A5033947596- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Black Holes and Theoretical Physics
- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Noncommutative and Quantum Gravity Theories
- Dark Matter and Cosmic Phenomena
- Quantum Mechanics and Applications
- Geophysics and Gravity Measurements
- Particle physics theoretical and experimental studies
- Complex Systems and Time Series Analysis
- Radioactive Decay and Measurement Techniques
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Advanced Frequency and Time Standards
- Gamma-ray bursts and supernovae
- Geophysics and Sensor Technology
- Galaxies: Formation, Evolution, Phenomena
- Computational Physics and Python Applications
California Institute of Technology
2021-2025
Abstract The 15 yr pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) shows positive evidence presence of a low-frequency gravitational-wave (GW) background. In this paper, we investigate potential cosmological interpretations signal, specifically cosmic inflation, scalar-induced GWs, first-order phase transitions, strings, and domain walls. We find that, with exception stable strings field theory origin, all these models can...
The gravity from the quantum entanglement of space-time (GQuEST) experiment uses tabletop-scale Michelson laser interferometers to probe for fluctuations in space-time. We present a practicable interferometer design featuring novel photon-counting readout method that provides unprecedented sensitivity, as it is not subject interferometric standard limit. evaluate potential this measure motivated by recent “geontropic” models. accelerated accrual Fisher information offered enables GQuEST...
We model vacuum fluctuations in quantum gravity with a scalar field, characterized by high occupation number, coupled to the metric. The number of is given thermal density matrix, whose form motivated energy, which have been shown be conformal near light-sheet horizon. For experimental measurement interest an interferometer, size energy fixed area surface bounding volume spacetime being interrogated interferometer. compute interferometer response these ``geontropic'' scalar-metric...
Quantum fluctuations in spacetime can, some cases, lead to distortion astronomical images of faraway objects. In particular, a stochastic model quantum gravity predicts an accumulated fluctuation the path length $\mathrm{\ensuremath{\Delta}}L$ with variance $⟨\mathrm{\ensuremath{\Delta}}{L}^{2}⟩\ensuremath{\sim}{l}_{p}L$ over distance $L$, similar random walk, and assuming no spatial correlation above ${l}_{p}$; it has been argued that such effect is ruled out by observation sharp from...
We study quantum fluctuations in the light-cone metric of 4D Einstein-Hilbert action via dimensional reduction to Jackiw-Teitelboim (JT) gravity. In particular, we show that, Einstein gravity, causal development a region flat Minkowski spacetime, near horizon defined by light sheets, can be described an effective two-dimensional dilaton theory. This enables us make use known solutions JT action, where spacetime position has uncertainty due fluctuations. then directly related original...
Dark matter substructure, such as primordial black holes (PBHs) and axion miniclusters, can induce phase shifts in pulsar timing arrays (PTAs) measurements due to gravitational effects. In order gain a more realistic forecast for the detectability of models dark with PTAs, we propose Bayesian inference framework search generated by PBHs perform analysis on mock PTA data. For most PBH masses constraints abundance agree previous (frequentist) analyses (without data) (1) factors. This further...
We search for a first-order phase transition gravitational wave signal in 45 pulsars from the NANOGrav 12.5-year dataset. find that data can be modeled terms of strong first order taking place at temperatures below electroweak scale. However, we do not observe any preference phase-transition interpretation over standard astrophysical supermassive black hole mergers; but expect to gain additional discriminating power with future datasets, improving noise ratio and extending sensitivity window...
A bstract Models of Dark Matter (DM) can leave unique imprints on the Universe’s small scale structure by boosting density perturbations scales. We study capability Pulsar Timing Arrays to search for, and constrain, subhalos from such models. The models DM we consider are ordinary adiabatic in ΛCDM, QCD axion miniclusters, with early matter domination, vector produced during inflation. show that largely due tidal stripping effects Milky Way, is out reach for PTAs. Axion miniclusters may be...
We study signatures of macroscopic dark matter (DM) in current and future gravitational wave (GW) experiments. Transiting DM with a mass $\ensuremath{\sim}{10}^{5}--{10}^{15}\text{ }\text{ }\mathrm{kg}$ that saturates the local density can be potentially detectable by GW detectors, depending on baseline detector strength force mediating interaction. In context laser interferometers, we derive gauge invariant observable due to transiting DM, including Shapiro effect (gravitational time delay...
The GQuEST (Gravity from the Quantum Entanglement of Space-Time) experiment uses tabletop-scale Michelson laser interferometers to probe for fluctuations in space-time. We present an interferometer design featuring a novel photon counting readout method that provides unprecedented sensitivity, as it is not subject interferometric standard quantum limit. evaluate potential this measure space-time motivated by recent `geontropic' gravity models. accelerated accrual statistical power offered...
We develop a general framework for calculating the leading-order, fully-relativistic contributions to gravitational phase shift in single-photon atom interferometers within context of linearized gravity. show that gradiometer observable, which only depends on interferometer propagation phase, can be written terms three distinct contributions: Doppler shift, accounts tidal displacement atoms along baseline, Shapiro delay arrival time photons at atom-light interaction points, and Einstein...
We present an explicitly gauge-invariant observable of {\em any} general gravitational perturbation, $h_{\mu\nu}$ (\textit{not} necessarily due to waves (GWs)), in a laser interferometry-based GW detector, identifying the signature as proper time elapsed beamsplitter observer, between two events: when photon passes through beamsplitter, and same returns after traveling interferometer arm reflecting off far mirror. Our formalism applies simple Michelson interferometers can be generalized more...
We study quantum fluctuations in the lightcone metric of 4-d Einstein-Hilbert action via dimensional reduction to Jackiw-Teitelboim (JT) gravity. In particular, we show that, Einstein gravity, causal development a region flat Minkowski spacetime, near horizon defined by light sheets, can be described an effective two-dimensional dilaton theory. This enables us make use known solutions JT action, where spacetime position has uncertainty due fluctuations. then directly related original cone...
We study signatures of macroscopic dark matter (DM) in current and future gravitational wave (GW) experiments. Transiting DM with a mass $\sim10^5-10^{15}$ kg that saturates the local density can be potentially detectable by GW detectors, depending on baseline detector strength force mediating interaction. In context laser interferometers, we derive gauge invariant observable due to transiting DM, including Shapiro effect (gravitational time delay accumulated during photon propagation),...
Quantum fluctuations in spacetime can, some cases, lead to distortion astronomical images of faraway objects. In particular, a stochastic model quantum gravity predicts an accumulated fluctuation the path length $ΔL$ with variance $\langle ΔL^2\rangle\sim l_pL$ over distance $L$, similar random walk, and assuming no spatial correlation above $l_p$; it has been argued that such effect is ruled out by observation sharp from distant stars. However, other theories, as pixellon (modeled on...
We consider the effects of an attractive, long-range Yukawa interaction between baryons and dark matter (DM), focusing in particular on temperature pulsar timing observations neutron stars (NSs). show that such a fifth force, with strength modestly stronger than gravity at ranges greater tens kilometers (corresponding to mediator masses less $10^{-11} \text{eV}$), can dramatically enhance kinetic heating, capture, Doppler shifts relative plus short range interactions alone. Using coldest...
We model vacuum fluctuations in quantum gravity with a scalar field, characterized by high occupation number, coupled to the metric. The number of is given thermal density matrix, whose form motivated energy, which have been shown be conformal near light-sheet horizon. For experimental measurement interest an interferometer, size energy fixed area surface bounding volume spacetime being interrogated interferometer. compute interferometer response these "geontropic" scalar-metric...