This talk will be an elementary introduction to cosmological theories that replace the big bang with a smooth, classical transition from contraction to expansion in order to address many of the fundamental problems of cosmology.

**Sign up here by 2pm tomorrow, Thursday**

One of the main goals of modern observational cosmology is to constrain or detect a stochastic background of primordial gravitational waves. Realizing this goal will rely on highly accurate measurements of the B-mode signature in the cosmic microwave background (CMB). I will give a brief overview of a particular dedicated B-mode experiment: the…

The tension between measurements of the Hubble constant (H0) as determined from the "local" and "distant" Universe persists. The Carnegie-Chicago Hubble Program was designed to provide a calibration of the Type Ia Supernovae (SNe Ia) completely independent of the Leavitt Law for Cepheid variables. Our use of distances determined via the tip of…

In even the cleanest regions of the sky, polarized emission from our Galaxy is a limiting contaminant for the detection of primordial gravitational waves via a B-mode polarization signature in the Cosmic Microwave Background (CMB). In this talk, I will first review the physics of dust polarization and present models of the physical properties…

We show how kSZ tomography measures a bispectrum containing a cosmological power spectrum of the velocity field and an astrophysical power spectrum of the electron density. While these are degenerate up to an overall amplitude, scale-dependent effects on large scales are much better constrained by the inclusion of kSZ on top of galaxy…

The main purpose of this talk is to describe, by way of a concrete example, how the field of numerical relativity contributes to our understanding of asymptotically AdS spacetimes. I will begin by motivating these studies in terms of gauge/gravity duality, heavy ion physics, and gravitational collapse. I will then describe in detail results…

The B-mode polarization, a parity-odd component of polarization anisotropies on the cosmic microwave background (CMB), is a unique probe of primordial gravitational waves from the cosmic inflation. One of the challenges for the measurement is mitigation of the low-frequency noise, also called the 1/f noise, which…

We motivate the study of modified gravity theories and the role these modifications may play in addressing open questions about the formation and structure of black holes.

We discuss theoretical challenges in studying modified gravity theories and outline current work on a numerical study of gravitational collapse and black hole…

On galactic scales, structure is gravitationally held by dark matter, while stars and gas present merely an “icing on the cake.” In spite of their dominance over the matter budget in the universe, particle constituents of dark matter have eluded detection and characterization to the present day. This talk will focus on a variety of promising…

Over the last twenty years, there has been growing evidence that our universe is dominated by dark energy. The nature of this dark energy remains a mystery. Is it the signature of the breakdown of general relativity or vacuum energy associated with quantum gravity? I will review the current observations and note…

Observations of redshifted 21-cm emission of neutral hydrogen are a rapidly growing area of cosmology research. Measurements across a wide range of radio frequencies allow us to access redshifts that encompass a vast comoving volume, spanning both cosmic dawn and the formation of large-scale structure. I will describe two new experiments,…

**Xue (Sherry) Song, Princeton University**

"Journal Club Discussion of Watts et al. (2018) [CLASS Collaboration]"

The paper is available at https://arxiv.org/abs/1801.01481 .**Yaqiong Li, Princeton University**

"The Microwave SQUID…

The Advanced ACTPol upgrade on the Atacama Cosmology Telescope aims to improve the measurement of the cosmic microwave background anisotropies and polarization, using four new dichroic detector arrays fabricated on 150-mm silicon wafers. In 2016, the Atacama Cosmology Telescope began mapping approximately half the sky with increased sensitivity…

## By Year

## By Category

- Astroparticle Seminar
- Atomic Physics Seminar
- Biophysics Seminar
- Condensed Matter Seminar
- Dark Cosmo Seminar
- Distinguished Lecture Series
- Donald R. Hamilton Colloquium
- Donald R. Hamilton Lecture
- Equity Diversity and Inclusion Initiative
- FPO
- Gravity Group Seminar
- Gravity Initiative Seminar
- High Energy Experiment Seminar
- High Energy Theory Seminar
- Mathematical Physics Seminar
- Particle Physics Seminar
- PCTS Seminar
- Phenomenology Seminar
- Princeton Quantum Colloquium
- Quantum Initiative
- Special Event
- Special Seminar
- Statistical Mechanics Seminar