I will present a new program of probing fundamental cosmology with spectroscopic galaxy surveys. This program builds on ideas of effective field theory and allows for sub-percent precision analytic understanding of galaxy clustering on large scales. I will highlight recent results of this program that include new measurements of fundamental cosmological parameters and constraints on new...
What statistics do we need to search for new physics? I will present a pedagogical overview of statistics beyond the galaxy power spectrum, and how they can be used to probe a wide variety of non-standard physics in inflation and beyond.
In this talk, I will outline our recent work on the SDSS BOSS 4-point correlation function and an apparent 7 sigma detection of parity violation. Then I will provide an update on progress with the Year 1 DESI data. I will conclude with a presentation of two new methods to ensure that the apparent result is of genuine cosmological origin.
Cosmological and astrophysical observations provide a unique opportunity to probe the fundamental properties of dark matter. Dark matter interactions with the Standard Model of particle physics, for example, can alter predictions from the standard cosmological model, permitting robust tests of new dark matter physics. In this talk, I will describe the impact that dark matter interactions have...
A major focus of the Snowmass2021 Cosmic Frontier report from the Topical Group on "Dark Energy and Cosmic Acceleration in the Modern Universe" (CF4) was on the compelling science cases for developing a Stage 5 Spectroscopic Facility. This Topical Group considered probes of both late-time cosmic acceleration and inflation based on observations of phenomena in the post-reionization era (z≲5),...
Scientific programs involving joint-analyses of galaxy surveys and CMB are increasingly gaining attention as they often increase the prospects to detect and characterize new signals by reducing systematics, cancelling cosmic variance and breaking degeneracies. The reconstruction of large-scale cosmological fluctuations at different epochs by using the CMB as a back-light will allow galaxy...
The advent of higher resolution and improved sensitivity CMB experiments in conjunction with deeper and wider galaxy surveys facilitates the exploration of cross correlations to detect weak signals. Among these, there is one of the two signals caused by the transverse velocity of halos: the moving lens effect. I will review the manifestation of the signal and summarize the perspective of...
The standard cosmological model has been thus far successful at predicting the clustering of galaxies on large physical scales. However, the standard model has not been thoroughly tested on smaller scales, where the spatial distribution of galaxies is affected by both cosmology and the physics of galaxy formation and evolution. Measuring galaxy clustering on small scales with the next...
Talk will be based on [arXiv:2403.03220][1] and references therein.
LSS surveys have significantly advanced from measuring angular clustering of galaxies using photographic plates to mapping three-dimensional clustering with spectroscopic fibers and robots. Meanwhile, statistical methods to analyze galaxy clustering and other biased tracers of LSS still rely on modeling two- and three-point...
In this talk, I will introduce a multi-fidelity emulation technique, designed to efficiently emulate summary statistics from cosmological simulations for high-dimensional parameter inference. Multi-fidelity emulation allows us to combine cosmological simulations of varying resolutions and volumes, enabling us to efficiently explore the high-dimensional parameter space of cosmological models...
The dynamics of early universe quantum fields generates a variety of signals amenable to observational tests. This talk will overview the theoretical origin of features in the power spectrum and beyond, including their motivation and structure in UV complete theory.
Large-scale structure observations are remarkably sensitive to primordial features. They are already more constraining than the cosmic microwave background today and will significantly exceed its sensitivity in the future. These oscillatory imprints in the primordial spectra arise from a departure from scale invariance during inflation or its alternatives and, therefore, provide important...
Upcoming large-scale structure (LSS) surveys will provide significant insight into the physics of the early Universe by searching for primordial non-Gaussianity (PNG). Whereas traditional approaches towards constraining PNG with LSS typically focus on phenomenological amplitudes, e.g., $f_{\rm NL}^{\rm loc.}$, which characterize a given "shape" of non-Gaussianity, there exist a range of...
