Laura Mersini-Houghton

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Laura Mersini-Houghton
Born Tirana, Albania
Nationality Albanian
Institutions University of North Carolina at Chapel Hill
Alma mater Tirana University
University of Maryland
University of Wisconsin–Milwaukee
Doctoral advisor Leonard Parker

Laura Mersini-Houghton (née Mersini) is a cosmologist and theoretical physicist, and associate professor at the University of North Carolina at Chapel Hill. She has developed (together with collaborators) a theory for the birth of the universe from the landscape multiverse that included five predictions proposed in 2006,[citation needed] four of which have since been observed: the CMB cold spot (2007, 2013); preferred direction associated with the quadrupole, octupole alignment (2013); CMB power suppression at low multipoles (2013); dark flow (2009); and, the deviation of the CMB amplitude (2010).[citation needed] Her theory of the origins of the universe from the landscape multiverse is not phenomenological. The theory and its predictions are derived from fundamental physics and first principles by using quantum cosmology for the wavefunction of the universe on the landscape and calculating decoherence and quantum entanglement among various surviving branches.[citation needed]

Education[edit]

Laura Mersini-Houghton received her undergraduate degree from the University of Tirana, Albania, and her M.Sc. from the University of Maryland. She was awarded a PhD in 2000 by the University of Wisconsin–Milwaukee.

After earning her PhD, Mersini-Houghton was a postdoctoral fellow at the Italian Scuola Normale Superiore di Pisa from 2000 to 2002. In 2002 she had a postdoctoral fellowship for two years at the University of Syracuse, New York. However she accepted a job as faculty at UNC in 2003. She spend most of 2003 at PI, Waterloo and in January 2004, she started as professor of theoretical physics and cosmology at the University of North Carolina Chapel Hill (UNC) with tenure in 2008.

Research[edit]

The main questions Laura Mersini-Houghton explores are[according to whom?]: Why did our universe start from such an incredibly low entropy state? Can we test the origins of the universe with our current ground and space based experiments? If cosmology is embedded in a richer structure, the multiverse, what observational evidence can test it? The motivation comes from the need for a coherent theory of the origins of the universe and a deeper understanding of nature at extreme energies. The objective is to link the current major experiments, the Planck Mission and LHC, to predictions of candidate theories. She is also interested in other fundamental topics such as the nature of space and time, (see her recent book with R.Vaas, Springer Verlag Time's Arrows[disambiguation needed], (May 2012))

Soon after the discovery of the landscape, Mersini-Houghton proposed a theory in 2004–2005 for the birth of the universe from the landscape multiverse. The main idea is based on placing the wavefunction of the universe on the landscape in order to calculate the most probable wavefunction of the universe. This theory takes into account the out of equilibrium dynamics in the initial states and it includes decoherence among the various wavefunctions. The derived probability distribution results in states of high energy inflation being the most probable initial condition to start a universe. The selection mechanism arises from the out of equilibrium evolution of gravitational versus matter degrees of freedom, as follows: gravity is a "negative heat capacity system" (vacuum energy tends to equilibrium by expanding the initial space to infinity), while matter degrees of freedom are in the class of "positive heat capacity" systems (that tend to equilibrium by collapsing the system to a point). Any realistic cosmology contains both contributions massive fluctuations, and, vacuum energy. Therefore, the evolution of the opposing tendencies of the degrees of freedom in the initial states drives the state out of equilibrium and selects only high energy initial states as "survivor" universes from the back reaction of massive fluctuations since only high energy states can grow. Initial states that contain large vacuum energies give rise to expanding physical universes. Low energy initial states cannot survive the back reaction of massive fluctuations, cannot grow and thus result in "terminal" universes.[citation needed]

In 2006 in two papers named Cosmological Avatars of the Landscape,[1] and,[2] Mersini-Houghton predicted that the CMB cold spot, which was later observed by WMAP and Planck, was "the unmistakable imprint of another universe beyond the edge of our own",.[3] Planck data has confirmed that the Cold Spot is an underdense region in the southern hemisphere, of about 200 Mpc and z~1, in perfect agreement with what she and her collaborators had predicted in their 'Cosmological Avatars of the Landscape' papers 'I: Bracketing the SUSY Breaking Scale',[1] and 'II: CMB and LSS Signatures'[2] published in 2006.

In November 2008, a NASA team led by Alexander Kashlinsky[4] observed the dark flow of galaxy clusters in the universe at exactly the velocity and alignment predicted by her[5] earlier in the 'Cosmological Avatars of the Landscape I, II' papers in 2006.[6]

In the same year (2006) WMAP reached agreement with SDSS experiment, that the overall amplitude of fluctuation is less than 1.[citation needed] If these observational findings, predicted in the 2006 papers by Mersini-Houghton et al.[citation needed] are confirmed over the next few years, then they may offer the first evidence of a universe beyond our own. Such confirmation would tie the standard model of cosmology into a more coherent picture where our universe is not at the center of the world, but part of it.[citation needed]. These predictions were just confirmed by Planck data released in March 2013.[7]

After the observational confirmation of the five predictions[citation needed] (CMB cold spot, power suppression at low l's, alignment of quadrupole with octupole, dark flow, and Sigma8~0.8) her work continues to attract international media attention, GCHEP/UNC,[8] in the New Scientist, Bild der Wissenschaft, Scientific American, and Discover magazine.

