Narrow Line Photoassociation in an Optical Lattice

With ultracold $^{88}$Sr in a 1D magic wavelength optical lattice, we performed narrow line photoassociation spectroscopy near the $^1$S$_0 - ^3$P$_1$ intercombination transition. Nine least-bound vibrational molecular levels associated with the long-range $0_u$ and $1_u$ potential energy surfaces were measured and identified. A simple theoretical model accurately describes the level positions and treats the effects of the lattice confinement on the line shapes. The measured resonance strengths show that optical tuning of the ground state scattering length should be possible without significant atom loss.Comment: 4 pages, 4 figure

An Investigation of Behavioural and Self-Reported Cognitive Empathy Deficits in Adolescents With Autism Spectrum Disorders and Adolescents With Behavioural Difficulties

© 2021 Vilas, Reniers and Ludlow. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). https://creativecommons.org/licenses/by/4.0/Deficits in empathy have been considered hallmarks in individuals with autism spectrum disorders (ASD) but are also considered to underlie antisocial behaviour associated with individuals with callous unemotional traits (CU). Research has suggested that individuals with autism spectrum disorders show more difficulties with cognitive empathy, and that individuals diagnosed with behaviours difficulties, characterised by CU traits and antisocial behaviour, demonstrate low affective empathy. In the current manuscript we present findings of two studies. The first study describes the validation of a new stimulus set developed for the empathic accuracy task, focused on its cognitive component. The second study compares the performance of 27 adolescents with ASD, 27 age matched typically developing adolescents and 17 adolescents with behavioural difficulties on the empathic accuracy task and a self-report measure of empathy. While, no differences were observed between the three groups across the empathy accuracy task, the adolescents with ASD and CD showed deficits in their cognitive empathy across the self-report measure. Adolescents with ASD showed lower scores in particularly their perspective taking abilities, whereas the adolescences with behavioural difficulties showed more difficulties with their online simulation. No differences in self-reported affective empathy across the three groups were observed. Clinical implications of the findings are discussed.Peer reviewedFinal Published versio

Narrow Line Cooling: Finite Photon Recoil Dynamics

We present an extensive study of the unique thermal and mechanical dynamics for narrow-line cooling on the 1S0 - 3P1 88Sr transition. For negative detuning, trap dynamics reveal a transition from the semiclassical regime to the photon-recoil-dominated quantum regime, yielding an absolute minima in the equilibrium temperature below the single-photon recoil limit. For positive detuning, the cloud divides into discrete momentum packets whose alignment mimics lattice points on a face-centered-cubic crystal. This novel behavior arises from velocity selection and "positive feedback" acceleration due to a finite number of photon recoils. Cooling is achieved with blue-detuned light around a velocity where gravity balances the radiative force.Comment: 4 pages, 3 figures, Phys. Rev. Lett., in pres

The physical drivers of gas turbulence in simulated disc galaxies

We use the EAGLE cosmological simulations to study the evolution of the vertical velocity dispersion of cold gas, $\sigma_{z}$, in central disc galaxies and its connection to stellar feedback, gravitational instabilities, cosmological gas accretion and galaxy mergers. To isolate the impact of feedback, we analyse runs that turn off stellar and (or) AGN feedback in addition to a run that includes both. The evolution of $\sigma_z$ and its dependence on stellar mass and star formation rate in EAGLE are in good agreement with observations. Galaxies hosted by haloes of similar virial mass, $\rm M_{200}$, have similar $\sigma_z$ values even in runs where feedback is absent. The prevalence of local instabilities in discs is uncorrelated with $\sigma_z$ at low redshift and becomes only weakly correlated at high redshifts and in galaxies hosted by massive haloes. $\sigma_z$ correlates most strongly with the specific gas accretion rate onto the disc as well as with the degree of misalignment between the inflowing gas and the disc's rotation axis. These correlations are significant across all redshifts and halo masses, with misaligned accretion being the primary driver of high gas turbulence at redshifts $z \lesssim 1$ and for halo masses $\rm M_{200} \lesssim 10^{11.5} M_{\odot}$. Galaxy mergers increase $\sigma_z$, but because they are rare in our sample, they play only a minor role in its evolution. Our results suggest that the turbulence of cold gas in EAGLE discs results from a complex interplay of different physical processes whose relative importance depends on halo mass and redshift.Comment: 22 pages, 12 figures. Accepted for publication in MNRA