An upcoming suite of cosmological probes of large-scale structure poses a unique opportunity to search for physics beyond the Standard Model. Particles with masses of order Hubble during inflation create a distinct, oscillatory signal in the squeezed limit of the bispectrum. Fully leveraging this property to uncover new physics, a pursuit known as the “cosmological collider”, necessitates a...
Axions, scalar fields with compact field spaces, are some of the most well-motivated candidates for physics beyond the Standard Model. In this talk, I will explain how inflationary correlations are uniquely sensitive to the topology of a scalar's field space, and can thus be used to distinguish axions from other light scalar fields even if they share the exact same action. As a proof of...
Local Primordial non-Gaussianity (LPNG) - the most easily measurable signature of inflationary physics from large-scale structures - will be a primary science target for current and future spectroscopic surveys. Maximally extracting information about the amplitude of PNG ($f_{NL}$) will require knowledge of galaxy formation physics, which can robustly be embedded in the values of bias...
We implement a novel formalism to constrain primordial non-Gaussianity of the local type from the large-scale modulation of the small-scale power spectrum. Our approach combines information about primordial non-Gaussianity contained in the squeezed bispectrum and the collapsed trispectrum of large-scale structure together in a computationally amenable and consistent way, while avoiding the...
Inflation remains one of the enigmas in fundamental physics. While it is difficult to distinguish different inflation models, information contained in primordial non-Gaussianity (PNG) offers a route to break the degeneracy. In galaxy surveys, the local type PNG is usually probed by measuring the scale-dependent bias in the galaxy power spectrum on large scales, where cosmic variance and...
Isocurvature perturbations with a blue power spectrum are one of the natural targets for the future large scale structure observations which are probing shorter length scales with greater accuracy. We present a Fisher forecast for the MegaMapper in its ability to detect CDM blue isocurvature perturbations. We construct the theoretical predictions in the EFTofLSS and bias expansion formalisms...
We explore a self-interacting neutrino cosmology in which neutrinos experience a delayed onset of free-streaming. We use the effective field theory of large-scale structure (LSS) to model matter distribution on mildly non-linear scales within the self-interacting neutrino cosmology for the first time. We perform the first combined likelihood analysis of BOSS full-shape galaxy clustering, weak...
Cosmology offers a unique opportunity to explore new physics with tiny interactions to the Standard Model particles. This is particular useful for studying new physics scenarios that address hierarchy problems while evading collider detections. I will briefly review three examples where data from the Large Scale Structure is crucial for identifying signals of solutions to hierarchical...
According to the Standard Model (SM), neutrinos begin to free-stream as the Universe cools to approximately 1.5 MeV, leaving distinctive imprints in cosmological observables. Interestingly, several analyses have revealed that some cosmic microwave background (CMB) data allow a cosmological scenario in which, due to self-interactions, the onset of neutrino-free streaming occurs close to the...
Neutrinos become nonrelativistic at late times and cluster anisotropically behind moving halos, forming neutrino wakes in the opposite direction to the halo motion and causing halos to slow down due to dynamical friction. We show that this effect can be best extracted from future large scale structure surveys via three point cross correlations involving galaxies and a tracer of the matter...
Upcoming cosmological surveys will probe the impact of a non-zero sum of neutrino masses on the growth of structures. These measurements are sensitive to the behavior of neutrinos at cosmic distances, making them a perfect testbed for neutrino physics beyond the standard model at long ranges. In this talk, I will introduce a novel signal from long-range self-interactions between neutrinos. In...
We explore the science prospects of a 14,000 deg$^2$ Kinematic Lensing (KL) survey with the Dark Energy Spectroscopic Instrument (DESI) and overlapping imaging surveys. KL infers the cosmic shear signal by jointly forward modeling the observed photometric image and velocity field of a disk galaxy. The latter can be constrained by placing multiple DESI fibers along the galaxy major and minor...
The $S_8$ tension between low-redshift galaxy surveys and the primary CMB signals a possible breakdown of the $\Lambda$CDM model.
