Quantum Enhanced Multiple Phase Estimation

We study the simultaneous estimation of multiple phases as a discretised model for the imaging of a phase object. We identify quantum probe states that provide an enhancement compared to the best quantum scheme for the estimation of each individual phase separately, as well as improvements over classical strategies. Our strategy provides an advantage in the variance of the estimation over individual quantum estimation schemes that scales as O(d) where d is the number of phases. Finally, we study the attainability of this limit using realistic probes and photon-number-resolving detectors. This is a problem in which an intrinsic advantage is derived from the estimation of multiple parameters simultaneously.Comment: Accepted by Physical Review Letter

Kinematics of a hot massive accretion disk candidate

Characterizing rotation, infall and accretion disks around high-mass protostars is an important topic in massive star formation research. With the Australia Telescope Compact Array and the Very Large Array we studied a massive disk candidate at high angular resolution in ammonia (NH3(4,4) & (5,5)) tracing the warm disk but not the envelope. The observations resolved at ~0.4'' resolution (corresponding to ~1400AU) a velocity gradient indicative of rotation perpendicular to the molecular outflow. Assuming a Keplerian accretion disk, the estimated protostar-disk mass would be high, similar to the protostellar mass. Furthermore, the position-velocity diagram exhibits additional deviation from a Keplerian rotation profile which may be caused by infalling gas and/or a self-gravitating disk. Moreover, a large fraction of the rotating gas is at temperatures >100K, markedly different to typical low-mass accretion disks. In addition, we resolve a central double-lobe cm continuum structure perpendicular to the rotation. We identify this with an ionized, optically thick jet.Comment: 5 pages, 3 figures, accepted for Astrophysical Journal Letters, a high-resolution version of the draft can be found at http://www.mpia.de/homes/beuther/papers.htm

Governance implications of the UN Higher Education Sustainability Initiative

The Higher Education Sustainability Initiative (HESI, 2017a) states that higher education institutions (HEIs) are integrating the SDGs into sustainability strategies in the form of research, teaching, pedagogy, and campus practices, and to position HEIs as key drivers for achieving the UN Sustainable Development Goals (SDGs). Concern has been raised (HESI, 2017b) as to the potential impact of HEIs in helping to achieve the SDGs; the challenges faced by HEIs with integrating the SDGs into curriculum and institutional strategies; the role of partnerships for HEIs among students, faculty, government, and various stakeholders; and how the adoption of the 2030 Agenda for Sustainable Development, including the SDGs, will transform the work of HEIs. Prior research has highlighted the importance of interdisciplinary and trans-disciplinary research and studies (e.g. Mader & Rammel, 2015); and more recently Rasche et al (2017) conceive that governance systems in general can serve to make, take, or break support for the SDGs. In fact, Velazquez et al., (2005) found many obstacles preventing the success of sustainability initiatives on campuses around the world. This paper reviews progress of a sample of 300+ HEIs that are signatories to the HESI. Findings reveal a difference between HEI governance that is ‘instrumental’ and governance that is ‘holistic’ in relation to sustainability with implications for achieving the SDGs in general and for academic-business partnerships in particular. The research is supported by a grant from Enterprise Educators UK (EEUK, 2017) a network of 1,600 enterprise and entrepreneurship educators and practitioners from over 100 UK Higher and Further Education Institutions and related organisations

The entrepreneurial university as an engine for sustainable development

This study adopts a novel approach of conceptualising entrepreneurial universities through the lens of the UN higher education sustainability initiative (HESI). Transcending the narrow approach of the entrepreneurial universities as generating spin-offs, entrepreneurial universities are closely linked with the concept of sustainable development. Interpreting entrepreneurial universities as agents promoting economic, social and environmental change, the HESI can offer a useful framework for expanding the potential of entrepreneurial universities. This study reveals that whilst the majority of HESI signatories only commit to a limited number of sustainable development goals (SDGs), there is sufficient evidence of ‘best practices’ to regard the HESI as a useful and transformative framework for HEIs that can encourage innovation and entrepreneurship. To this extent, this paper aims to capture the interaction between entrepreneurial universities and the SDGs. However, the paper draws attention to the need for a holistic approach for HEIs that allows for more transdisciplinary thinking and collaboration. It is revealed that this can be challenging for HEIs. Keywords: entrepreneurial university; sustainability; higher education sustainability initiative; HESI; sustainable development goals; SDGs; entrepreneurship