A team of astrophysicists reported between November 2008 and February 2009 that they had found evidence of the northern hemisphere CMB cold spot in analysis of WMAP data.[9] However, apart from the southern CMB cold spot, the varied statistical methods in general fail to confirm each other regarding a northern CMB cold spot.[10] Since Mersini's Theory on the Origins of the Universe from the Landscape Multiverse, several other possible causes have been suggested for the CMB cold spot. The main issue with the alternative explanations offered since Mersini's theory is that they can not produce an explanation for all observed anomalies having the same origin. Precision measurements in cosmology therefore highly constrain these phenomenological models.

Dark flow remains controversial. Its existence and velocity are "likely to stay unsettled until" the new accurate cosmic microwave background radiation data by the European Space Agency's Planck satellite are available in 2013.[11]

The Planck results for anomalies observed in the CMB were published in March 2013[7] The anomalies discovered and confirmed by Planck in the CMB are: 1. Power suppression at large distances (low I's); 2. Cold Spot; 3. Alignment of Quadrupole and Octupole in the CMB leading to a Preferred Direction; and, 4. The Overall Amplitude of Sigma_8. All of these anomalies were derived in the 2006 paper: "Why the Universe Started from a Low Entropy State",[12] well before (and independent of) any experimental detections.

Before her work on the Theory of the Origins of the Universe from the Landscape Multiverse, she investigating the problem of dark energy and developed a program with her collaborator M.Bastero-Gil, where dark energy is produced by short distance (transplanckian) modes. With other collaborators she analyzed wMAP data for the equation of state of dark energy and showed that it can be of a phantom form.

She is co-editor and author in the book 'Arrows of Time: A Debate in Cosmology',.[13]

On October 11, 2010, Laura Mersini-Houghton appeared in a BBC programme What Happened Before the Big Bang (along with Michio Kaku, Neil Turok, Andrei Linde, Roger Penrose, Lee Smolin, and other notable cosmologists and physicists) where she propounded her theory of the universe as a wave function on the landscape multiverse.[14] The programme referred to these observational tests of her theory's predictions, which makes it the only theory on the origins of our universe ever to offer predictions and have them successfully tested.[citation needed]

Laura Mersini-Houghton appeared in Morgan Freeman's 'Through the Wormhole' series in the 'Is There an Edge of the Universe' episode in 2011. This episode was nominated for an Emmy Award in 2012 in the Outstanding Science and Technology Programming category. In 2010 she also appeared in the 'Parallel Universes' episode of the National Geographic Channel: Naked Science series. Her talk in the philosophy festival in Hay-on-Wye can be found here [15]

Mersini-Houghton's work on multiverse theory is discussed in the epilogue of a recently published biography of Hugh Everett III.[16]

References[edit]

  1. ^ a b arxiv:hep-th/0611223
  2. ^ a b arxiv:hep-th/0612142
  3. ^ Marcus Chown, The void: Imprint of another universe?, New Scientist, 2007-11-24
  4. ^ A. Kashlinsky, F. Atrio-Barandela, D. Kocevski, and H. Ebeling, A measurement of large-scale peculiar velocities of clusters of galaxies: results and cosmological implications, ApJ 686 L49, doi:10.1086/592947, arXiv:0809.3734,(same paper at nasa.gov)
  5. ^ arXiv:0810.5388
  6. ^ Cosmological Avatars of the Landscape I, II; Phys. Rev. D, 77, doi:10.1103/PhysRevD.77.063510, doi:10.1103/PhysRevD.77.063511; arxiv:hep-th/0611223, arxiv:hep-th/0612142
  7. ^ a b [1]
  8. ^ GCHEP
  9. ^ arXiv:0811.2732v3/astro-ph
  10. ^ Mon. Not. R. Astron. Soc. 000, 1{13 (2009) Printed 20 May 2009 Non-Gaussian Signatures in the five-year WMAP data as identified with isotropic scaling indices G. Rossmanith1?, C. Rath1, A. J. Banday2;3 and G. Morfill1
  11. ^ Mann, Adam (2011-12-16). "Supernova research challenges cosmic "dark flow" mystery". Arstechnica.com. Retrieved 2012-11-11. 
  12. ^ [2]
  13. ^ http://www.amazon.com/The-Arrows-Time-Cosmology-Fundamental/dp/3642232582
  14. ^ "Two Programmes - Horizon, 2010-2011, What Happened Before the Big Bang?". BBC. Retrieved 2011-01-02. 
  15. ^ http://iai.tv/video/how-to-find-a-multiverse
  16. ^ "The Many Worlds of Hugh Everett III" by Peter Byrne,ISBN 978-0-19-955227-6