Experimental and theoretical investigation of a multi-mode cooling scheme using multiple EIT resonances

We introduce and demonstrate double-bright electromagnetically induced transparency (D-EIT) cooling as a novel approach to EIT cooling. By involving an additional ground state, two bright states can be shifted individually into resonance for cooling of motional modes of frequencies that may be separated by more than the width of a single EIT cooling resonance. This allows three-dimensional ground state cooling of a $^{40}$Ca$^+$ ion trapped in a linear Paul trap with a single cooling pulse. Measured cooling rates and steady-state mean motional quantum numbers for this D-EIT cooling are compared with those of standard EIT cooling as well as concatenated standard EIT cooling pulses for multi-mode cooling. Experimental results are compared to full density matrix calculations. We observe a failure of the theoretical description within the Lamb-Dicke regime that can be overcome by a time-dependent rate theory. Limitations of the different cooling techniques and possible extensions to multi-ion crystals are discussed.Comment: 18 pages, 13 figures. We have decided to merge the contents of our submission arXiv:1711.00738 with this paper into one comprehensive work. New titl

Direction Specific Ambisonics Source Separation with End-To-End Deep Learning

Ambisonics is a scene-based spatial audio format that has several useful features compared to object-based formats, such as efficient whole scene rotation and versatility. However, it does not provide direct access to the individual source signals, so that these have to be separated from the mixture when required. Typically, this is done with linear spherical harmonics (SH) beamforming. In this paper, we explore deep-learning-based source separation on static Ambisonics mixtures. In contrast to most source separation approaches, which separate a fixed number of sources of specific sound types, we focus on separating arbitrary sound from specific directions. Specifically, we propose three operating modes that combine a source separation neural network with SH beamforming: refinement, implicit, and mixed mode. We show that a neural network can implicitly associate conditioning directions with the spatial information contained in the Ambisonics scene to extract specific sources. We evaluate the performance of the three proposed approaches and compare them to SH beamforming on musical mixtures generated with the musdb18 dataset, as well as with mixtures generated with the FUSS dataset for universal source separation, under both anechoic and room conditions. Results show that the proposed approaches offer improved separation performance and spatial selectivity compared to conventional SH beamforming.Comment: To be published in Acta Acustica. Code and listening examples: https://github.com/francesclluis/direction-ambisonics-source-separatio

Towards Managing the Migration to Post-Quantum-Cryptography

As soon as cryptographically relevant quantum computers exist, they can break today's prevalent asymmetric cryptographic algorithms. Organizations (and the IT society) have to plan on migrating to quantum-resilient cryptographic measures, also known as post-quantum cryptography (PQC). However, this is a difficult task, and to the best of our knowledge, there is no generalized approach to manage such a complex migration for cryptography used in IT systems. PMMP helps organizations manage the migration to PQC and establish crypto-agility. Having finished the initial theoretical design phase, we are now looking to promote PMMP to encourage practitioners to join the effort and work with us to develop it further.Comment: 20 page

Equipment to tag, track and collect biopsies from whales and dolphins : the ARTS, DFHorten and LKDart systems

Funding Information: A special thanks to all the members of the 3S team, and to FFI, for support during the development of the ARTS–DTAG setup. Furthermore, special acknowledgement to ICR (Institute of Cetacean Research, Japan) for the development of the new ARTS carrier (ARTSTBC).Of all animals considered subjects for instrumentation for behavioral or physiological studies, cetaceans probably represent the greatest challenge to the engineer and biologist. The marine environment being harsh to electronics, evasive behavior during tagging approaches and the short time window available to attach instruments, all imply a need for innovative tagging solutions to facilitate better understanding of their life cycle, migration, physiology, behavior, health and genetics. Several animal-attached tag packages holding specific data loggers, e.g., time depth recorders, position, orientation, acoustic and video recorders for short to medium term studies, as well as tags developed for large scale migration telemetry studies are available as off-the-shelf devices, or in many cases as custom made sensor packages. Deployment of those instruments is often the limiting factor for data collection. The Aerial Remote Tag System (ARTS) is a flexible system which can easily be adapted to deploy different tag sensor packages and biopsy collection devices. This paper presents the history and design of the ARTS, and accessories developed for instrumentation and biopsy sampling of cetaceans, such as the recent developed ARTS–LKDart for biopsy sampling. Deployment of archival tags usually requires radio tracking of the instrumented animal, or at least tracking of the tag for recovery. Thus, we also here describe the automatic digital signal processing radio direction finder, the Direction Finder Horten (DFHorten unit).Publisher PDFPeer reviewe

Formal Insertion of Alkenes Into C(sp3)−F Bonds Mediated by Fluorine-Hydrogen Bonding

C−F Insertion reactions represent an attractive approach to prepare valuable fluorinated compounds. The high strength of C−F bonds and the low reactivity of the fluoride released upon C−F bond cleavage, however, mean that examples of such processes are extremely scarce in the literature. Here we report a reaction system that overcomes these challenges using hydrogen bond donors that both activate C−F bonds and allow for downstream reactions with fluoride. In the presence of hexafluoroisopropanol, benzyl and propargyl fluorides undergo efficient formal C−F bond insertion across α-fluorinated styrenes. This process, which does not require any additional fluorinating reagent, occurs under mild conditions and delivers products featuring the gem-difluoro motif, which is attracting increasing interest in medicinal chemistry. Moreover, readily available organic bromides can be engaged directly in a one-pot process that avoids the isolation of organic fluorides