A statistical-mechanical explanation of dark matter halo properties

Cosmological N-body simulations have revealed many empirical relationships of dark matter halos, yet the physical origin of these halo properties still remains unclear. On the other hand, the attempts to establish the statistical mechanics for self-gravitating systems have encountered many formal difficulties, and little progress has been made for about fifty years. The aim of this work is to strengthen the validity of the statistical-mechanical approach we have proposed previously to explain the dark matter halo properties. By introducing an effective pressure instead of the radial pressure to construct the specific entropy, we use the entropy principle and proceed in a similar way as previously to obtain an entropy stationary equation. An equation of state for equilibrated dark halos is derived from this entropy stationary equation, by which the dark halo density profiles with finite mass can be obtained. We also derive the anisotropy parameter and pseudo-phase-space density profile. All these predictions agree well with numerical simulations in the outer regions of dark halos. Our work provides further support to the idea that statistical mechanics for self-gravitating systems is a viable tool for investigation.Comment: 5 pages, 4 figures, Accepted by A&

Identifying the disc, bulge, and intra-halo light of simulated galaxies through structural decomposition

We perform a structural decomposition of galaxies identified in three cosmological hydrodynamical simulations by applying Gaussian Mixture Models (GMMs) to the kinematics of their stellar particles. We study the resulting disc, bulge, and intra-halo light (IHL) components of galaxies whose host dark matter haloes have virial masses in the range $M_{200}=10^{11}$-- $10^{15}\,{\rm M_\odot}$. Our decomposition technique isolates galactic discs whose mass fractions, $f_{\rm disc}$, correlate strongly with common alternative morphology indicators; for example, $f_{\rm disc}$ is approximately equal to $\kappa_{{\rm co}}$, the fraction of stellar kinetic energy in co-rotation. The primary aim of our study, however, is to characterise the IHL of galaxies in a consistent manner and over a broad mass range, and to analyse its properties from the scale of galactic stellar haloes up to the intra-cluster light. Our results imply that the IHL fraction, $f_{\rm IHL}$, has appreciable scatter and is strongly correlated with galaxy morphology: at fixed stellar mass, the IHL of disc galaxies is typically older and less massive than that of spheroids. Above $M_{200}\approx 10^{13}\,{\rm M_\odot}$, we find, on average, $f_{\rm IHL}\approx 0.45$, albeit with considerable scatter. The transition radius beyond which the IHL dominates the stellar mass of a galaxy is roughly $30\,{\rm kpc}$ for $M_{200}\lesssim 10^{12.8}\,{\rm M_\odot}$, but increases strongly towards higher masses. However, we find that no alternative IHL definitions -- whether based on the ex-situ stellar fraction, or the stellar mass outside a spherical aperture -- reproduce our dynamically-defined IHL fractions.Comment: 17 pages, 12 figures, submitted to MNRA

An immunotherapy survivor population: health-related quality of life and toxicity in patients with metastatic melanoma treated with immune checkpoint inhibitors

© The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Purpose The immune checkpoint inhibitors (ICIs) have resulted in subgroups of patients with metastatic melanoma achievinghigh-quality durable responses. Metastatic melanoma survivors are a new population in the era of cancer survivorship. The aimofthis study was to evaluate metastatic melanoma survivors in terms of health-related quality of life (HRQoL), immune-relatedadverse events (irAEs) and exposure to immunosuppressive agents in a large single centre in the UK.Methods We defined the survivor population as patients with a diagnosis of metastatic melanoma who achieved a durableresponse to an ICI and had been followed-up for a minimum of 12 months from initiation of ICI without disease progression.HRQoL was assessed using SF-36. Electronic health records were accessed to collect data on demographics, treatments, irAEsand survival. HRQoL data was compared with two norm-based datasets.Results Eighty-four metastatic melanoma survivors were eligible and 87% (N = 73) completed the SF-36. ICI-related toxicity ofany grade occurred in 92%of patients and 43%had experienced a grade 3 or 4 toxicity. Almost half (49%) of the patients requiredsteroids for the treatment of ICI-related toxicity, whilst 14% required treatment with an immunosuppressive agent beyondsteroids.Melanoma survivors had statistically significant lower HRQoL scores with regard to physical, social and physical rolefunctioning and general health compared with the normative population. There was a trend towards inferior scores in patientswith previous exposure to ipilimumab compared with those never exposed to ipilimumab.Conclusions Our results show that metastatic melanoma survivors have potentially experienced significant ICI-related toxicityand experience significant impairments in specific HRQoL domains. Future service planning is required to meet this population’sunique survivorship needs.Peer reviewe