The CMB temperature trispectrum of cosmic strings (2009)
Hindmarsh, Mark, Ringeval, Christophe, Suyama, Teruaki
We provide an analytical expression for the trispectrum of the Cosmic Microwave Background (CMB) temperature anisotropies induced by cosmic strings. Our result is derived for the small angular scales...
The CMB temperature bispectrum induced by cosmic strings (2009)
Hindmarsh, Mark, Ringeval, Christophe, Suyama, Teruaki
The Cosmic Microwave Background (CMB) bispectrum of the temperature anisotropies induced by a network of cosmic strings is derived for small angular scales, under the assumption that the principal...
Abelian Higgs Cosmic Strings: Small Scale Structure and Loops (2008)
Hindmarsh, Mark, Stuckey, Stephanie, Bevis, Neil
Classical lattice simulations of the Abelian Higgs model are used to investigate small scale structure and loop distributions in cosmic string networks. Use of the field theory ensures that the...
Urrestilla, Jon, Mukherjee, Pia, Liddle, Andrew R., Bevis, Neil, Hindmarsh, Mark, Kunz, Martin
While observations indicate that the predominant source of cosmic inhomogeneities are adiabatic perturbations, there are a variety of candidates to provide auxiliary trace effects, including...
Large Radius Hagedorn Regime in String Gas Cosmology (2007)
Skliros, Dimitri, Hindmarsh, Mark
We calculate the equation of state of a gas of strings at high density in a large toroidal universe, and use it to determine the cosmological evolution of background metric and dilaton fields in the...
Oscillons and Domain Walls (2007)
Oscillons, extremely long-lived localized oscillations of a scalar field, are shown to be produced by evolving domain wall networks in quartic theory in two spatial dimensions. We study the oscillons...
Semiclassical decay of topological defects (2007)
Borsanyi, Szabolcs, Hindmarsh, Mark
Perturbative estimates suggest that extended topological defects such as cosmic strings emit few particles, but numerical simulations of the fields from which they are constructed suggest the...
Cosmic microwave anisotropies from BPS semilocal strings (2007)
Urrestilla, Jon, Bevis, Neil, Hindmarsh, Mark, Kunz, Martin, Liddle, Andrew R.
We present the first ever calculation of cosmic microwave background CMB anisotropy power spectra from semilocal cosmic strings, obtained via simulations of a classical field theory. Semilocal...
Perturbations and moduli space dynamics of tachyon kinks (2007)
The dynamic process of unstable D-branes decaying into stable ones with one dimension lower can be described by a tachyon field with a Dirac-Born-Infeld effective action. In this paper we investigate...
Cosmology with Twisted Tori (2007)
Karthauser, Josef L. P., Saffin, P. M., Hindmarsh, Mark
We consider the cosmological role of the scalar fields generated by the compactification of 11-dimensional Einstein gravity on a 7D elliptic twisted torus, which has the attractive features of giving...
Unsuccessful cosmology with Modified Gravity Models (2007)
De Felice, Antonio, Hindmarsh, Mark
A class of Modified Gravity Models, consisting of inverse powers of linear combination of quadratic curvature invariants, is studied in the full parameter space. We find that singularity-free...
CMB polarization power spectra contributions from a network of cosmic strings (2007)
Bevis, Neil, Hindmarsh, Mark, Kunz, Martin, Urrestilla, Jon
We present the first calculation of the possible (local) cosmic string contribution to the cosmic microwave background polarization spectra from simulations of a string network (rather than a...
Fitting CMB data with cosmic strings and inflation (2007)
Bevis, Neil, Hindmarsh, Mark, Kunz, Martin, Urrestilla, Jon
We perform a multiparameter likelihood analysis to compare measurements of the cosmic microwave background (CMB) power spectra with predictions from models involving cosmic strings. Adding strings to...
Simulations of Cold Electroweak Baryogenesis: Finite time quenches (2006)
Tranberg, Anders, Smit, Jan, Hindmarsh, Mark
The electroweak symmetry breaking transition may supply the appropriate out-of-equilibrium conditions for baryogenesis if it is triggered sufficiently fast. This can happen at the end of low-scale...
Simulations of Cold Electroweak Baryogenesis (2006)
Tranberg, Anders, Smit, Jan, Hindmarsh, Mark
We present real-time lattice simulations of Cold Electroweak Baryogenesis, in which the baryon asymmetry of the Universe is generated during tachyonic electroweak symmetry breaking at the end of...
