This Week in the Universe: January 4th – January 10th

Astrophysics and Gravitation:

Supermassive Black Hole Surprise?

CREDIT: Reines, et al., David Nidever, NRAO/AUI/NSF, NASA

The dwarf galaxy Henize 2-10, seen in visible light by the Hubble Space Telescope. The central, light-pink region shows an area of radio emission, seen with the Very Large Array. This area indicates the presence of a supermassive black hole drawing in material from its surroundings. This also is indicated by strong X-ray emission from this region detected by the Chandra X-Ray Observatory.

Astronomers have identified a supermassive black hole candidate at the centre of the dwarf galaxy Henize 2-10.  Amy Reines, one of the members of the discovery team, on why this is important:

This galaxy gives us important clues about a very early phase of galaxy evolution that has not been observed before.

For more, see Surprise: Dwarf Galaxy Harbors Supermassive Black Hole.

High Energy Physics and Particles:

Good-Bye to the Tevatron?

Obviously the big news of today is the rumour that the Tevatron will cease operations at the end of 2011.  We’re still waiting on the official announcement though.

New in Nuclear Fission

Andreyev, A., et al., (2010). New Type of Asymmetric Fission in Proton-Rich Nuclei Physical Review Letters, 105 (25) DOI: 10.1103/PhysRevLett.105.252502

An exotic fission process is studied and an exciting and anomalous asymmetry in the daughter masses is discussed.

As Abhishek Agarwal writes:

The ISOLDE team’s puzzling result hints that a very subtle interplay between macroscopic and microscopic interactions plays a deeper role in the fission process than expected and is likely to inspire detailed theoretical studies and further experiment.


For more, see Unequal Parts.

General Relativity, Quantum Gravity, et al.:

Projective flatness in the quantisation of bosons and fermions

Siye Wu (2010). Projective flatness in the quantisation of bosons and fermions arXiv arXiv: 1008.5333v2

The abstract:

We compare the quantisation of linear systems of bosons and fermions. We recall the appearance of projectively flat connection and results on parallel transport in the quantisation of bosons. We then discuss pre-quantisation and quantisation of fermions using the calculus of fermionic variables. We then define a natural connection on the bundle of Hilbert spaces and show that it is projectively flat. This identifies, up to a phase, equivalent spinor representations constructed by various polarisations. We introduce the concept of metaplectic correction for fermions and show that the bundle of corrected Hilbert spaces is naturally flat. We then show that the parallel transport in the bundle of Hilbert spaces along a geodesic is the rescaled projection or the Bogoliubov transformation provided that the geodesic lies within the complement of a cut locus. Finally, we study the bundle of Hilbert spaces when there is a symmetry.

So I’m a sucker for nice math, and this paper has got that in spades.  If you want some beautiful geometry, and some quantum mechanics (which together, I firmly believe are critical to good quantum gravity), then this is well worth the read.

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3 Responses to This Week in the Universe: January 4th – January 10th

  1. Pingback: For all who asked, next BBC series is #wonders of the Universe, finishing now, will be on in March | The America News

  2. Julie says:

    I wanted to comment about the title “language of bad physics.” For years the phrase “weigh” confused me a lot. I was told “weight” and “mass” are two very different things. Yes, of course- all scientists know that weight incorporates gravity while mass does not.

    For years it bothered me when people would say, “go weigh that on the balance.” What they really mean is, “take the mass of the object.”

    It doesn’t drive me crazy anymore but I wonder why we don’t have a term for massing something instead of “weigh.”

    Yes, its the language of bad physics (or in my case the language of bad chemistry)

  3. Pingback: This Week in the Universe: January 4th ? January 10th – PLoS Blogs (blog) at Satellite Broadband Internet