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Sympathetic cooling of charged particles in Penning traps using electron cyclotron radiation
No full textWe present a technique for cooling arbitrary charged particles in a Penning trap by utilizing self-cooled electrons stored in a separate, macroscopically distant Penning trap as the cooling medium. The electrons decay predominantly to their motional ground state by emission of cyclotron radiation, which results in extremely low temperatures in the realm of single-digit quantum numbers in the motional degrees of freedom of the sympathetically cooled particle species. This opens up an exciting frontier of tests of fundamental physics in Penning traps. This article provides a conceptual overview as well as a quantum-mechanical description of the involved cooling dynamics. The first implementation of this technique is currently being realized at the dedicated ELCOTRAP experiment at the Max Planck Institute for Nuclear Physics, which introduces special features for a quick iterative technical development cycle. Its current status, first results from commissioning, and future prospects will be presented
Marine bacterium Kordia algicida reshapes plankton microbiome and induces metabolomic rewiring, independent of heatwave or worst-case climate scenarios
No full textFrom path diagrams to causal graphs: A structural causal perspective on cross-sectional multilevel models
No full textA supersaturated super stainless high-entropy steel with extraordinary comprehensive performances for marine application
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Why does preregistration increase the persuasiveness of evidence? A Bayesian rationalization
No full textEfficient band structure unfolding with atom-centered orbitals: General theory and application
Get PDFBand structure unfolding is a key technique for analyzing and simplifying the electronic band structure of large, internally distorted supercells that break the primitive cell's translational symmetry. In this work, we present an efficient band unfolding method for atomic orbital (AO) basis sets that explicitly accounts for both the nonorthogonality of atomic orbitals and their atom-centered nature. Unlike existing approaches that typically rely on a plane-wave representation of the (semi)valence states, we here derive analytical expressions that recast the primitive cell translational operator and the associated Bloch functions in the supercell AO basis. In turn, this enables the accurate and efficient unfolding of conduction, valence, and core states in all-electron codes, as demonstrated by our implementation in the all-electron ab initio simulation package fhi-aims, which employs numeric atom-centered orbitals. We explicitly demonstrate the capability of running large-scale unfolding calculations for systems with thousands of atoms and showcase the importance of this technique for computing temperature-dependent spectral functions in strongly anharmonic materials using CuI as example
Parallel and convergent pathways for multifeature visual processing in larval zebrafish sensorimotor decision-making
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Hybrid waveforms for precessing quasi-circular binary systems
Get PDFThe demand for long and accurate gravitational waveforms is increasing as we prepare for the next generation of detectors and seek to improve current waveform models. However, numerical relativity waveforms, while highly accurate, are often too short for these applications due to their high computational cost. Hybrid waveforms, which stitch together gravitational wave signals from different modeling approaches, provide a way to generate complete inspiral-merger-ringdown signals. While hybridization is well-established for aligned-spin systems, precession introduces additional complexities due to gauge ambiguities, frame dependence, or spin dynamics. Here we study the challenges associated with alignment of precessing waveforms and present a systematic approach for constructing hybrid waveforms of precessing quasi-circular systems. Our approach relies on minimal assumptions about the merger waveforms and employs the quadrupole-aligned frame to mitigate mode-mixing. Our method is designed to be robust and broadly applicable, imposing minimal constraints on the input waveforms. This framework expands the applicability of hybridization techniques, facilitating flexible hybrid construction for parameter estimation, model calibration, and gravitational-wave data analysis