Dr Konstantinos Dimopoulos

Dr Konstantinos Dimopoulos

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C39 Physics Building
Lancaster University
Bailrigg
Lancaster
United Kingdom
LA1 4YB

+44 (0)1524 593645

Research Interests

Particle Cosmology

My research area is Particle Cosmology. Cosmology is the study of the Universe as a system. Modern Cosmology is based on the Hot Big Bang (HBB) model, which provides a successful description of the Universe history as far back as the first second of its existence. However, the HBB leaves many questions unanswered. The answers hide in the elusive primordial era, when the Universe was so dense and hot that its evolution was determined by High Energy Physics phenomena. In fact, since the energy scale of the cosmology in the Early Universe is much higher than the scale of electroweak unification, one needs to employ Physics beyond the Standard Model to investigate the remaining mysteries. Particle Cosmology uses what is known or conjectured about the fundamental interactions in the context of Particle Theory for the study of the Early Universe.

Cosmic Inflation

One of my main areas of research is Cosmic Inflation. This can be defined as a period of accelerated expansion of space in the Early Universe. Inflation is a compelling solution to the problems of the HBB that have to do with why the Universe appears to be so big and so uniform on very large scales. It also provides an elegant way to generate the small perturbations in the density of the Universe, which are necessary for the formation of structures such as galaxies and galactic clusters. The existence and the characteristics of these Primordial Density Perturbations (PDP) have been observationally determined because they reflect themselves on the Cosmic Microwave Background Radiation (CMBR) by generating anisotropies and polarisation.

My research regarding Inflation aims to construct and study the dynamics of realistic inflationary models based on Particle Theory. I am also interested in the generation of the PDP during Inflation, which can be explored by investigating the behaviour and evolution of suitable fields, belonging to simple extensions of the Standard Model. These fields may or may not be related to inflationary expansion itself (if not they are called Curvatons). At this level there is also considerable interface between cosmology and String Theory, Branes and Large Extra Dimensions. It should be noted that recent, precise CMBR observations from the WMAP satellite, have confirmed the basic predictions of Inflation. Hence, Cosmic Inflation is now considered a necessary extension of HBB cosmology.

Quintessenctial Inflation

Another open issue for cosmologists today is the recent observation that the Universe seems to be engaging into an era of accelerated expansion at present. This is attributed to a mysterious Dark Energy substance, whose nature and origin is unknown. The simplest choice of Dark Energy is a Cosmological Constant. However, such a constant has to be incredibly fine-tunned (by hundreds of orders of magnitude) to explain the observations. Alternatively, it has been suggested that the Universe is undergoing a late period of inflation, driven by a scalar field called Quintessence; the fifth element after Dark Matter, neutrinos, photons and baryons. In my research I concentrate on the possibility that the field that drives Cosmic Inflation in the Early Universe is the same with Quintessence. The study of such Quintessential Inflation is not only economical but has the advantage of using a single theoretical framework to determine the global evolution of the Universe from extremely early times until the present.

Primordial Magnetic Fields

Another area of my research is the possible generation of large-scale Primordial Magnetic Fields (PMFs) in the Early Universe. Such fields can be responsible for the observed intergalactic magnetic fields as well as the magnetic fields of the galaxies themselves. One can generate PMFs only in out-of thermal equilibrium conditions, because they break isotropy. Such opportunities exist during Phase Transitions in the Early Universe (at the breaking of symmetries of the fundamental interactions) and during Cosmic Inflation (when the Universe is supercooled because any preexisting entropy is inflated away).

