Many well theoretically motivated models of ultralight dark matter are expected to give rise to feeble oscillatory forces on macroscopic objects. Optically trapped sensors have high force sensitivies but have remained relatively unexplored in this context. In this talk we propose a new, tunable, optically trapped sensor specifically designed to detect such forces. Our design features a...
In a broad class of theories, the accumulation of ultralight dark matter (ULDM) with particles of mass $10^{-22}~\textrm{eV} < m_{\phi} < 1~\textrm{eV}$ leads to the formation of long-lived bound states known as boson stars. When the ULDM exhibits self-interactions, prodigious bursts of energy carried by relativistic bosons are released from collapsing boson stars in bosenova explosions. We...
Axions are well-motivated dark matter candidates originally proposed to resolve the strong CP problem in quantum chromodynamics. In this talk, I present recent results from the Haloscope At Yale Sensitive To Axion Cold Dark Matter (HAYSTAC) experiment, which searches for axion dark matter using a tunable microwave cavity coupled to a quantum squeezed state receiver. HAYSTAC has scanned axion...
False vacuum decay (FVD) is at the heart of many open questions in cosmology and fundamental physics including, for example, eternal inflation, baryon asymmetry, and Higgs stability. Semiclassical lattice simulations have recently been proposed as a way of describing the phenomenon in real time. These numerical methods will be complemented by upcoming tabletop experiments based on cold-atom...
The Relic Axion Detector Exploratory Setup (RADES) collaboration works on the development of new techniques for axion searches. Axions are hypothetical pesudoscalar pseudoNambu-Goldstone bosons that appear as part of the solution to the the strong CP problem of QCD. At the same time they could also be the answer to one of the most puzzling questions on cosmology, the Dark Matter problem.
In...
We investigate how matter density distributions affect thin-wall bubble formation in the asymmetron mechanism, a scalar–tensor theory with a universal coupling to matter and explicit symmetry-breaking, and analyse the stability of its metastable state. We show that the screening mechanism of the asymmetron inside dense objects induces a surface tension associated with the boundary of the...
The axion is a well-motivated dark matter candidate that was originally proposed to solve the Strong CP problem. The talk presents the development of a dielectric Fabry-Perot cavity haloscope within the Imperial College Quantum enhanced Particle Astrophysics (QuEPA) project. Our approach is optimised to search for axion dark matter in the 125–250 µeV mass range (30–60 GHz) via photon...
Atom interferometry utilizes matter-wave quantum interference. Different quantum states of an ultracold atom ensemble follow different free-fall trajectories through spacetime and experience the spatial and temporal variations of the gravitational potential. Variations in the gravitational field are encoded in the resulting matter-wave interference pattern. With the precise control of quantum...
We present a science case for the QUEST experiment at Cardiff University as a probe of the ground state of gravitational entanglement. The foundations of quantum mechanics have been tested with exceptional levels of rigor, mathematically and experimentally. However, the theoretical framework in which the mathematical formalism is constructed presumes a classical, definite space-time as its...
The LUX-ZEPLIN (LZ) experiment uses a dual-phase xenon time-projection chamber designed to search for rare interactions between dark matter and ordinary matter. In this talk, I present LZ’s latest results using an expanded exposure and improved background modeling, yielding the most stringent constraints to date on spin-independent WIMP–nucleon and spin-dependent WIMP–neutron scattering down...
The toolkit of quantum technologies developed in atomic, molecular and optical physics are ideally suited to enhance the search for dark matter axions with masses above ~40 µeV. I will present an overview of a new experimental effort under construction at Imperial College, developing technologies to detect DFSZ axions with masses above 120 µeV. We plan to use a large mode area Fabry-Perot...
Determining the nature of the neutrino mass is an extremely difficult technological problem that appears likely to require unconventional solutions. To this end, our group has been developing single-molecule fluorescence imaging based sensors to tag the individual Ba2+ ions produced in the decay of xenon-136 through integrated photonic chips with organic sensing monolayers. Such structures...
Proposed theories of harmonizing gravity and quantum mechanics at low energies suggest novel features such as fluctuations in the spacetime metric and collapse of massive quantum superpositions. How can these features be probed experimentally?
We have recently shown how high-precision tabletop laser interferometers can distinguish different classes of spacetime fluctuations as characterized...
Cryogenic transition edge sensors (TESs) are single photon detectors featuring excellent energy resolution below 10% and high quantum efficiency at optical and near-infrared wavelengths. If black-body backgrounds can be suppressed to sufficiently low levels, such detectors would be ideally suited for experiments searching for photon-axion conversion at these wavelengths such as...
Exploring the vast spectrum of high-frequency gravitational waves (HFGWs) will require a variety of experimental strategies. Among the most promising detectors are electromagnetic resonators like microwave cavities and lumped-element circuits placed in large electromagnetic fields. Such detectors will always respond electromagnetically (Gertsenshtein effect) and deform mechanically at the same...
The axion, as well as being a proposed solution to the strong CP problem, is a well-motivated candidate for dark matter [1]. The Quantum Enhanced Particle Astrophysics (QuEPA) project at Imperial College London looks to detect axions with a microwave cavity and trapped electrons. Towards this goal, a dielectric Fabry-Perot cavity has been developed as a dark matter haloscope to convert axions...
Long-baseline atom interferometers based on the ultranarrow optical clock transition of strontium are currently being developed for fundamental physics by several consortia, including the US-UK collaboration MAGIS-100 and AION in the UK. These novel quantum sensors operate at the intersection of atom interferometry and optical clocks and aim to build and operate a 100-metre baseline atom...
We investigate the logarithmic form of $f(Q,T)$ gravity with two different choices of matter Lagrangian such as: $\mathcal{L}_m = p$ and $\mathcal{L}_m = -\rho$. The parameters of the model has been constrained using Cosmic Chronometers (CC) in combination with DES-SN5YR and Pantheon$^+$ Type Ia supernova datasets. We have observed that the deceleration parameter shows a smooth transition...
We investigate a modified geometric gravity theory within the framework of symmetric teleparallelism, wherein gravitation is governed by the non-metricity scalar $Q$. In this context, we propose and analyze an exponential model given by $f(Q) = Q + \eta_1 Q_0 \left(1 - e^{-\eta_2 \sqrt{Q/Q_0}}\right)$, which enables a smooth and theoretically consistent deviation from General Relativity. This...
Ultracold molecules offer a platform for tabletop tests of fundamental physics, including precision measurements of the electron’s electric dipole moment (eEDM), where heavy polar molecules provide greatly enhanced sensitivity compared to atoms. Such experiments are interferometric in nature, making long interrogation times essential for improved sensitivity. This can be achieved either by...
