751 citations · 2.5k across the 29 of their papers we have counts for
30 papers
Imperfect axions with no domain wall problem
Marco Gorghetto, Edward Hardy, Gilad Perez +1
Post-inflationary axion theories with domain wall number suffer from a domain wall problem. We show analytically, and confirm via simulations, that there is a region of pheno…
Post-inflationary axions: a minimal target for axion haloscopes
Marco Gorghetto, Edward Hardy
An axion-like-particle (ALP) in the post-inflationary scenario with domain wall number can be dark matter if the residual symmetry has a small explicit breakin…
Dark Photon Stars: Formation and Role as Dark Matter Substructure
Marco Gorghetto, Edward Hardy, John March-Russell +2
Any new vector boson with non-zero mass (a `dark photon' or `Proca boson') that is present during inflation is automatically produced at this time from vacuum fluctuations and can…
Axion Quasiparticles for Axion Dark Matter Detection
Jan Schütte-Engel, David J. E. Marsh, Alexander J. Millar +7
It has been suggested that certain antiferromagnetic topological insulators contain axion quasiparticles (AQs), and that such materials could be used to detect axion dark matter (D…
Observing Invisible Axions with Gravitational Waves
Marco Gorghetto, Edward Hardy, Horia Nicolaescu
If the Peccei-Quinn symmetry associated to an axion has ever been restored after inflation, axion strings inevitably produce a contribution to the stochastic gravitational wave bac…
More Axions from Strings
Marco Gorghetto, Edward Hardy, Giovanni Villadoro
We study the contribution to the QCD axion dark matter abundance that is produced by string defects during the so-called scaling regime. Clear evidence of scaling violations is fou…
Exploring Hamiltonian Truncation in
Joan Elias Miro, Edward Hardy
We initiate the application of Hamiltonian Truncation methods to solve strongly coupled QFTs in . By analysing perturbation theory with a Hamiltonian Truncation regulator, w…
Thermal Dark Energy
Edward Hardy, Susha Parameswaran
We present a novel source of dark energy, which is motivated by the prevalence of hidden sectors in string theory models and is consistent with all of the proposed swampland conjec…
Hearing without seeing: gravitational waves from hot and cold hidden sectors
Malcolm Fairbairn, Edward Hardy, Alastair Wickens
We study the spectrum of gravitational waves produced by a first order phase transition in a hidden sector that is colder than the visible sector. In this scenario, bubbles of the…
Axions from Strings: the Attractive Solution
Marco Gorghetto, Edward Hardy, Giovanni Villadoro
We study the system of axion strings that forms in the early Universe if the Peccei-Quinn symmetry is restored after inflation. Using numerical simulations, we establish the existe…
Higgs portal dark matter in non-thermal cosmologies
Edward Hardy
A scalar particle with a relic density set by annihilations through a Higgs portal operator is a simple and minimal possibility for dark matter. However, assuming a thermal cosmolo…
Glueball dark matter in non-standard cosmologies
Bobby Samir Acharya, Malcolm Fairbairn, Edward Hardy
Hidden sector glueball dark matter is well motivated by string theory, compactifications of which often have extra gauge groups uncoupled to the visible sector. We study the dynami…
Symmetric and Asymmetric Reheating
Edward Hardy, James Unwin
We study models in which the inflaton is coupled to two otherwise decoupled sectors, and the effect of preheating and related processes on their energy densities during the evoluti…
Stellar cooling bounds on new light particles: plasma mixing effects
Edward Hardy, Robert Lasenby
Strong constraints on the coupling of new light particles to the Standard Model (SM) arise from their production in the hot cores of stars, and the effects of this on stellar cooli…
Miniclusters in the Axiverse
Edward Hardy
If dark matter is an axion-like-particle a significant fraction of the present day relic abundance could be concentrated in compact gravitationally bound miniclusters. We study the…
Dirac vs Majorana gauginos at a 100 TeV collider
Giovanni Grilli di Cortona, Edward Hardy, Andrew J. Powell
We compare the prospects for observing theories with Majorana or Dirac gauginos at a future 100 TeV proton-proton collider. Calculating the expected discovery and exclusion regions…
Diphotons from Diaxions
Luis Aparicio, Aleksandr Azatov, Edward Hardy +1
We study models in which the 750 GeV diphoton excess is due to a scalar decaying to two pseudo-Nambu-Goldstone bosons that subsequently decay into two pairs of highly boosted photo…
The Massless Spectrum of Heterotic Compactifications
Xenia de la Ossa, Edward Hardy, Eirik Eik Svanes
We discuss the four-dimensional massless spectrum of supersymmetric Minkowski compactifications of ten-dimensional heterotic supergravity, including the anomaly cancelation conditi…
The QCD axion, precisely
Giovanni Grilli di Cortona, Edward Hardy, Javier Pardo Vega +1
We show how several properties of the QCD axion can be extracted at high precision using only first principle QCD computations. By combining NLO results obtained in chiral perturba…
The Heterotic Superpotential and Moduli
Xenia de la Ossa, Edward Hardy, Eirik Eik Svanes
We study the four-dimensional effective theory arising from ten-dimensional heterotic supergravity compactified on manifolds with torsion. In particular, given the heterotic superp…
Electroweak relaxation from finite temperature
Edward Hardy
We study theories which naturally select a vacuum with parametrically small Electroweak Scale due to finite temperature effects in the early universe. In particular, there is a sca…
Signatures of Large Composite Dark Matter States
Edward Hardy, Robert Lasenby, John March-Russell +1
We investigate the interactions of large composite dark matter (DM) states with the Standard Model (SM) sector. Elastic scattering with SM nuclei can be coherently enhanced by fact…
Big Bang Synthesis of Nuclear Dark Matter
Edward Hardy, Robert Lasenby, John March-Russell +1
We investigate the physics of dark matter models featuring composite bound states carrying a large conserved dark "nucleon" number. The properties of sufficiently large dark nuclei…
Annihilation Signals from Asymmetric Dark Matter
Edward Hardy, Robert Lasenby, James Unwin
In the simplest models of asymmetric dark matter (ADM) annihilation signals are not expected, since the DM is non-self-conjugate and the relic density of anti-DM is negligible. We…