A quantum beam splitter for atoms

An interferometric method is proposed to controllably split an atomic condensate in two spatial components with strongly reduced population fluctuations. All steps in our proposal are in current use in cold atom laboratories, and we show with a theoretical calculation that our proposal is very robust against imperfections of the interferometer.Comment: 6 pages, 3 figures, revtex

Positive P simulations of spin squeezing in a two-component Bose condensate

The collisional interaction in a Bose condensate represents a non-linearity which in analogy with non-linear optics gives rise to unique quantum features. In this paper we apply a Monte Carlo method based on the positive P pseudo-probability distribution from quantum optics to analyze the efficiency of spin squeezing by collisions in a two-component condensate. The squeezing can be controlled by choosing appropiate collision parameters or by manipulating the motional states of the two components.Comment: 5 pages, 2 figures. Submitted to Phys. Rev.

An Evaluation of a Behaviour Assessment to Determine the Suitability of Shelter Dogs for Rehoming

We evaluated a scheme for assessing shelter dog behaviour, which used 28 tests and rated responses from 0 (positive response) to 5 (fear, tonic immobility, or escape attempts). The assessment was evaluated for 236 dogs, and was repeated by a different assessor for 39 dogs approximately 80 days after rehoming to determine relevance of individual test components. A new owner survey evaluated satisfaction with the dog. A total of 130 of 236 dogs passed (score ≤ 70), 24 scored 71–80 (referred for behavioural modification), and 82 (score > 80) failed. Scores were mainly unaffected by dog type and environmental variables, but decreased if dog faeces from a previous test was present in the arena during a test. Shelter tests only correlated with repeat tests if there was no direct contact with assessors. Adopters were satisfied with their dogs, despite reporting some behaviour problems. The shelter assessment was therefore robust against most outside influences but did not predict responses to people well

Lapex: A Phoswich balloon experiment for hard X-ray astronomy

Satellite and balloon observations have shown that several classes of celestial objects are hard ( 15 keV) energy band with a sensitivity of approx 10 mCrab has been performed with the UCSD/MIT instrument (A4) on board the HEAO 1 satellite. About 70 X-ray sources were detected, including galactic and extragalactic objects. Hard X-ray emission has been detected in the Galaxy from X-ray pulsars. Extragalactic sources of hard X-ray emission include clusters of galaxies, QSOs, BL Lac objects, Seyfert galaxies. The essential characteristics of the Large Area Phoswich Experiment (LAPEX) for crowded sky field observations are described. It has: (1) a broad energy band of operation (20-300 keV); (2) a 3 sigma sensitivity of about 1 mCrab in 10,000 s of live observing time; and (3) imaging capabilities with an angular resolution of about 20'

Vegetation‐precipitation controls on Central Andean topography

Climatic controls on fluvial landscapes are commonly characterized in terms of mean annual precipitation. However, physical erosion processes are driven by extreme events and are therefore more directly related to the intensity, duration, and frequency of individual rainfall events. Climate also influences erosional processes indirectly by controlling vegetation. In this study, we explore how interdependent climate and vegetation properties affect landscape morphology at the scale of the Andean orogen. The mean intensity, duration, and frequency of precipitation events are derived from the TRMM 3B42v7 product. Relationships between mean hillslope gradients and precipitation event metrics, mean annual precipitation, vegetation, and bedrock lithology in the central Andes are examined by correlation analyses and multiple linear regression. Our results indicate that mean hillslope gradient correlates most strongly with percent vegetation cover ( r  = 0.56). Where vegetation cover is less than 95%, mean hillslope gradients increase with mean annual precipitation ( r  = 0.60) and vegetation cover ( r  = 0.69). Where vegetation cover is dense (>95%), mean hillslope gradients increase with increasing elevation ( r  = 0.74), decreasing inter‐storm duration ( r  = −0.69), and decreasing precipitation intensity by ~0.5°/(mm d −1 ) ( r  = −0.56). Thus, we conclude that at the orogen scale, climate influences on topography are mediated by vegetation, which itself is dependent on mean annual precipitation ( r  = 0.77). Observations from the central Andes are consistent with landscape evolution models in which hillslope gradients are a balance between rock uplift, climatic erosional efficiency and erosional resistance of the landscape determined by bedrock lithology and vegetation. Key Points Hillslope gradients in central Andes increase with increasing vegetation cover Precipitation intensity affects topography most in densely vegetated areas Mean annual precipitation affects erosional efficiency through vegetation coverPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108109/1/jgrf20258.pd