Numerical Investigations of Oscillons in 2 Dimensions (2006)
Oscillons, extremely long-living localized oscillations of a scalar field, are studied in theories with quartic and sine-Gordon potentials in two spatial dimensions. We present qualitative results...
Scaling in a SU(2)/Z_3 model of cosmic superstring networks (2006)
Hindmarsh, Mark, Saffin, P. M.
Motivated by recent developments in superstring theory in the cosmological context, we examine a field theory which contains string networks with 3-way junctions. We perform numerical simulations of...
Bevis, Neil, Hindmarsh, Mark, Kunz, Martin, Urrestilla, Jon
We present the first field-theoretic calculations of the contribution made by cosmic strings to the temperature power spectrum of the cosmic microwave background (CMB). Unlike previous work, in which...
Ghosts, Instabilities, and Superluminal Propagation in Modified Gravity Models (2006)
De Felice, Antonio, Hindmarsh, Mark, Trodden, Mark
We consider Modified Gravity models involving inverse powers of fourth-order curvature invariants. Using these models' equivalence to the theory of a scalar field coupled to a linear combination of...
WIMP Dark Matter and the QCD Equation of State (2005)
Hindmarsh, Mark, Philipsen, Owe
Weakly Interacting Massive Particles (WIMPs) of mass m freeze out at a temperature T_f ~ m/25, i.e. in the range 400 MeV -- 40 GeV for a particle in the typical mass range 10 -- 1000 GeV. The WIMP...
WMAP constraints on inflationary models with global defects (2004)
Bevis, Neil, Hindmarsh, Mark, Kunz, Martin
We use the cosmic microwave background angular power spectra to place upper limits on the degree to which global defects may have aided cosmic structure formation. We explore this under the...
Kink-boundary collisions in a two dimensional scalar field theory (2003)
Antunes, Nuno D., Copeland, Edmund J., Hindmarsh, Mark, Lukas, Andre
In a two-dimensional toy model, motivated from five-dimensional heterotic M-theory, we study the collision of scalar field kinks with boundaries. By numerical simulation of the full two-dimensional...
Decay of Magnetic Fields in the Early Universe (2003)
Hindmarsh, Mark, Christensson, M., Brandenburg, A.
We study the evolution of a stochastic helical magnetic field generated in the early Universe after the electroweak phase transition, using standard magnetohydrodynamics (MHD). We find how the...
Scaling in Numerical Simulations of Domain Walls (2002)
Garagounis, Theodore, Hindmarsh, Mark
We study the evolution of domain wall networks appearing after phase transitions in the early Universe. They exhibit interesting dynamical scaling behaviour which is not yet well understood, and are...
Scaling laws in decaying helical hydromagnetic turbulence (2002)
Christensson, Mattias, Hindmarsh, Mark, Brandenburg, Axel
We study the evolution of growth and decay laws for the magnetic field coherence length xi, energy E_M and magnetic helicity H in freely decaying 3D MHD turbulence. We show that with certain...
Antunes, Nuno D., Copeland, Edmund J., Hindmarsh, Mark, Lukas, Andre
We present a toy model for five-dimensional heterotic M-theory where bulk three-branes, originating in 11 dimensions from M five-branes, are modelled as kink solutions of a bulk scalar field theory....
Level Set Method for the Evolution of Defect and Brane Networks (2002)
A theory for studying the dynamic scaling properties of branes and relativistic topological defect networks is presented. The theory, based on a relativistic version of the level set method,...
MHD inverse cascade in the early Universe (2002)
Hindmarsh, Mark, Christensson, M., Brandenburg, A.
We have carried out numerical simulations of freely decaying magnetohydrodynamic (MHD) turbulence in three dimensions, which can be applied to the evolution of stochastic magnetic fields in the early...
Sphalerons in Two Higgs Doublet Theories (2001)
Grant, Jackie, Hindmarsh, Mark
We undertake a comprehensive investigation of the properties of the sphaleron in electroweak theories with two Higgs doublets. We do this in as model-independent a way as possible: by exploring the...
Sphalerons with Two Higgs Doublets (2001)
Hindmarsh, Mark, Grant, Jackie
We report on work studying the properties of the sphaleron in models of the electroweak interactions with two Higgs doublets in as model-independent a way as possible: by exploring the physical...
