Quantum Spin Dimers from Chiral Dissipation in Cold-Atom Chains

We consider the non-equilibrium dynamics of a driven dissipative spin chain with chiral coupling to a 1D bosonic bath, and its atomic implementation with a two-species mixture of cold quantum gases. The reservoir is represented by a spin-orbit coupled 1D quasi-condensate of atoms in a magnetized phase, while the spins are identified with motional states of a separate species of atoms in an optical lattice. The chirality of reservoir excitations allows the spins to couple differently to left and right moving modes, which in our atomic setup can be tuned from bidirectional to purely unidirectional. Remarkably, this leads to a pure steady state in which pairs of neighboring spins form dimers that decouple from the remainder of the chain. Our results also apply to current experiments with two-level emitters coupled to photonic waveguides.Comment: Replaced by published version (6 pages + 8 pages supplemental material

Routine Changing of Intravenous Administration Sets Does Not Reduce Colonization or Infection in Central Venous Catheters

Objective: To determine the effect of routine intravascular administration-set changes on central venous catheter (CVC) colonization and catheter related bacteremia (CRB). Design: Prospective, randomised controlled trial Setting: 18-bed ICU in a University-affiliated, tertiary referral hospital. Participants: 404 chlorhexidine and silver sulfadiazine coated multi-lumen CVCs from 251 intensive care unit (ICU) patients. Interventions: After ethical approval, CVCs inserted in ICU and in situ on Day 4 were randomised to have their administration-sets changed on Day 4 (n = 203) or not at all (n = 201). Fluid container and blood product administration-set use was limited to 24 hours. CVCs were removed (Day 7, not required or suspected infection), and cultured for colonization ( 15 cfu). Medical and laboratory staff were blinded. CRB was diagnosed by a blinded intensivist using strict definitions. Data was collected on; catheter life, CVC site, APACHE II score, patient age, diagnosis, hyperglycemia, hypoalbuminemia, immune status, number of fluid containers and intravenous injections, propofol, blood, TPN or lipid infusion. Results: There were 10 colonized CVCs in the set change group and 19 in the no change group. This was not a statistically significant difference on Kaplan Meier survival analysis (Effect Size = 0.09, Log Rank = 0.87, df = 1, p = 0.35). There were 3 cases of CRB per group. Logistic regression found that burns diagnosis and increased ICU stay were the only factors that significantly predicted colonization (p < 0.001). Conclusions: Intravenous administration-sets can be used for 7-days. Routine administration-set changes are unnecessary before this time

Quantum computing with alkaline earth atoms

We present a complete scheme for quantum information processing using the unique features of alkaline earth atoms. We show how two completely independent lattices can be formed for the $^1$S$_0$ and $^3$P$_0$ states, with one used as a storage lattice for qubits encoded on the nuclear spin, and the other as a transport lattice to move qubits and perform gate operations. We discuss how the $^3$P$_2$ level can be used for addressing of individual qubits, and how collisional losses from metastable states can be used to perform gates via a lossy blockade mechanism.Comment: 4 pages, 3 figures, RevTeX

Thermal vs. Entanglement Entropy: A Measurement Protocol for Fermionic Atoms with a Quantum Gas Microscope

We show how to measure the order-two Renyi entropy of many-body states of spinful fermionic atoms in an optical lattice in equilibrium and non-equilibrium situations. The proposed scheme relies on the possibility to produce and couple two copies of the state under investigation, and to measure the occupation number in a site- and spin-resolved manner, e.g. with a quantum gas microscope. Such a protocol opens the possibility to measure entanglement and test a number of theoretical predictions, such as area laws and their corrections. As an illustration we discuss the interplay between thermal and entanglement entropy for a one dimensional Fermi-Hubbard model at finite temperature, and its possible measurement in an experiment using the present scheme

The Well-Being of Adolescents in Northern Canada

Poster Presentation The Territorial North (i.e. Yukon, Northwest Territories, Nunavut) is markedly different from the rest of Canada; yet there is little statistically reliable information about adolescent well-being in the region. The objective of this paper is to create a portrait of adolescent well-being in the Territorial North relative to Southern Canada. We do so using the Canadian Community Health Survey, a nationally representative dataset. We examine seven domains of well-being with 23 indicators by region and Aboriginal identity for youth aged 12 to 17. We include objective and subjective measures, reflecting the importance of adolescents’ perspectives in studies of their own well-being. We find negligible differences among the non-Aboriginal population; while most indicators are substantially worse for Aboriginal youth, especially in Northern Canada (e.g. income, poverty, household education, family structure, crowding, food insecurity, exposure to second-hand smoke, school enrolment, smoking, sexual activity, obesity and overweight, oral and mental health). However, there are exceptions (e.g. physical activity, fruit and vegetable consumption, stress, body image, belonging). Nevertheless, Aboriginal youth in the North are generally less satisfied with life. This is not surprising since they fare worse in most well-being indicators considered in this study

