Theoretical Particle Physics and Cosmology
The theoretical particle physics and cosmology group at the Niels Bohr Institute is involved in a wide scope of research activities centered around quantum theories of gauge fields, gravity and astrophysics.
Research areas include scattering amplitudes, effective field theory, black holes, holography, lattice simulations, quantum gravity, integrability, astroparticle physics, and cosmology.
The Theoretical Particle Physics and Cosmology is a large section with a variety of research interests.
We have around 45 members, including permanent faculty, nonpermanent faculty, postdocs and PhD students. In addition we have a number of affiliate professors and emeritus professors that contribute to the section as well. We work closely with the Niels Bohr International Academy (NBIA) and the Discovery Center for particle physics.
We have two seminar series HETseminar and HETDiscovery seminar with 12 seminar per week (see these events in the Calendar). In addition we have a seminar series in Astroparticle Physics. We have periodically one or more journal clubs.
We are very focussed on teaching and supervision. We have our own 1year study track that have attracted many Danish and international master students. Moreover, a large number of master students writes a thesis with us.
The Niels Bohr institute has many M.Sc. and PhD students. The students are closely attached to the research groups and supervisor, and have many social activities for International and Danish students.
If you are interested in studying Particle Physics and Cosmology, consider looking at these pages:
 Sc. in Physics, study track in theoretical particle physics and cosmology, courses etc.
 Sc. in Physics, study track in experimental particle physics, courses etc.
 Sc. in Physics with specialization in Astrophysics, courses etc.
General information about the education, application, living in Denmark etc.
The main themes of our research are:
Theoretical particle physics:
The theoretical framework of Particle physics is Quantum Field Theory, on which we have several experts. We explore exciting new theoretical techniques in computing scattering amplitudes that aim to revolutionize our understanding of Quantum Field Theory as a framework of particle physics, and possibly replace it with an entirely new formulation. Furthermore, we use these and other methods to study the phenomenology of particle physics for use in predictions for particle accelerators.
Gravity, gravitational waves and black holes:
Classical gravity (i.e. gravity without quantum effects included) is formulated successfully by Einsteins theory of General Relativity. This theory explains fascinating physical phenomena such as black holes and gravitational waves. We study the powerful new techniques to compute gravitational waves using methods developed for particle physics scattering amplitudes. This is important for future measurements of gravitational waves. We study extensions of General Relativity (e.g. in higherdimensions, with cosmological constant, and to nonrelativistic geometries) and correspondences between gravity and fluid physics. Furthermore, regarding black holes we study theoretical aspects of astrophysical phenomena such as jetphysics and black hole shadows.
Theoretical highenergy physics:
In theoretical highenergy physics we consider the most fundamental building blocks of nature. The central goal is to unify the theory of gravity, namely General Relativity, with the theory of particle physics, i.e. Quantum Field Theory. A highly successful modern approach to this is the Holographic Principle as formulated by the AdS/CFT correspondence. This correspondence is formulated in the framework of String Theory and Mtheory. We have several experts in our section working on these topics and more. Among the fields of study are quantum gravity, the quantum nature of black holes, and integrable models.
Astroparticle physics:
Our research interests lie at the boundary between fundamental physics, astrophysics and cosmology. We focus on weakly interacting particles, such as the Neutrino, cosmic rays and gammarays. Those particles are abundantly produced in the most energetic astrophysical events, ranging from supernovas and neutronstar mergers to active galactic nuclei, as well as in the Early Universe. We aim at unveiling the nature of those particles, and at using them as probes of the inner working of a range of astrophysical sources and our Universe.
Cosmology:
Cosmology concerns the physics of the largest scales in our universe. This is closely tied to the origin of the universe and thereby also to particle and highenergy physics. In particular, we study the measurements of the Cosmic Microwave background which gives us a picture of how the universe looked shortly after its birth.
AstroNuThe Neutrino Astrophysics group at the Niels Bohr Institute aims at unveiling the nature of fascinating weakly interacting elementary particles, such as the neutrino, and at using them as probes of the engine behind the most energetic transients in our Universe. Read more >> 

Deep Space projectThe Deep Space project is based on scientific collaboration between the Niels Bohr Institute, Copenhagen University and University California (Santa Barbara), USA under supervision of Prof. P. Naselsky and Prof. P. Lubin. 

Gravity from Particle AmplitudesMeasurements of gravitational waves by the LIGO/Virgo detectors open up the exciting possibility of testing theories of gravity, including the regime of strong gravity as probed by black holes just prior to merging. 

Integrability and BeyondOur research lies within the framework of the AdS/CFT correspondence linking gauge theories and string theories. Currently, the main direction of investigation is defect conformal field theories based on maximally supersymmetric Yang Mills theory and the dual probe brane models. 

Modern approaches to scattering amplitudesRecent years have seen tremendous advances in both our understanding of quantum field theory and in our ability to make predictions for experiment. The predicted probabilities for all the possible outcomes of any experiment are encoded by functions called scattering amplitudes. 

Nonrelativistic geometry and holographyThe goal is to investigate nonrelativistic limits of gravity, string theory and holography, using recent advances in nonrelativistic geometry as an important tool in the covariant formulation of these limits. Specific topics include strong nonrelativistic gravity, string theory on torsional NewtonCartain backgrounds and limits of AdS/CFT known as Spin Matrix theory. 

Systematic Development of the SMEFT for the Study of the Higgs BosonThe Effective Field Theory research group is focused on the systematic development of the Standard Model Effective Field Theory and interpreting the data coming out of the Large Hadron collider at CERN in Run II. 

Thermodynamics of Strongly Coupled Quantum Field TheoriesThe aim of this project is to develop new theoretical methods to understand the thermodynamics of strongly coupled quantum field theories in general, and the quarkgluon plasma and its transition to ordinary matter in particular. 
Below are links to publications listed on inspirehep.net. One should keep in mind that these lists are far from complete.
 Publications 2015 >>
 Publications 2016 >>
 Publications 2017 >>
 Publications 2018 >>
 Publications 2019 >>
Instead one may check a list of recent arxiv papers by group members




Pia Lykke Kohring Section secretary Phone: +45 35325210 Email: kohring@nbi.ku.dk 
Troels Harmark Phone: +45 23 29 89 04 
Staff
Particle Physics News
External staff & students
Navn  Titel  Telefon  

Kim Splittorff  Deputy head of department  +45 24892498  split@nbi.ku.dk 
Marta Orselli  Affiliate associate professor  
Jácome Saldanha Armas  +45 35325200  jay@nbi.dk 