Cosmic Vector Fields

Finally, in recent years I have pioneered the study of the effects of vector boson fields (such as the photon, i.e. the quantum of the electromagnetic field) on the PDP and CMBR. Such fields are produced in a similar manner as PMFs during Cosmic Inflation. I have shown that, under certain circumstances, vector boson fields can contribute significantly or even be solely responsible for the generation of the PDP. In contrast to scalar fields to which the PDP was attributed until now, vector boson fields have been observed in CERN (e.g. the W and Z massive gauge bosons). Moreover, they can give rise to distinct observational signatures on the CMBR, namely statistical anisotropy. This amounts to direction dependent patterns, which select a preferred direction on the microwave sky. Indeed, in recent years there is tantalising observational evidence that such a preferred direction may exist (manifested as alignment of the low multipoles of CMBR). Beyond the CMBR, statistical anisotropy may also reflect itself in the distribution of cosmic structures (e.g. rows of galaxies). Statistical anisotropy may well be observed in the near future by the Planck satellite, which was launched by ESA in May 2009. If so then one would have to involve vector boson fields in model-building inflation and in the generation of the PDP. This is the aim of my research. Theories beyond the Standard Model include many suitable candidates for cosmic vector fields such as the supermassive gauge bosons in Grand Unified Theories or fluxes in the extra dimensions needed for their stabilisation in String Theory.

 

Konstantinos Dimopoulos's Publications

2014

Non-bunch-Davis initial state reconciles chaotic models with BICEP and Planck

Ashoorioon, A., Dimopoulos, K., M. Sheikh-Jabbari, M. & Shiu, G. 24/03/2014 In : Cornell University Library, arXiv.

Research output: Contribution to journalJournal article

Reconciliation of high energy scale models of inflation with Planck

Ashoorioon, A., Dimopoulos, K., M. Sheikh-Jabbari, M. & Shiu, G. 14/02/2014 In : Journal of Cosmology and Astroparticle Physics. 2014, 2, 12 p.025

Research output: Contribution to journalJournal article

Inflationary buildup of a vector field condensate and its cosmological consequences

Bueno Sanchez, J. & Dimopoulos, K. 10/01/2014 In : Journal of Cosmology and Astroparticle Physics. 2014, 1, 32 p.012

Research output: Contribution to journalJournal article

2013

D-branes and cosmic structure

Wills, D., Dimopoulos, K. & Zavala, I. 07/2013 Proceedings of the Barcelona Postgrad Encounters in Fundamental Physics. Fernandez, D., Frob, M. B., Letella, I. & Dektor, A. (eds.). Spain: Daniel Fernandez Moreno, p. 179-190 12 p.

Research output: Contribution in Book/Report/ProceedingsPaper

Statistical Anisotropy from Vector Curvaton in D-brane Inflation

Dimopoulos, K., Wills, D. & Zavala, I. 1/03/2013 In : Nuclear Physics B. 868, 1, p. 120-155 36 p.

Research output: Contribution to journalJournal article

Correlated curvature perturbations and magnetogenesis from the GUT gauge bosons

Dimopoulos, K. 02/2013 In : Astroparticle Physics. 42, p. 86-89 4 p.

Research output: Contribution to journalJournal article

2012

The hybrid curvaton

Dimopoulos, K., Kohri, K. & Matsuda, T. 26/06/2012 In : Physical Review D. 85, 12, 7 p.123541

Research output: Contribution to journalJournal article

Parity Violating Statistical Anisotropy

Dimopoulos, K. & Karciauskas, M. 6/06/2012 In : Journal of High Energy Physics. 2012, 6, 35 p.JHEP06(2012)040

Research output: Contribution to journalJournal article

The inflating curvaton

Dimopoulos, K., Kohri, K., Lyth, D. & Matsuda, T. 12/03/2012 In : Journal of Cosmology and Astroparticle Physics. 03, p. 0-8 9 p.JCAP03(2012)022

Research output: Contribution to journalJournal article

Statistical Anisotropy and the Vector Curvaton Paradigm

Dimopoulos, K. 5/03/2012 In : International Journal of Modern Physics D. 21, 3, p. 1-26 26 p.1250023

Research output: Contribution to journalJournal article

Eliminating the eta-problem in SUGRA hybrid inflation with vector backreaction

Dimopoulos, K., Lazarides, G. & Wagstaff, J. 15/02/2012 In : Journal of Cosmology and Astroparticle Physics. 02, p. 0-26 27 p.JCAP02(2012)018

