NEST (Noble Element Simulation Technique) is a semi-empirical model that describes the charge and light signals generated by particle interactions in liquid noble elements. This tool is particularly effective for simulating the behavior of dark matter detectors that utilize liquid noble elements as target material. In this seminar, I will explain how NEST can be employed to simulate the detector response of liquid-xenon-based detectors used for direct dark matter search.

When a Kerr black hole is perturbed, it undergoes damped oscillations described by quasi-normal modes (QNMs) with decay times and complex frequencies completely determined by the black hole's mass and spin. QNMs can be used to describe the gravitational-wave signal produced by the remnant of a binary black hole merger. This will be an introductory talk about QNMs and the tests of general relativity that can be performed by observing this "ringdown" phase, including key results from GW150914.

In quantum models of space-time, the metric is often replaced by more fundamental entities, such as spins and Lorentz invariants in spin-foam models, which describe the dynamics of loop quantum gravity. However, in general relativity, the metric field is almost completely determined by the causal structure. This raises the question: how is causality encoded in spin-foam models? In this seminar, I will introduce the basic ingredients of spin-foams and discuss how causality is encoded.

Contrary to isolated closed systems studied in most textbooks, physical systems in nature tend to interact with their environment. To make a measurement, one will need to have their system interact with a measurement device whose wavefunction is too complicated to write down. The observable universe interacts with the unobservable universe. These are examples of open quantum systems. In this talk, we will introduce dynamical maps and our approach in developing a theory for open quantum systems.

Gravitational microlensing is a powerful probe to measure the mass distribution of compact object populations. The simplest scenario is the point-source point-lens (PSPL) model, characterized by a time-symmetric light curve. Beyond PSPL, there are additional features that can show up under more complex conditions. We will also highlight upcoming microlensing surveys and their potential to detect compact objects, including compact objects related to dark matter.

This talk focuses on applications of emergent modified gravity. In this formulation, the spacetime is an emergent object with a nontrivial dependence on the phase space derived from modified structure functions resulting from the closure of modified constraints of the Hamiltonian formalism of gravity. Dynamical solutions of the spherically symmetric model include nonsingular black holes, new effects in gravitational collapse, and MOND-like effects at intermediate scales.

A complete model for dark matter should be able to capture most, if not all, of the well-known phenomenology. Many attempts have been made to paint a complete picture of dark matter which reveal interesting observables that can be probed directly or in-directly. Exotic models of dark matter can include self-interactions (SIDM) or dissipation channels that can lead to the formation of compact objects. I will give a brief discussion on dark matter models and highlight their observable signatures.

Although classically black holes could be characterized as perfect absorbers, this is no longer true once quantum effects are taken into account. In fact, black holes are not black: they “glow red” with radiation. In this talk, we will introduce the Hawking effect and illustrate how it can be used to cook up some eggs. Physical implications will be qualitatively reviewed. The focus will be on building an intuitive picture of the physics by utilizing order-of-magnitude estimates and toy models.

Compact objects like neutron stars, black holes, and white dwarfs are studied through various observational channels, but distinguishing them often majorly depends on assumed mass ranges. Are these mass ranges theoretically robust, or could different compact objects act as "imposters" within overlapping ranges? This talk explores the limitations and biases in current classification methods and discusses their broader implications for fundamental physics.

The precise measurement of the cosmic microwave background (CMB) has opened a window to connect fundamental physics with observations. If spacetime exhibited a strong quantum mechanical behavior before the Hot Big Bang, could we detect signatures of this regime today? In this introductory seminar, we explore how the study of correlations in the CMB sky can address this question, highlighting recent developments and possible future avenues for an effective, evidence-based approach to quantum gravity.

Gravitational wave signals carry characteristic information about the astrophysical properties of compact objects, their immediate environment, and the nature of gravity in the strong-field dynamical regime. Bayesian inference has been the go-to tool for extracting this information. This talk will introduce it, using a quasi-spherical binary black hole merger as an illustrative example while ensuring accessibility to a broader audience. I might conclude by sharing the sins of prior choices!

In this seminar, we will explore the interplay between quantum mechanics and general relativity by examining the behavior of a quantum clock in curved spacetime. Unlike a classical point mass, a quantum clock with nonzero position fluctuations cannot travel along a single geodesic. Instead, it behaves as an extended object influenced by tidal forces and a superposition of time dilations at different altitudes. Using a geometrical formulation of quantum mechanics, we will show that quantum correlations between spatial directions introduce a non-Riemannian structure to the spacetime experienced by the clock. A specific version of Finsler geometry provides a new setting for a combination of quantum and gravitational effects. The Finsler structure is parameterized by entropy and purity of the state, and uncertainty relations prevent it from being Riemannian. By unifying quantum and gravitational effects in a geometric framework, this approach offers new avenues for advancements in our understanding of quantum reference frames and their applications in semi-classical gravity.

