John March-Russell
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View article: QSHS: an axion dark matter resonant search apparatus
QSHS: an axion dark matter resonant search apparatus Open
We describe a resonant cavity search apparatus for axion dark matter constructed by the quantum sensors for the hidden sector collaboration. The apparatus is configured to search for QCD axion dark matter, though also has the capability to…
View article: Dark Matter EFT landscape probed by QUEST-DMC
Dark Matter EFT landscape probed by QUEST-DMC Open
We present the projected sensitivity to non-relativistic Effective Field Theory (EFT) operators for dark matter (DM) direct detection using the QUEST-DMC experiment. QUEST-DMC employs superfluid Helium-3 as a target medium and measures ene…
View article: De Sitter space constraints on brane tensions and couplings
De Sitter space constraints on brane tensions and couplings Open
A bstract We argue for the existence of bounds on the tensions of p -branes in de Sitter space in terms of the Hubble rate and the strength of a class of Chern-Simons-like couplings. The world-volume couplings involve Abelian 1-form gauge …
View article: A Prototype Atom Interferometer to Detect Dark Matter and Gravitational Waves
A Prototype Atom Interferometer to Detect Dark Matter and Gravitational Waves Open
The AION project has built a tabletop prototype of a single-photon long-baseline atom interferometer using the 87Sr clock transition - a type of quantum sensor designed to search for dark matter and gravitational waves. Our prototype detec…
View article: Chern-Simons induced thermal friction on axion domain walls
Chern-Simons induced thermal friction on axion domain walls Open
A bstract We study the dynamics and interactions of the solitonic domain walls that occur in realistic axion electrodynamics models including the Chern-Simons interaction, aϵ μνλσ F μν F λσ , between an axion a ( x ) of mass m a , and a ma…
View article: Dark Matter Attenuation Effects: Sensitivity Ceilings for Spin-Dependent and Spin-Independent Interactions
Dark Matter Attenuation Effects: Sensitivity Ceilings for Spin-Dependent and Spin-Independent Interactions Open
Direct detection experiments aimed at uncovering the elusive nature of dark matter (DM) have made significant progress in probing ever lower cross-sections for DM-nucleon interactions. At the same time, an upper limit in the cross-section …
View article: De Sitter space constraints on brane tensions and couplings
De Sitter space constraints on brane tensions and couplings Open
We argue for the existence of bounds on the tensions of $p$-branes in de Sitter space in terms of the Hubble rate and the strength of a class of Chern-Simons-like couplings. The world-volume couplings involve Abelian 1-form gauge fields in…
View article: Chern-Simons Induced Thermal Friction on Axion Domain Walls
Chern-Simons Induced Thermal Friction on Axion Domain Walls Open
We study the dynamics and interactions of the solitonic domain walls that occur in realistic axion electrodynamics models including the Chern-Simons interaction, $aε_{μνλσ}F^{μν} F^{λσ}$, between an axion $a(x)$ of mass $m_a$, and a massle…
View article: Centralized design and production of the ultra-high vacuum and laser-stabilization systems for the AION ultra-cold strontium laboratories
Centralized design and production of the ultra-high vacuum and laser-stabilization systems for the AION ultra-cold strontium laboratories Open
This paper outlines the centralized design and production of the ultra-high-vacuum sidearm and laser-stabilization systems for the AION Ultra-Cold Strontium Laboratories. Commissioning data on the residual gas and steady-state pressures in…
View article: Chern-Simons bubbles: Lopsided false vacuum decay in axion electrodynamics
Chern-Simons bubbles: Lopsided false vacuum decay in axion electrodynamics Open
We study axion electrodynamics, including the Chern-Simons interaction term, in the presence of parallel background electric and magnetic fields, as can for example occur in certain models of axion inflation and in the study of dyonic blac…
View article: Long nanomechanical resonators with circular cross-section
Long nanomechanical resonators with circular cross-section Open
Fabrication of superconducting nanomechanical resonators for quantum research, detectors and devices traditionally relies on a lithographic process, resulting in oscillators with sharp edges and a suspended length limited to a few 100 micr…
View article: Searching for wave-like dark matter with QSHS
Searching for wave-like dark matter with QSHS Open
In 2021 the Quantum Sensors for the Hidden Sector (QSHS) collaboration was founded in the UK and received funding to develop and demonstrate quantum devices with the potential to detect hidden sector particles in the \mu eV to 100 \mu …
View article: Centralised Design and Production of the Ultra-High Vacuum and Laser-Stabilisation Systems for the AION Ultra-Cold Strontium Laboratories
Centralised Design and Production of the Ultra-High Vacuum and Laser-Stabilisation Systems for the AION Ultra-Cold Strontium Laboratories Open
This paper outlines the centralised design and production of the Ultra-High-Vacuum sidearm and Laser-Stabilisation systems for the AION Ultra-Cold Strontium Laboratories. Commissioning data on the residual gas and steady-state pressures in…
View article: Quantum Sensors for the Hidden Sector (QSHS) - A Summary of Our First Year!