Research output: Contribution to journalJournal article

2011

The gravitino problem in supersymmetric warm inflation

Bueno Sanchez, J. C., Bastero Gil, M., Berera, A., Dimopoulos, K. & Kohri, K. 9/03/2011 In : Journal of Cosmology and Astroparticle Physics. 2011, 3, 020

Research output: Contribution to journalJournal article

Particle Production of Vector Fields: Scale Invariance is Attractive

Wagstaff, J. & Dimopoulos, K. 25/01/2011 In : Physical Review D. 83, 2, 33 p.023523

Research output: Contribution to journalJournal article

The quantum origin of cosmic structure: theory and observations

Dimopoulos, K. 2011 In : Journal of Physics: Conference Series. 283, 1, 22 p.012010

Research output: Contribution to journalJournal article

2010

Vector curvaton with varying kinetic function.

Dimopoulos, K., Karciauskas, M. & Wagstaff, J. M. 29/01/2010 In : Physical Review. 81, 2, p. 023522

Research output: Contribution to journalJournal article

Vector curvaton without instabilities.

Dimopoulos, K., Karciauskas, M. & Wagstaff, J. M. 25/01/2010 In : Physics Letters B. 683, 4-5, p. 298-301 4 p.

Research output: Contribution to journalJournal article

2009

Where galaxies really come from.

Dimopoulos, K. 1/11/2009 In : Contemporary Physics. 50, 6, p. 633-646 14 p.

Research output: Contribution to journalJournal article

Anisotropic non-Gaussianity from vector field perturbations.

Karciauskas, M., Dimopoulos, K. & Lyth, D. H. 15/07/2009 In : Physical Review. 80, 2, p. 023509

Research output: Contribution to journalJournal article

Statistical anisotropy of the curvature perturbation from vector field perturbations.

Dimopoulos, K., Karciauskas, M., Lyth, D. H. & Rodriguez, Y. 26/05/2009 In : Journal of Cosmology and Astroparticle Physics. 2009, 5, p. 013

Research output: Contribution to journalJournal article

2008

Non-minimally coupled vector curvaton.

Dimopoulos, K. & Karciauskas, M. 29/07/2008 In : Journal of High Energy Physics. 2008, 07, 10 p.119

Research output: Contribution to journalJournal article

Warm hilltop inflation.

Bueno-Sanchez, J. C., Bastero Gil, M., Berera, A. & Dimopoulos, K. 15/06/2008 In : Physical Review. 77, 12, p. 123527

Research output: Contribution to journalJournal article

2007

Density Perturbations in the Universe from Massive Vector Fields.

Dimopoulos, K. 20/11/2007 In : American Institute of Physics Conference Proceedings. 957, 1, p. 387-390 4 p.

Research output: Contribution to journalJournal article

Curvaton reheating allows a TeV Hubble scale in non-oscillatory inflation.

Bueno-Sanchez, J. C. & Dimopoulos, K. 9/11/2007 In : Journal of Cosmology and Astroparticle Physics. 2007, 11, p. 007

Research output: Contribution to journalJournal article

Trapped quintessential inflation in the context of flux compactifications.

Bueno-Sanchez, J. C. & Dimopoulos, K. 4/10/2007 In : Journal of Cosmology and Astroparticle Physics. 2007, 10, p. 002

Research output: Contribution to journalJournal article

Supergravity inspired Vector Curvaton.

Dimopoulos, K. 14/09/2007 In : Physical Review. 76, 6197, p. 063506

Research output: Contribution to journalJournal article

A-term inflation and the minimal supersymmetric standard model.

Bueno-Sanchez, J. C., Dimopoulos, K. & Lyth, D. H. 16/01/2007 In : Journal of Cosmology and Astroparticle Physics. 2007, 1, p. 015

Research output: Contribution to journalJournal article

Trapped Quintessential Inflation from Flux Compactifications.

