Deterministic entanglement and tomography of ion spin qubits

We have implemented a universal quantum logic gate between qubits stored in the spin state of a pair of trapped calcium 40 ions. An initial product state was driven to a maximally entangled state deterministically, with 83% fidelity. We present a general approach to quantum state tomography which achieves good robustness to experimental noise and drift, and use it to measure the spin state of the ions. We find the entanglement of formation is 0.54.Comment: 3 figures, 4 pages, footnotes fixe

Long-lived mesoscopic entanglement outside the Lamb-Dicke regime

We create entangled states of the spin and motion of a single $^{40}$Ca$^+$ ion in a linear ion trap. The motional part consists of coherent states of large separation and long coherence time. The states are created by driving the motion using counterpropagating laser beams. We theoretically study and experimentally observe the behaviour outside the Lamb-Dicke regime, where the trajectory in phase space is modified and the coherent states become squeezed. We directly observe the modification of the return time of the trajectory, and infer the squeezing. The mesoscopic entanglement is observed up to $\Delta \alpha = 5.1$ with coherence time 170 microseconds and mean phonon excitation \nbar = 16.Comment: 5 pages, 3 figures. Revised version after editor comment

Cosmological perturbations on local systems

We study the effect of cosmological expansion on orbits--galactic, planetary, or atomic--subject to an inverse-square force law. We obtain the laws of motion for gravitational or electrical interactions from general relativity--in particular, we find the gravitational field of a mass distribution in an expanding universe by applying perturbation theory to the Robertson-Walker metric. Cosmological expansion induces an ($\ddot a/a) \vec r$ force where $a(t)$ is the cosmological scale factor. In a locally Newtonian framework, we show that the $(\ddot a/a) \vec r$ term represents the effect of a continuous distribution of cosmological material in Hubble flow, and that the total force on an object, due to the cosmological material plus the matter perturbation, can be represented as the negative gradient of a gravitational potential whose source is the material actually present. We also consider the effect on local dynamics of the cosmological constant. We calculate the perihelion precession of elliptical orbits due to the cosmological constant induced force, and work out a generalized virial relation applicable to gravitationally bound clusters.Comment: 10 page

Instabilities in the Nuclear Energy Density Functional

In the field of Energy Density Functionals (EDF) used in nuclear structure and dynamics, one of the unsolved issues is the stability of the functional. Numerical issues aside, some EDFs are unstable with respect to particular perturbations of the nuclear ground-state density. The aim of this contribution is to raise questions about the origin and nature of these instabilities, the techniques used to diagnose and prevent them, and the domain of density functions in which one should expect a nuclear EDF to be stable.Comment: Special issue "Open Problems in Nuclear Structure Theory" of Jour.Phys.G - accepted. 7 pages, 2 figure

Writing data citation guidelines for linguistics: Lessons learned

Poster presented at the RDA 14th Plenary conference, arranged by Research Data Alliance, Helsingfors, 23.10.19 - 25.10.19. https://www.rd-alliance.org/plenaries/rdas-14th-plenary-helsinki-finland. One of the main objectives of the Linguistics Data Interest Group is to develop and adopt common principles and guidelines for data citation and attribution. As a first step, the Austin Principles of Data Citation in Linguistics were published in 2018. Since then, the group has been working on developing data citation guidelines, whose target audiences are academic publishers, resource providers, and researchers who use linguistic data. --- The citation guidelines have been discussed as a work in progress on the 11th and 13th RDA plenaries, and are now more or less ready to be disseminated to the intended audiences for some final feedback. The goal is to finalise and publish the guidelines in late 2019. --- In this poster, we describe the process of developing the linguistic data citation guidelines, a process we believe is transferable to other disciplines. We share our approach to identifying discipline-specific needs while maintaining a connection to data management frameworks and principles that cross fields. We focus on our workflow and organisation, how the relevant communities have been involved in the process, what kind of challenges we have experienced, and how these have been addressed

Writing data citation guidelines for linguistics: Lessons learned

Poster presented at the RDA 14th Plenary conference, arranged by Research Data Alliance, Helsingfors, 23.10.19 - 25.10.19. https://www.rd-alliance.org/plenaries/rdas-14th-plenary-helsinki-finland. One of the main objectives of the Linguistics Data Interest Group is to develop and adopt common principles and guidelines for data citation and attribution. As a first step, the Austin Principles of Data Citation in Linguistics were published in 2018. Since then, the group has been working on developing data citation guidelines, whose target audiences are academic publishers, resource providers, and researchers who use linguistic data. --- The citation guidelines have been discussed as a work in progress on the 11th and 13th RDA plenaries, and are now more or less ready to be disseminated to the intended audiences for some final feedback. The goal is to finalise and publish the guidelines in late 2019. --- In this poster, we describe the process of developing the linguistic data citation guidelines, a process we believe is transferable to other disciplines. We share our approach to identifying discipline-specific needs while maintaining a connection to data management frameworks and principles that cross fields. We focus on our workflow and organisation, how the relevant communities have been involved in the process, what kind of challenges we have experienced, and how these have been addressed

Structural and Biophysical Insights into SPINK1 Bound to Human Cationic Trypsin

(1) The serine protease inhibitor Kazal type 1 (SPINK1) inhibits trypsin activity in zymogen granules of pancreatic acinar cells. Several mutations in the SPINK1 gene are associated with acute recurrent pancreatitis (ARP) and chronic pancreatitis (CP). The most common variant is SPINK1 p.N34S. Although this mutation was identified two decades ago, the mechanism of action has remained elusive. (2) SPINK1 and human cationic trypsin (TRY1) were expressed in E. coli, and inhibitory activities were determined. Crystals of SPINK1–TRY1 complexes were grown by using the hanging-drop method, and phases were solved by molecular replacement. (3) Both SPINK1 variants show similar inhibitory behavior toward TRY1. The crystal structures are almost identical, with minor differences in the mutated loop. Both complexes show an unexpected rotamer conformation of the His63 residue in TRY1, which is a member of the catalytic triad. (4) The SPINK1 p.N34S mutation does not affect the inhibitory behavior or the overall structure of the protein. Therefore, the pathophysiological mechanism of action of the p.N34S variant cannot be explained mechanistically or structurally at the protein level. The observed histidine conformation is part of a mechanism for SPINK1 that can explain the exceptional proteolytic stability of this inhibitor