October 11, 2023
Niels Bohr Institute
Europe/Copenhagen timezone

Research

THEORETICAL HIGH-ENERGY PHYSICS
The idea of particles and strings being related by holography has led to amazing new insights in many different fields ranging from black hole physics and quantum gravity to CERN experiments and the strong coupling behavior of condensed matter systems. In theoretical high-energy physics we study all of these topics. In particular, we develop new mathematical tools for scattering amplitudes, we investigate extensions and non-relativistic limits of general relativity and holography, and we develop exact methods to solve conformal field theories with boundaries.

GRAVITATIONAL PHYSICS
Measurements of gravitational waves by LIGO/Virgo and forthcoming detectors deliver compelling opportunities for testing theories of fundamental physics, including the regime of strong gravity as probed by black holes just before merging. To this end, it helps to use ideas and methods from quantum field theory and scattering amplitudes to produce new theoretical precision. Other queries are more phenomenological. Are black holes the simplest possible macroscopic objects? Do event horizons exist? Can gravitational waves convey information about inaccessible dark matter in the Universe?

THEORETICAL ASTROPHYSICS
This line of research at the NBIA spans a variety of topics, using a broad range of theoretical techniques and numerical tools. Topics of interest include accretion flows around young stars and compact objects, the formation of black hole binary systems and subsequent mergers, the interstellar medium, the intergalactic medium in galaxy clusters, and the early evolution of our solar system and exoplanetary systems. We have access to powerful computer resources and interact on a daily basis with the Computational Astrophysics Group at the NBI.

BIOPHYSICS & ACTIVE MATTER
The NBIA has recently launched an exciting new initiative to expand into soft matter physics and the hot topic of active, self-organizing matter: bacterial colonies, cellular tissues, or filaments inside living cells. A distinctive feature of these active materials is their ability to autonomously create coherent flows with the entire material moving as a unit. Such coherent flows of cells occur in vital biological processes—from wound healing and organ formation to bacterial invasion and tumor progression—and are the subject of intense studies due to their potential for medical intervention.

PARTICLE ASTROPHYSICS
Research in this field lies at the rich interface between astrophysics, cosmology, and fundamental physics. We are particularly interested in exploring the Universe through cosmic rays, photons, neutrinos, and gravitational waves. A strong focus at NBIA lies on neutrino astrophysics. We study the role of neutrinos in powering sources, their use as powerful probes of hidden source interiors, and seek to unveil the fundamental properties of neutrinos from studying their interactions in dense environments and on cosmic backgrounds, and from their detection in neutrino telescopes.

CONDENSED MATTER THEORY
The condensed matter theory group at the NBIA seeks to understand how to create, control, measure, and protect quantum coherence and entanglement in quantum many-body systems.  This is crucial for building large controlled interacting quantum devices, such as solid-state qubits, nanowires and nanotubes.  We maintain close links with the Center for Quantum Devices, with many opportunities for theory-experiment collaborations on these fundamental topics.