Dimopoulos, K. 2007 IDM 2006: 6th International Workshop On The Identification Of Dark Matter. Axenides, M., Fanourakis, G. & Vergados, J. (eds.). World Scientific, p. 635-646 12 p.

Research output: Contribution in Book/Report/ProceedingsChapter

2006

Trapped Quintessential Inflation.

Bueno-Sanchez, J. C. & Dimopoulos, K. 16/11/2006 In : Physics Letters B. 642, 4, p. 294-301 8 p.

Research output: Contribution to journalJournal article

Can a vector field be responsible for the curvature perturbation in the Universe?

Dimopoulos, K. 2/10/2006 In : Physical Review. 74, 8, p. 083502

Research output: Contribution to journalJournal article

Inflation at the TeV scale with a PNGB curvaton.

Dimopoulos, K. 16/03/2006 In : Physics Letters B. 634, 4, p. 331-339 9 p.

Research output: Contribution to journalJournal article

Modular inflation and the orthogonal axion as curvaton.

Dimopoulos, K. & Lazarides, G. 15/01/2006 In : Physical Review. 73, 2, p. 023525

Research output: Contribution to journalJournal article

2005

The Density Perturbation in the Universe: Beyond the Inflaton Paradigm.

Axenides, M., Dimopoulos, K. & Kehagias, A. 11/2005 In : Nuclear Physics B - Proceedings Supplements. 148

Research output: Contribution to journalJournal article

Cosmic superstrings and primordial magnetogenesis.

Davis, A-C. & Dimopoulos, K. 15/08/2005 In : Physical Review D. 72, 4, p. 043517

Research output: Contribution to journalJournal article

Hybrid inflation without flat directions and without primordial black holes.

Dimopoulos, K. & Axenides, M. 17/06/2005 In : Journal of Cosmology and Astroparticle Physics. 2005, 06, p. 008

Research output: Contribution to journalJournal article

Low scale inflation and the curvaton mechanism.

Dimopoulos, K., Lyth, D. H. & Rodriguez Garcia, Y. 11/03/2005 In : Journal of High Energy Physics. 2005, 02, p. 055

Research output: Contribution to journalJournal article

2004

Curvaton and QCD axion in supersymmetric theories.

Chun, E. J., Dimopoulos, K. & Lyth, D. H. 15/11/2004 In : Physical Review. 70, 10, p. 103510

Research output: Contribution to journalJournal article

Hybrid dark sector: Locked quintessence and dark matter.

Axenides, M. & Dimopoulos, K. 19/07/2004 In : Journal of Cosmology and Astroparticle Physics. 2004, 07, p. 010

Research output: Contribution to journalJournal article

Models of inflation liberated by the curvaton hypothesis.

Dimopoulos, K. & Lyth, D. H. 15/06/2004 In : Physical Review. 69, 12, p. 123509

Research output: Contribution to journalJournal article

Modular hybrid inflation without flat directions and the curvaton.

Dimopoulos, K. 2004 39th Rencontres De Moriond Workshop On Exploring The Universe: Contents And Structures Of The Universe. Martin, J. (ed.).

Research output: Contribution in Book/Report/ProceedingsChapter

2003

Curvaton dynamics.

Dimopoulos, K., Lazarides, G., Lyth, D. H. & Ruiz de Austri, R. 15/12/2003 In : Physical Review. 68, 12, p. 123515

Research output: Contribution to journalJournal article

Curvaton hypothesis and the eta-problem of quintessential inflation, with and without branes.

Dimopoulos, K. 15/12/2003 In : Physical Review. 68, 12, p. 123506

Research output: Contribution to journalJournal article

The Curvaton as a pseudoNambu-Goldstone boson.

Dimopoulos, K., Lyth, D. H., Notari, A. & Riotto, A. 28/10/2003 In : Journal of High Energy Physics. 2003, 07, p. 053

Research output: Contribution to journalJournal article

The Peccei-Quinn field as curvaton.