Statistical mechanics is built upon the postulate of equal a priori probability: in equilibrium, all microstates compatible with a given macrostate are equally probable. Despite its remarkable success, this assumption remains controversial. Several proposals suggest replacing it with quantum mechanical ideas. In this talk, I will present some arguments for abandoning this additional postulate, as it can be viewed as a consequence of entanglement.

Next-generation galaxy surveys will cover large portions of the sky, which will provide an unprecedented opportunity to detect primordial non-Gaussianity (PNG), a parameter that can be used to differentiate between theories of inflation. In this talk, I will briefly overview two-point statistics, PNG, and redshift space distortions (RSDs), and motivate why a proper treatment of RSDs will be required to make a statistically significant detection of PNG in upcoming surveys, such as SPHEREx.

We physicists tend to look at pop science buzzwords like wormholes or warp drives - things that made us jump up and down with excitement 10/15 years ago - with distaste and boredom. But it would be a mistake to think that there's nothing interesting or valuable within these concepts. On this special Valentines Day talk, I will discuss the Ellis Wormhole solution. By studying how things break in a wormhole, we will have a better understanding of concepts foundational to GR.

This talk presents a study on the effects of neutrino oscillations in binary neutron star (BNS) merger simulations. I will talk about how we implement a subgrid model to simulate neutrino mixing with a 3D GRMHD code using M1 neutrino radiation transport. This is the first-ever simulation of BNS mergers incorporating neutrino flavor conversions. Our results reveal significant differences in the ejecta composition, neutrino luminosities, and nucleosynthesis features for the post-merger phase.

Gravitational waves offer a new way to measure cosmic distances, independent of traditional methods. In this talk, I’ll start with the cosmic distance ladder and its challenges before introducing gravitational waves as standard sirens. I’ll then explore the two main approaches for cosmology—bright sirens and statistical dark sirens. Time permitting, I’ll touch on other techniques, including Love and spectral sirens, and their role in measuring the Hubble constant and the universe’s expansion.

Combining (flat-space) Lorentz-invariance with quantum mechanics in D=4 you inevitably describe a Quantum Field Theory (QFT), so the widespread interest in QFTs is understandable. Much more mysterious for many students is the passage to gauge theory, which introduces many sophisticated mathematical notions prone to overwhelming the uninitiated. Just as QFT arises as a necessary framework assuming certain basic principles, we will describe reasonable sounding theories for which non-abelian gauge theory is the necessary framework. The concrete statement we will argue is the following: a unitary, local, and Lorentz-invariant theory of massless, self-interacting, spin-1 particles in D=4 is necessarily a non-abelian gauge theory. Time allowing, we may discuss other interesting aspects of gauge theory relevant to my research.

Spinors, which are used to describe fermions, play an integral role in modern physics. Despite their importance, after taking 2 semesters of QM and then another 2 semesters of QFT, I was still unable to define exactly what they were, and I wanted to remedy that. This talk will dive straight to the heart of the definition given by Riesz in 1947, while putting the technical jargon in more physics-y terms. Then I will discuss very briefly the origin of the ½ when referring to spinors as "spin ½ particles," and a geometric picture of how the spinors turn into the spinor fields we see in QFT. 

The LUX-ZEPLIN (LZ) experiment is a direct detection search for Weakly Interacting Massive Particles (WIMPs) dark matter. A significant source of backgrounds arises from events near the detector’s edges, which are mitigated by defining a fiducial volume (FV) that excludes these regions. The radial boundary of the FV is set using the effective detector wall. To enhance sensitivity by maximizing the FV, this wall must be accurately modeled in a way that captures time-dependent behavior.

Extreme cosmic phenomena act as natural particle accelerators, allowing us to explore particle interactions at such high energies. To understand these energetic environments, we can utilize Very-High-Energy (VHE) gamma rays as effective messengers. In this talk, I will discuss the production mechanisms of VHE gamma rays and their astrophysical sources. In addition, I will highlight the role of the High-Altitude Water Cherenkov (HAWC) observatory in detecting VHE gamma rays.

With the recent discovery of an ultra-high energy (>100 PeV) neutrino by KM3NeT, and the ongoing development of several next-generation detectors, we will soon have the opportunity to explore the universe at the highest energies. In this talk, I will highlight the scientific opportunities presented by ultra-high energy neutrinos and the unique methods by which we may detect them.