Fundamental Physics

A supercluster as seen by Planck via the Sunyaev-Zel'dovich effect (left) and XMM-Newton in x-rays (right).
Credits: ESA / HFI & LFI Consortia (Planck); ESA (XMM).
Click for a full-size image.

Cosmology is sensitive to a range of length and energy scales not accessible to terrestrial physics experiments and hence, if detailed observational information can accumulated, it can be used to probe fundamental processes not possible in any other way. For example, at early times in the Universe one can possibly probe GUT scale physics through its impact on the dynamics of inflation, whereas in late times one can probe infrared modifications to gravity via their influence on the expansion history of the Universe.

Within the JBCA we are interested in all possible impacts of fundamental physics on the evolution of the Universe, but a the moment we are particularly concentrating on the origins of the cosmic acceleration and the observational consequences of topological defects.

We work closely with our colleagues interested in observations, notably, those working on the Cosmic Microwave Background and Weak Gravitational Lensing to constrain our theories, and also with Prof Apostolos Pilaftsis and Dr Fedor Bezrukov in the theoretical particle physics group. [Add link to Manchester Particle Physics.

Research activities

  • Dark Energy and Modified Gravity

    The origin of the observed cosmic acceleration is presently unknown. Ideas to explain this include dark energy - a mysterious energy density component of the universe with unusual properties - or an infra-red modification to the laws of gravity. We have worked both on development of theoretical models for dark energy and modified gravity, and also developing a phenomenological prescription based on effective actions and describing a wide range of models via equations of the state for perturbations.

  • Observational consequences of topological defects

    Topological defects can form at a phase transition where spontaneous symmetry breaking takes place. If the vacuum manifold is non-trivial defects will form according to the Kibble Mechanism. Most interesting from the point of view of cosmology are cosmic strings which could form, for example, when a U(1) symmetry is broken. These strings are thought to evolve toward a self-similar scaling solution where their density remains a constant fraction of the density of the Universe. We have been particularly involved in constraining the mass per unit length of these strings using CMB and pulsar timing observations.

  • Lead researcher

    Richard Battye

    Richard Battye

    Professor of Cosmology and Associate Director (Science) in the JBCA

    Short quote relating to research.

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    An illustration of the Sunyaev-Zel'dovich Effect.

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