Quantum Sensors for the Hidden Sector (QSHS) - A Summary of Our First Year! Open
In 2021 the Quantum Sensors for the Hidden Sector (QSHS) collaboration was founded in the UK. We received funding as part of the Quantum Technologies for Fundamental Physics programme to develop and demonstrate quantum devices with the pot…
View article: Report on scipost_202210_00019v1
Report on scipost_202210_00019v1 Open
In 2021 the Quantum Sensors for the Hidden Sector (QSHS) collaboration was founded in the UK and received funding to develop and demonstrate quantum devices with the potential to detect hidden sector particles in the µeV to 100 µeV mass wi…
View article: Dark photon stars: formation and role as dark matter substructure
Dark photon stars: formation and role as dark matter substructure Open
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 comprise all or a substantial fraction of the observed dark…
View article: Micro-Bose/Proca dark matter stars from black hole superradiance
Micro-Bose/Proca dark matter stars from black hole superradiance Open
We study the production of heavy, $μ\gtrsim 1$ TeV, bosonic spin $s=0,1$ dark matter (DM) via the simultaneous processes of Hawking evaporation and superradiance (SR) from an initial population of small, $\lesssim 10^6$ kg, primordial blac…
View article: Evaporating primordial black holes, the string axiverse, and hot dark radiation
Evaporating primordial black holes, the string axiverse, and hot dark radiation Open
We show that primordial black holes (PBHs) develop non-negligible spins through Hawking emission of the large number of axion-like particles generically present in string theory compactifications. This is because scalars can be emitted in …
View article: Axiverse Strings
Axiverse Strings Open
If the QCD axion solves the strong CP problem then light axion-like-particles (ALPs) are expected to be ubiquitous in string theory - the string axiverse. Such ALPs can be the QCD axion and constitute dark matter (DM) or radiation, quintes…
View article: Axiverse Strings
Axiverse Strings Open
If the QCD axion solves the strong CP problem then light axion-like-particles (ALPs) are expected to be ubiquitous in string theory - the string axiverse. Such ALPs can be the QCD axion and constitute dark matter (DM) or radiation, quintes…
View article: Reproductive freeze-in of self-interacting dark matter
Reproductive freeze-in of self-interacting dark matter Open
We present a mechanism for dark matter (DM) production involving a\nself-interacting sector that at early times is ultra-relativistic but\nfar-underpopulated relative to thermal equilibrium (such initial conditions\noften arise, e.g., from…
View article: Towards a Swampland Global Symmetry Conjecture using weak gravity
Towards a Swampland Global Symmetry Conjecture using weak gravity Open
It is widely believed and in part established that exact global symmetries\nare inconsistent with quantum gravity. One then expects that approximate global\nsymmetries can be quantitatively constrained by quantum gravity or swampland\nargu…
View article: QCD, Flavor, and the de Sitter Swampland
QCD, Flavor, and the de Sitter Swampland Open
The refined swampland de Sitter conjecture (SdSC) is a proposed constraint on the form of the total potential in a theory including quantum gravity. According to this conjecture potentials possessing metastable de Sitter vacua are in the s…
View article: AION: An Atom Interferometer Observatory and Network
AION: An Atom Interferometer Observatory and Network Open
We outline the experimental concept and key scientific capabilities of AION (Atom Interferometer Observatory and Network), a proposed UK-based experimental programme using cold strontium atoms to search for ultra-light dark matter, to expl…
View article: Hot Gravitons and Gravitational Waves From Kerr Black Holes in the Early Universe
Hot Gravitons and Gravitational Waves From Kerr Black Holes in the Early Universe Open
Any abundance of black holes that was present in the early universe will evolve as matter, making up an increasingly large fraction of the total energy density as space expands. This motivates us to consider scenarios in which the early un…
View article: Unified Maximally Natural Supersymmetry
Unified Maximally Natural Supersymmetry Open
Maximally Natural Supersymmetry, an unusual weak-scale supersymmetric extension of the Standard Model based upon the inherently higher-dimensional mechanism of Scherk-Schwarz supersymmetry breaking (SSSB), possesses remarkably good fine tu…
View article: Baryogenesis via particle-antiparticle oscillations
Baryogenesis via particle-antiparticle oscillations Open
CP violation, which is crucial for producing the baryon asymmetry of the\nUniverse, is enhanced in particle-antiparticle oscillations. We study\nparticle-antiparticle oscillations (of a particle with mass O(100 GeV)) with CP\nviolation in …