Inverse cascade in decaying 3D magnetohydrodynamic turbulence (2000)
Christensson, Mattias, Hindmarsh, Mark, Brandenburg, Axel
We perform direct numerical simulations of three-dimensional freely decaying magnetohydrodynamic (MHD) turbulence. For helical magnetic fields an inverse cascade effect is observed in which power is...
Magnetic fields in the early universe in the string approach to MHD (1999)
Christensson, Mattias, Hindmarsh, Mark
There is a reformulation of magnetohydrodynamics in which the fundamental dynamical quantities are the positions and velocities of the lines of magnetic flux in the plasma, which turn out to obey...
Structure formation with strings plus inflation: a new paradigm (1999)
Magueijo, Joao, Contaldi, Carlo, Hindmarsh, Mark
Recent developments in inflation model building, based on supersymmetry, have produced compelling models in which strings are produced at the end of inflation. In such models the cosmological...
Sphalerons with CP-Violating Higgs Potentials (1998)
Grant, Jackie, Hindmarsh, Mark
We investigate the effect on the sphaleron in the two Higgs doublet electroweak theory of including CP violation in the Higgs potential. To have better control over the relation between the sphaleron...
CMB and LSS Power Spectra From Local Cosmic String Seeded Struture Formation (1998)
Contaldi, Carlo R., Hindmarsh, Mark, Magueijo, Joao
We evaluate the two point functions of the stress energy from the largest string simulations carried out so far. The two point functions are used to calculate the cosmic microwave background (CMB)...
CMB and density fluctuations from strings plus inflation (1998)
Contaldi, Carlo, Hindmarsh, Mark, Magueijo, Joao
In cosmological models where local cosmic strings are formed at the end of a period of inflation, the perturbations are seeded both by the defects and by the quantum fluctuations. In a subset of...
The power spectra of CMB and density fluctuations seeded by local cosmic strings (1998)
Contaldi, Carlo, Hindmarsh, Mark, Magueijo, Joao
We compute the power spectra in the cosmic microwave background and cold dark matter (CDM) fluctuations seeded by strings, using the largest string simulations performed so far to evaluate the...
Constraints on Axion Models (1998)
Hindmarsh, Mark, Moulatsiotis, Photis
Two particular classes of axion models are presented, each one yielding a lower bound on the axion decay constant, based though on different considerations. In the first class only some, and not all,...
Constraints on Axion Models from $K^+\to\pi^+ a$ (1998)
Hindmarsh, Mark, Moulatsiotis, Photis
We explore a new class of axion models in which some, but not all, of the left-handed quarks have a Peccei-Quinn symmetry. These models are potentially afflicted by flavour changing neutral currents....
Cosmic Strings - Dead Again? (1998)
I report on recent numerical simulations of the simplest field theory with cosmic string solutions, the Abelian Higgs model. We find that random networks of string quickly converge to a scaling...
Ordering Dynamics of Topological Defect Networks (1997)
I report on some work in progress on the dynamics of extended objects in field theories after a rapid phase transition, as is relevant in the early Universe. An analytic technique, originally...
Numerical simulations of string networks in the Abelian-Higgs model (1997)
Vincent, Graham, Antunes, Nuno D., Hindmarsh, Mark
We present the results of a field theory simulation of networks of strings in the Abelian Higgs model. Starting from a random initial configuration we show that the resulting vortex tangle approaches...
Instability of the one-texture universe (1997)
Chen, Xuelei, Hindmarsh, Mark, Kamionkowski, Marc, Liddle, Andrew R.
The one-texture universe, introduced by Davis in 1987, is a homogeneous mapping of a scalar field with an S^3 vacuum into a closed universe. It has long been known to mathematicians that such...
Constraints on Variant Axion Models (1997)
Hindmarsh, Mark, Moulatsiotis, Photis
A particular class of variant axion models with two higgs doublets and a singlet is studied. In these models the axion couples either to the $u$-quark or $t$-quark or both, but not to $b$, $c$, $s$,...
The Thermodynamics of Cosmic String densities in U(1) Scalar Field Theory (1997)
Antunes, Nuno D., Bettencourt, Luis M. A., Hindmarsh, Mark
We present a full characterization of the phase transition in U(1) scalar field theory and of the associated vortex string thermodynamics in 3D. We show that phase transitions in the string densities...