Femtosecond Photoionization of Atoms under Noise

We investigate the effect of incoherent perturbations on atomic photoionization due to a femtosecond mid-infrared laser pulse by solving the time-dependent stochastic Schr\"odinger equation. For a weak laser pulse which causes almost no ionization, an addition of a Gaussian white noise to the pulse leads to a significantly enhanced ionization probability. Tuning the noise level, a stochastic resonance-like curve is observed showing the existence of an optimum noise for a given laser pulse. Besides studying the sensitivity of the obtained enhancement curve on the pulse parameters, such as the pulse duration and peak amplitude, we suggest that experimentally realizable broadband chaotic light can also be used instead of the white noise to observe similar features. The underlying enhancement mechanism is analyzed in the frequency-domain by computing a frequency-resolved atomic gain profile, as well as in the time-domain by controlling the relative delay between the action of the laser pulse and noise.Comment: 10 pages, 10 figure

A Census of Large-Scale (≥\ge 10 pc), Velocity-Coherent, Dense Filaments in the Northern Galactic Plane: Automated Identification Using Minimum Spanning Tree

Large-scale gaseous filaments with length up to the order of 100 pc are on the upper end of the filamentary hierarchy of the Galactic interstellar medium. Their association with respect to the Galactic structure and their role in Galactic star formation are of great interest from both observational and theoretical point of view. Previous "by-eye" searches, combined together, have started to uncover the Galactic distribution of large filaments, yet inherent bias and small sample size limit conclusive statistical results to be drawn. Here, we present (1) a new, automated method to identify large-scale velocity-coherent dense filaments, and (2) the first statistics and the Galactic distribution of these filaments. We use a customized minimum spanning tree algorithm to identify filaments by connecting voxels in the position-position-velocity space, using the Bolocam Galactic Plane Survey spectroscopic catalog. In the range of $7.^{\circ}5 \le l \le 194^{\circ}$, we have identified 54 large-scale filaments and derived mass ($\sim 10^3 - 10^5 \, M_\odot$), length (10-276 pc), linear mass density (54-8625 $M_\odot \, \rm{pc}^{-1}$), aspect ratio, linearity, velocity gradient, temperature, fragmentation, Galactic location and orientation angle. The filaments concentrate along major spiral arms. They are widely distributed across the Galactic disk, with 50% located within $\pm$20 pc from the Galactic mid-plane and 27% run in the center of spiral arms (aka "bones"). An order of 1% of the molecular ISM is confined in large filaments. Massive star formation is more favorable in large filaments compared to elsewhere. This is the first comprehensive catalog of large filaments useful for a quantitative comparison with spiral structures and numerical simulations.Comment: Accepted to ApJS. 20 pages (in aastex6 compact format), 6 figures, 1 table. See http://www.eso.org/~kwang/MSTpaper for (1) a preprint with full resolution Fig 6, (2) filaments catalog (Table 1) in ASCII format, and (3) a DS9 region file for the coordinates of the filament

Detection of FeO towards SgrB2

We have observed the J=5-4 ground state transition of FeO at a frequency of 153 GHz towards a selection of galactic sources. Towards the galactic center source SgrB2, we see weak absorption at approximately the velocity of other features towards this source (62 km s$^{-1}$ LSR). Towards other sources, the results were negative as they were also for MgOH(3-2) and FeC(6-5). We tentatively conclude that the absorption seen toward SgrB2 is due to FeO in the hot ($\sim$ 500 K) relatively low density absorbing gas known to be present in this line of sight. This is the first (albeit tentative) detection of FeO or any iron--containing molecule in the interstellar gas. Assuming the observed absorption to be due to FeO, we estimate [FeO]/[SiO] to be of order or less than 0.002 and [FeO]/[H$_{2}$] of order $3 10^{-11}$. This is compatible with our negative results in other sources. Our results suggest that the iron liberated from grains in the shocks associated with SgrB2 remains atomic and is not processed into molecular form.Comment: 1 postscrit figure,10 page