Dressed, noise- or disorder- resilient optical lattices

External noise is inherent in any quantum system, and can have especially strong effects for systems exhibiting sensitive many-body phenomena. We show how a dressed lattice scheme can provide control over certain types of noise for atomic quantum gases in the lowest band of an optical lattice, removing the effects of lattice amplitude noise to first order for particular choices of the dressing field parameters. We investigate the non-equilibrium many-body dynamics for bosons and fermions induced by noise away from this parameter regime, and also show how the same technique can be used to reduce spatial disorder in projected lattice potentials.Comment: 4+ Pages, 4 Figure

Mind the gap:The global governance of just transitions

Transitions away from fossil fuels need to be governed, financed, regulated and coordinated, patterns of production and innovation need to be steered and shaped by rulemaking bodies at all levels of authority. For this to happen across a highly uneven international system, global institutions have a vital role to play in supporting and implementing just transitions (JTs) that align with principles addressing the procedural, distributional, intergenerational and recognition-based aspects of justice and which help to address the temporal and spatial aspects of transitions. In this paper, we review the ways in which global institutions are involved in the governance of JTs. We illustrate the roles these institutions are playing through three key areas vital to JTs: the (i) governance of finance (ii) labour protection and (iii) mobilising alternatives. To make sense of the diverse and uneven nature of these engagements and their implications, we explore in turn four key gaps in the way global institutions are approaching the issue of JTs.</p

Mind The Gap: The Global Governance of Just Transitions

Just transitions to a greener economy need to be governed and regulated, and there is a variety of multilateral and international institutions with responsibilities for finance, labour and technology development. Based on a analysis of some of the key actors in this space — such as the IMF, ILO and IRENA — we identify a series of ‘gaps’ in how just transitions are defined, promoted and financed. This creates an increasingly fragmented landcape of international policy advocacy, making it more difficult for national governments to navigate the complexity of just transitions. This also makes future-oriented policies that aim at shared prosperity and sustainability more challenging, while largely reinforcing a dominant neo-liberal and financialised economic growth model. For global institutions to play a more active and inclusive role in supporting just transitions in the context of uneven development and stark global inequalities, they need to address questions of justice head on, and institutions with explicit social and environmental justice goals need to be prioritised

Sequence of post-moult exoskeleton hardening preserved in a trilobite mass moult assemblage from the Lower Ordovician Fezouata Konservat-Lagerstätte, Morocco

Euarthropods have a tough exoskeleton that provides crucial protection from predation and parasitism. However, this is restrictive to growth and must be periodically moulted. The moulting sequence is well-known from extant arthropods, consisting of: (i) the long inter-moult stage, in which no changes occur to the hardened exoskeleton; (ii) the pre-moult stage where the old exoskeleton is detached and the new one secreted; (iii) exuviation, when the old exoskeleton is moulted; and (iv) the post-moult stage during which the new exoskeleton starts as soft, thin, and partially compressed and gradually hardens to the robust exoskeleton of the inter-moult stage. Trilobite fossils typically consist of inter-moult carcasses or moulted exuviae, but specimens preserving the post-moult stage are rare. Here we describe nine specimens assigned to Symphysurus ebbestadi representing the first group of contemporaneous fossils collected that preserve all key stages of the moulting process in one taxon, including the post-moult stage. They were collected from a single lens in the Tremadocian part of the Fezouata Shale Formation, Morocco. Based on cephalic displacement and comparison to other trilobite moults, one specimen appears to represent a moulted exoskeleton. Four specimens are typical inter-moult carcasses. Four others are wrinkled and flattened, with thin exoskeletons compared to inter-moult specimens, and are considered post-moult individuals. These S. ebbestadi specimens illuminate the preservation and morphology of the post-moulting stage, characterised by strong anterior-posterior exoskeleton wrinkling, as well as overall body flattening and reduced visibility of thoracic articulations. Being found in the same lens, these specimens likely represent the first preserved in-the-act mass moulting event. The displayed sequence of moulting suggests the moulting process in trilobites was comparable to modern arthropods, and conserved within euarthropod evolutionary history

Quantum optics of chiral spin networks

We study the driven-dissipative dynamics of a network of spin-1/2 systems coupled to one or more chiral 1D bosonic waveguides within the framework of a Markovian master equation. We determine how the interplay between a coherent drive and collective decay processes can lead to the formation of pure multipartite entangled steady states. The key ingredient for the emergence of these many-body dark states is an asymmetric coupling of the spins to left and right propagating guided modes. Such systems are motivated by experimental possibilities with internal states of atoms coupled to optical fibers, or motional states of trapped atoms coupled to a spin-orbit coupled Bose-Einstein condensate. We discuss the characterization of the emerging multipartite entanglement in this system in terms of the Fisher information