Magnetic Fields from Phase Transitions (1997)
Hindmarsh, Mark, Everett, Allen
The generation of primordial magnetic fields from cosmological phase transitions is discussed, paying particular attention to the electroweak transition and to the various definitions of the...
On the instability of the one-texture universe (1997)
Chen, Xuelei, Hindmarsh, Mark, Kamionkowski, Marc, Liddle, Andrew R
The one-texture universe, introduced by Davis in 1987, is a homogeneous mapping of a scalar field with an $S^3$ vacuum into a closed universe. It has long been known to mathematicians that such...
Scaling and Small Scale Structure in Cosmic String Networks (1996)
Vincent, Graham R., Hindmarsh, Mark, Sakellariadou, Mairi
We examine the scaling properties of an evolving network of strings in Minkowski spacetime and study the evolution of length scales in terms of a 3-scale model proposed by Austin, Copeland and Kibble...
Universality and Critical Phenomena in String Defect Statistics (1996)
The idea of biased symmetries to avoid or alleviate cosmological problems caused by the appearance of some topological defects is familiar in the context of domain walls, where the defect statistics...
Cosmic Strings and Coherence (1996)
Hindmarsh, Mark, Sakellariadou, Mairi, Vincent, Graham R.
Cosmic strings provide a radically different paradigm for the formation of structure to the prevailing inflationary one. They afford some extra technical complications: for example, the calculation...
Correlations in Cosmic String Networks (1996)
Vincent, Graham R., Hindmarsh, Mark, Sakellariadou, Mairi
We investigate scaling and correlations of the energy and momentum in an evolving network of cosmic strings in Minkowski space. These quantities are of great interest, as they must be understood...
Analytic scaling solutions for cosmic domain walls (1996)
A relativistic generalisation of a well-known method for approximating the dynamics of topological defects in condensed matter is constructed, and applied to the evolution of domain walls in a...
Smooth metrics for snapping strings (1995)
Gregory, Ruth, Hindmarsh, Mark
We construct two possible metrics for abelian Higgs vortices with ends on black holes. We show how the detail of the vortex fields smooths out the nodal singularities which exist in the idealized...
Where are the Hedgehogs in Nematics? (1995)
In experiments which take a liquid crystal rapidly from the isotropic to the nematic phase, a dense tangle of defects is formed. In nematics, there are in principle both line and point defects...
Cosmological Perturbations from Cosmic Strings (1994)
Some aspects of the theory of cosmological perturbations from cosmic strings and other topological defects are outlined, with particular reference to a simple example: a spatially flat CDM-dominated...
This work is based on a paper with Margaret James, to appear in Phys Rev D. In it we showed that the dipole moment of the sphaleron has its origin in two components: a ring of electric current...
Small Scale Microwave Background Fluctuations from Cosmic Strings (1993)
The Cosmic Microwave Background (CMB) fluctuations at very small angular scales (less than $10'$) induced by matter sources are computed in a simplified way. The result corrects a previous formula...
Thermal Fluctuations at Second Order Phase Transitions (1993)
Hindmarsh, Mark, Rivers, R. J.
We construct a new coarse-grained effective potential which enables us to estimate the probabilities of thermal fluctuations above an arbitrary threshold at different length scales.
Formation of Topological Defects at First Order Phase Transitions (1993)
Hindmarsh, Mark, Brandenberger, Robert, Davies, Anne-Christine
We analyze the evolution of scalar and gauge fields during first order phase transitions and show how the Kibble mechanism for the formation of topological defects emerges from the underlying...
The Origin of the Sphaleron Dipole Moment (1993)
Hindmarsh, Mark, James, Margaret
By providing a suitable definition of the electromagnetic field off the Higgs vacuum, we show that within the sphaleron there is a monopole-antimonopole pair with quantized charges, and a loop of...
Generalized Semilocal Theories and Higher Hopf Maps (1992)
Hindmarsh, Mark, Holman, Richard, Kephart, Thomas W., Vachaspati, Tanmay
\def\mon{S^3\stackrel{S^1}{\rightarrow}S^2} \def\inst{S^7\stackrel{S^3}{\rightarrow}S^4} \def\octo{S^{15}\stackrel{S^7}{\rightarrow}S^8} In semilocal theories, the vacuum manifold is fibered in a...
Semilocal Topological Defects (1992)
Semilocal defects are those formed in field theories with spontaneously broken symmetries, where the vacuum manifold $M$ is fibred by the action of the gauge group in a non-trivial way. Studied in...