Recently differing results have been obtained using low-redshift galaxy surveys and the higher redshifts probed by CMB lensing, motivating a possible time-dependent modification to the growth of structure.
We investigate a simple phenomenological model in which...
Ongoing and future spectroscopic surveys have prime sensitivities to comoving scales that became causal when the temperature of the Universe was in the ~1-100 eV regime. As such, these data are key to probing part of the so-called LambdaCDM `desert’ between e+e- annihilation and matter-radiation equality. This apparent desert has recently received renewed attention in light of possible...
Current and upcoming redshift surveys will measure the galaxy distribution over an increasing volume, probing interesting physical effects that become important on large physical scales. In particular, the local primordial non-Gaussianity $f_\rm{NL}$ will be measured to $\mathcal{O}(1)$ precision with SPHEREx, which will allow us to distinguish between multi-field and single-field models of...
While the current extragalactic spectroscopic surveys have accumulated millions of spectra of galaxies, more data are required for significant advancements in our understanding of the Universe and fundamental physical laws. To this end, the MUltiplexed Survey Telescope (MUST) is conceived by Tsinghua University to achieve this ambitious goal. Located at the Saishiteng Mountain, Qinghai...
The power spectrum of fluctuations in the Lyman alpha (Lya) forest can be used to measure the amplitude of the linear power spectrum on megaparsec scales, smaller than those accessible from galaxy surveys or the cosmic microwave background (CMB).
By combining CMB measurements from Planck with the Lya dataset of DESI one should be able to constrain running at the 0.002 level, a factor of 3...
The Lyman-a forest is a unique large-scale structure tracer at Mpc scales and below at high redshifts (2 < z < 4). One of the key advantages of the Lyman-a forest is that, since the density fields are only mildly non-linear at the respective redshifts, a much wider range of scales can be used to robustly probe cosmology than with most galaxy surveys, making the Lyman-a fluctuations a powerful...
Future Spectroscopic surveys will be designed to probe a large volume of the Universe with a galaxy density sufficient to measure the extremely-large-scale density fluctuations required to explore primordial non-Gaussianity and therefore inflation. In addition, combining the spectroscopic surveys with the next generation CMB-S4 experiment can provide the first 5 confirmation of the neutrino...
Models of dark sectors with a mass threshold exhibit significant cosmological signatures. When a relativistic species becomes non-relativistic before recombination and subsequently depletes in equilibrium, measurable effects on the cosmic microwave background (CMB) arise as entropy is transferred to lighter relativistic particles. Notably, if this transition occurs near z ∼ 20,000, the model...
Dwarf galaxies are essential probes of dark matter (DM) microphysics. Here, we assess potential DM constraints from future dwarf galaxy surveys. We find that observations of all satellites around one (two) Milky Way-mass host can rule out warm DM models with $m_{\mathrm{WDM}}=10~\mathrm{keV}$ ($20~\mathrm{keV}$). We show that the same data constrain the subhalo mass function in a...
Axion-like dark matter whose symmetry breaking occurs after the end of inflation predicts enhanced primordial density fluctuations at small scales. This leads to dense axion minihalos (or miniclusters) forming early in the history of the Universe.
Condensation of axions in the minihalos leads to the formation and subsequent growth of axion stars at the cores of these halos. If, like the...
The precision of present-day cosmological measurements has enabled exploration into the characteristics of dark matter and other particles within the dark sector. As measurement precision improves, discrepancies among various datasets have emerged, suggesting a necessity to move beyond the standard $\Lambda$CDM model. Extensions of $\Lambda$CDM that incorporate interactions within the dark...
I will discuss anisotropic (patchy) screening induced by the resonant conversion of cosmic microwave background (CMB) photons into light bosons in the dark sector as they cross non-linear large scale structure (LSS). Using kinetically mixed dark photon as an example, I will show how this conversion between CMB photon and light bosons leads to new CMB anisotropies that are correlated with LSS....