Electrical manipulation of spin states in a single electrostatically gated transition-metal complex

We demonstrate an electrically controlled high-spin (S=5/2) to low-spin (S=1/2) transition in a three-terminal device incorporating a single Mn2+ ion coordinated by two terpyridine ligands. By adjusting the gate-voltage we reduce the terpyridine moiety and thereby strengthen the ligand-field on the Mn-atom. Adding a single electron thus stabilizes the low-spin configuration and the corresponding sequential tunnelling current is suppressed by spin-blockade. From low-temperature inelastic cotunneling spectroscopy, we infer the magnetic excitation spectrum of the molecule and uncover also a strongly gate-dependent singlet-triplet splitting on the low-spin side. The measured bias-spectroscopy is shown to be consistent with an exact diagonalization of the Mn-complex, and an interpretation of the data is given in terms of a simplified effective model.Comment: Will appear soon in Nanoletter

Quantifying the role of paleoclimate and Andean Plateau uplift on river incision

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/99035/1/jgrf20055-sup-0002-2012JF002533fs02.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/99035/2/jgrf20055.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/99035/3/jgrf20055-sup-0001-2012JF002533fs01.pd

Influence of oxygen ordering kinetics on Raman and optical response in YBa_2Cu_3O_{6.4}

Kinetics of the optical and Raman response in YBa_2Cu_3O_{6.4} were studied during room temperature annealing following heat treatment. The superconducting T_c, dc resistivity, and low-energy optical conductivity recover slowly, implying a long relaxation time for the carrier density. Short relaxation times are observed for the B_{1g} Raman scattering -- magnetic, continuum, and phonon -- and the charge transfer band. Monte Carlo simulations suggest that these two relaxation rates are related to two length scales corresponding to local oxygen ordering (fast) and long chain and twin formation (slow).Comment: REVTeX, 3 pages + 4 PostScript (compressed) figure

Enabling onshore CO2 storage in Europe: fostering international cooperation around pilot and test sites

To meet the ambitious EC target of an 80% reduction in greenhouse gas emissions by 2050, CO2 Capture and Storage (CCS) needs to move rapidly towards full scale implementation with geological storage solutions both on and offshore. Onshore storage offers increased flexibility and reduced infrastructure and monitoring costs. Enabling onshore storage will support management of decarbonisation strategies at territory level while enhancing security of energy supply and local economic activities, and securing jobs across Europe. However, successful onshore storage also requires overcoming some unique technical and societal challenges. ENOS will provide crucial advances to help foster onshore CO2 storage across Europe through: 1. Developing, testing and demonstrating in the field, under "real-life conditions", key technologies specifically adapted to onshore storage. 2. Contributing to the creation of a favourable environment for onshore storage across Europe. The ENOS site portfolio will provide a great opportunity for demonstration of technologies for safe and environmentally sound storage at relevant scale. Best practices will be developed using experience gained from the field experiments with the participation of local stakeholders and the lay public. This will produce improved integrated research outcomes and increase stakeholder understanding and confidence in CO2 storage. In this improved framework, ENOS will catalyse new onshore pilot and demonstration projects in new locations and geological settings across Europe, taking into account the site-specific and local socio-economic context. By developing technologies from TRL4/5 to TRL6 across the storage lifecycle, feeding the resultant knowledge and experience into training and education and cooperating at the pan-European and global level, ENOS will have a decisive impact on innovation and build the confidence needed for enabling onshore CO2 storage in Europe. ENOS is initiating strong international collaboration between European researchers and their counterparts from the USA, Canada, South Korea, Australia and South Africa for sharing experience worldwide based on real-life onshore pilots and field experiments. Fostering experience-sharing and research alignment between existing sites is key to maximise the investment made at individual sites and to support the efficient large scale deployment of CCS. ENOS is striving to promote collaboration between sites in the world through a programme of site twinning, focus groups centered around operative issues and the creation of a leakage simulation alliance