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  • richardmitnick 11:57 am on September 14, 2019 Permalink | Reply
    Tags: ARC Center of Excellence, , , , , , , , ,   

    From from the University of Melbourne and Australia’s ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) via COSMOS: “The hunt for a 12-billion-year-old signal” 

    From

    u-melbourne-bloc

    From University of Melbourne

    and

    arc-centers-of-excellence-bloc

    From ARC Centres of Excellence

    via

    10 September 2019
    Nick Carne

    1
    In this image the Epoch of Reionization, neutral hydrogen, in red, is gradually ionised by the first stars, shown in white.
    Paul Giel and Simon Mutch / UNIVERSITY OF MELBOURNE DARK-AGES REIONIZATION AND GALAXY OBSERVABLES FROM NUMERICAL SIMULATIONS (DRAGONS) PROGRAM

    Astronomers believe they are closing in on a signal that has been travelling across the Universe for 12 billion years.

    In a paper soon to be published in The Astrophysical Journal, an international team reports a 10-fold improvement on data gathered by the Murchison Widefield Array (MWA), a collection of 4096 dipole antennas set in the remote hinterland of Western Australia.

    SKA Murchison Widefield Array, Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO)

    The MWA was built specifically to detect electromagnetic radiation emitted by neutral hydrogen – a gas that made up most of the infant Universe in the period when the soup of disconnected protons and neutrons spawned by the Big Bang started to cool down.

    Eventually those atoms began to clump together to form the very first stars, initiating the major phase in the evolution of the Universe known as the Epoch of Reionization, or EoR.

    2
    Epoch of Reionization. Caltech/NASA

    “Defining the evolution of the EoR is extremely important for our understanding of astrophysics and cosmology,” says research leader Nichole Barry from the University of Melbourne and Australia’s ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D).

    “So far, though, no one has been able to observe it. These results take us a lot closer to that goal.”

    The neutral hydrogen that dominated space and time before and in the early period of the EoR radiated at a wavelength of approximately 21 centimetres.

    Stretched now to somewhere above two metres because of the expansion of the Universe, the signal persists – and detecting it remains the theoretical best way to probe conditions in the early days of the Cosmos.

    But that’s difficult to do, the researchers say, as the signal is old and weak and there are a lot of other galaxies in the way.

    That means the signals recorded by the MWA and other EoR-hunting devices, such as the Hydrogen Epoch of Reionisation Array (HERA) in South Africa and the Low Frequency Array (LOFAR) in The Netherlands, are extremely messy.

    UC Berkeley Hydrogen Epoch of Reionization Array (HERA), South Africa

    ASTRON LOFAR Radio Antenna Bank, Netherlands

    Using 21 hours of raw data, Barry and colleagues explored new techniques to refine analysis and exclude consistent sources of signal contamination, including ultra-faint interference generated by radio broadcasts on Earth.

    The result was a level of precision that significantly reduced the range in which the EoR may have begun, pulling in constraints by almost an order of magnitude.

    “We can’t really say that this paper gets us closer to precisely dating the start or finish of the EoR, but it does rule out some of the more extreme models,” says co-author Cathryn Trott, from Australia’s Curtin University.

    “That it happened very rapidly is now ruled out. That the conditions were very cold is now also ruled out.”

    The research was conducted by researchers from a number of institutions in Australia and New Zealand, in collaboration with Arizona State University, Brown University and MIT in the US, Kumamoto University in Japan, and Raman Research Institute in India.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    The objectives for the ARC Centres of Excellence are to:

    undertake highly innovative and potentially transformational research that aims to achieve international standing in the fields of research envisaged and leads to a significant advancement of capabilities and knowledge
    link existing Australian research strengths and build critical mass with new capacity for interdisciplinary, collaborative approaches to address the most challenging and significant research problems
    develope relationships and build new networks with major national and international centres and research programs to help strengthen research, achieve global competitiveness and gain recognition for Australian research
    build Australia’s human capacity in a range of research areas by attracting and retaining, from within Australia and abroad, researchers of high international standing as well as the most promising research students
    provide high-quality postgraduate and postdoctoral training environments for the next generation of researchers
    offer Australian researchers opportunities to work on large-scale problems over long periods of time
    establish Centres that have an impact on the wider community through interaction with higher education institutes, governments, industry and the private and non-profit sector.

    u-melbourne-campus

    The University of Melbourne (informally Melbourne University) is an Australian public research university located in Melbourne, Victoria. Founded in 1853, it is Australia’s second oldest university and the oldest in Victoria. Times Higher Education ranks Melbourne as 33rd in the world, while the Academic Ranking of World Universities places Melbourne 44th in the world (both first in Australia).