Dimopoulos, K., Lazarides, G., Lyth, D. H. & Ruiz de Austri, R. 25/05/2003 In : Journal of High Energy Physics. 2003, 05, p. 057

Research output: Contribution to journalJournal article

2002

Modeling quintessential inflation.

Dimopoulos, K. & Valle, J. W. F. 12/2002 In : Astroparticle Physics. 18, 3, p. 287-306 20 p.

Research output: Contribution to journalJournal article

Natural magnetogenesis from inflation.

Dimopoulos, K., Prokopec, T., Tornkvist, O. & Davis, A-C. 22/02/2002 In : Physical Review. 65, 6, p. 063505

Research output: Contribution to journalJournal article

Galactic magnetic fields as a consequence of inflation.

Dimopoulos, K. 2002 2nd Hellenic Cosmology Conference. Kotsakis, S. & Plionis, M. (eds.).

Research output: Contribution in Book/Report/ProceedingsChapter

Modeling quintessential inflation with branes.

Dimopoulos, K. 2002 18th IAP Colloquium On The Nature Of Dark Energy: Observational And Theoretical Results On The Accelerating Universe. Brax, P., Martin, J. & Uzan, J-P. (eds.). p. 275-278 4 p.

Research output: Contribution in Book/Report/ProceedingsChapter

2001

Towards a model of quintessential inflation.

Dimopoulos, K. 04/2001 In : Nuclear Physics B - Proceedings Supplements. 95, 1-3, p. 70-73 4 p.

Research output: Contribution to journalJournal article

Primordial spectrum of gauge fields from inflation.

Davis, A-C., Dimopoulos, K., Prokopec, T. & Tornkvist, O. 8/03/2001 In : Physics Letters B. 501, 3-4, p. 165-172 8 p.

Research output: Contribution to journalJournal article

Models of quintessential inflation.

Dimopoulos, K. 2001 International Workshop On Particle Physics And The Early Universe (COSMO-01). Enqvist, K. (ed.).

Research output: Contribution in Book/Report/ProceedingsChapter

2000

Large scale primordial magnetic fields from inflation and preheating

Tornkvist, O., Davis, A-C., Dimopoulos, K. & Prokopec, T. 2000 COSMOLOGY AND PARTICLE PHYSICS: CAPP 2000: Proceedings. Durrer, R., Garcia- Bellido, J. & Shaposhnikov, M. (eds.). Melville, N.Y.: American Institute of Physics, p. 443-446 4 p.

Research output: Contribution in Book/Report/ProceedingsChapter

1999

Cosmological consequences of superconducting string networks.

Dimopoulos, K. & Davis, A-C. 28/01/1999 In : Physics Letters B. 446, 3-4, p. 238-246 9 p.

Research output: Contribution to journalJournal article

1998

Primordial magnetic fields from superconducting cosmic strings.

Dimopoulos, K. 15/04/1998 In : Physical Review. 57, 8, p. 4629-4641 13 p.

Research output: Contribution to journalJournal article

Friction domination with superconducting strings.

Dimopoulos, K. & Davis, A-C. 15/01/1998 In : Physical Review. 57, 2, p. 692-701 10 p.

Research output: Contribution to journalJournal article

Generating primordial magnetic fields from superconducting cosmic strings.

Dimopoulos, K. 1998 COSMO 97: 1st International Workshop on Particle Physics and the Early Universe. World Scientific, p. 411-413 3 p.

Research output: Contribution in Book/Report/ProceedingsChapter

1997

Primordial magnetic fields in false vacuum inflation.

Davis, A-C. & Dimopoulos, K. 15/06/1997 In : Physical Review. 55, 12, p. 7398-7414 17 p.

Research output: Contribution to journalJournal article

Evolution of primordial magnetic fields.

Dimopoulos, K. & Davis, A-C. 2/01/1997 In : Physics Letters B. 390, 1-4, p. 87-96 10 p.

Research output: Contribution to journalJournal article