we explicitly evaluate them state in its bare ground vacuum state. show that results can be physically interpreted as superposition fields propagating directly from reflected on Relativistic causality...