    Melbourne’s main campus is located in Parkville, an inner suburb north of the Melbourne central business district, with several other campuses located across Victoria. Melbourne is a sandstone university and a member of the Group of Eight, Universitas 21 and the Association of Pacific Rim Universities. Since 1872 various residential colleges have become affiliated with the university. There are 12 colleges located on the main campus and in nearby suburbs offering academic, sporting and cultural programs alongside accommodation for Melbourne students and faculty.

    Melbourne comprises 11 separate academic units and is associated with numerous institutes and research centres, including the Walter and Eliza Hall Institute of Medical Research, Florey Institute of Neuroscience and Mental Health, the Melbourne Institute of Applied Economic and Social Research and the Grattan Institute. Amongst Melbourne’s 15 graduate schools the Melbourne Business School, the Melbourne Law School and the Melbourne Medical School are particularly well regarded.

    Four Australian prime ministers and five governors-general have graduated from Melbourne. Nine Nobel laureates have been students or faculty, the most of any Australian university.

     
  • richardmitnick 9:16 am on August 20, 2018 Permalink | Reply
    Tags: , ARC Center of Excellence, , , , , , , ,   

    From ARC Centres of Excellence via Science Alert: “We May Soon Know How a Crucial Einstein Principle Works in The Quantum Realm” 

    arc-centers-of-excellence-bloc

    From ARC Centres of Excellence

    via

    Science Alert

    1
    (NiPlot/iStock)

    20 AUG 2018
    MICHELLE STARR

    The puzzle of how Einstein’s equivalence principle plays out in the quantum realm has vexed physicists for decades. Now two researchers may have finally figured out the key that will allow us to solve this mystery.

    Einstein’s physical theories have held up under pretty much every classical physics test thrown at them. But when you get down to the very smallest scales – the quantum realm – things start behaving a little bit oddly.

    The thing is, it’s not really clear how Einstein’s theory of general relativity and quantum mechanics work together. The laws that govern the two realms are incompatible with each other, and attempts to resolve these differences have come up short.

    But the equivalence principle – one of the cornerstones of modern physics – is an important part of general relativity. And if it can be resolved within the quantum realm, that may give us a toehold into resolving general relativity and quantum mechanics.

    The equivalence principle, in simple terms, means that gravity accelerates all objects equally, as can be observed in the famous feather and hammer experiment conducted by Apollo 15 Commander David Scott on the Moon.

    It also means that gravitational mass and inertial mass are equivalent; to put it simply, if you were in a sealed chamber, like an elevator, you would be unable to tell if the force outside the chamber was gravity or acceleration equivalent to gravity. The effect is the same.

    “Einstein’s equivalence principle contends that the total inertial and gravitational mass of any objects are equivalent, meaning all bodies fall in the same way when subject to gravity,” explained physicist Magdalena Zych of the ARC Centre of Excellence for Engineered Quantum Systems in Australia.

    “Physicists have been debating whether the principle applies to quantum particles, so to translate it to the quantum world we needed to find out how quantum particles interact with gravity.

    “We realised that to do this we had to look at the mass.”

    According to relativity, mass is held together by energy. But in quantum mechanics, that gets a bit complicated. A quantum particle can have two different energy states, with different numerical values, known as a superposition.

    And because it has a superposition of energy states, it also has a superposition of inertial masses.

    This means – theoretically, at least – that it should also have a superposition of gravitational masses. But the superposition of quantum particles isn’t accounted for by the equivalence principle.

    “We realised that we had to look how particles in such quantum states of the mass behave in order to understand how a quantum particle sees gravity in general,” Zych said.

    “Our research found that for quantum particles in quantum superpositions of different masses, the principle implies additional restrictions that are not present for classical particles – this hadn’t been discovered before.”

    This discovery allowed the team to re-formulate the equivalence principle to account for the superposition of values in a quantum particle.

    The new formulation hasn’t yet been applied experimentally; but, the researchers said, opens a door to experiments that could test the newly discovered restrictions.

    And it offers a new framework for testing the equivalence principle in the quantum realm – we can hardly wait.

    The team’s research has been published in the journal Nature Physics.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The objectives for the ARC Centres of Excellence are to:

    undertake highly innovative and potentially transformational research that aims to achieve international standing in the fields of research envisaged and leads to a significant advancement of capabilities and knowledge
    link existing Australian research strengths and build critical mass with new capacity for interdisciplinary, collaborative approaches to address the most challenging and significant research problems
    develope relationships and build new networks with major national and international centres and research programs to help strengthen research, achieve global competitiveness and gain recognition for Australian research
    build Australia’s human capacity in a range of research areas by attracting and retaining, from within Australia and abroad, researchers of high international standing as well as the most promising research students
    provide high-quality postgraduate and postdoctoral training environments for the next generation of researchers
    offer Australian researchers opportunities to work on large-scale problems over long periods of time
    establish Centres that have an impact on the wider community through interaction with higher education institutes, governments, industry and the private and non-profit sector.

     
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