Scientific Series

With increasingly precise measurements of the small-scale cosmic microwave background (CMB), the kinetic Sunyaev–Zel’dovich (kSZ) effect has emerged as a powerful probe of cosmology and astrophysics through cross-correlations with galaxy surveys. In this talk, I will review established applications, focusing on large-scale velocity reconstruction and its ability to test signatures of the early universe, such as primordial non-Gaussianity and compensated isocurvature perturbations. I will then introduce a new way to combine these data sets, which provides unique constraints on the distribution of ‘missing baryons’ at low redshifts, thereby opening a new window on baryonic feedback and cosmological inferences from the small-scale distribution of matter. Finally, I will explore the sensitivity of this statistic to the epoch of helium reionization, and compare its prospects to other proposed probes such as optical-depth fluctuations in the observed CMB.

Chirality is a fundamental feature of many-body physics, typically manifesting through the breaking of time-reversal symmetry. Yet a precise quantum information-theoretic characterization of chirality has remained elusive. A recent proposal defines a state as chiral if transforming it into its complex conjugate requires a circuit of large depth. Here, we rigorously establish many-body chirality for a broad family of two-dimensional stabilizer pure and mixed states. We also prove that these states are 4-partite chiral, but not 3-partite chiral.

Unimodular Henneaux-Teitelboim (HT) Gravity provides a fully diffeomorphism-invariant route to unimodular gravity by promoting the cosmological constant to a conjugate variable with an associated “unimodular time”. I will present two complementary applications. In 4D minisuperspace, starting from the connection representation, unimodular Hartle–Hawking wave packets yield a unitary inner product and normalizable states whose peaks track classical FRW dynamics. This work reframes “creation from nothing” as the emergence of a semiclassical Universe from interference of incident/reflected packets near the bounce, without invoking Vilenkin’s contour. In parallel, I will introduce a 2D cousin obtained via a centrally extended JT/KSY construction. In de Sitter quantum cosmology, superposing Lambda-eigenstates produces unitary evolution in unimodular time, controlled interference near T=0, and sharply separated WKB branches at late times. The same mechanism naturally accommodates transient quantum deformations of global dS and suggests a topology change interpretation in which contracting/expanding branches play the role of Universe/anti-Universe pairs.

In QFT, there exists a well-known set of relations between the scattering amplitudes of gluons in gauge theory and those of gravitons in gravity, known collectively as the double copy. There are many beautiful ways in which this is manifested, famous examples being the KLT double copy, the double copy in the CHY formalism, and the BCJ double copy. In this talk I will show how the double copy relation can be seen arising from amplitude expressions derived using twistor sigma models and the RSVW and Cachazo-Skinner formulae. This talk is based on 2406.04539, with Tim Adamo.

Gravitational wave observations have unveiled the population of merging black holes and neutron stars, providing direct access to strong-field gravity and dense nuclear matter. These compact binaries emit gravitational radiation as they inspiral and merge, producing waveforms that encode: the masses and spins of the constituents, neutron star's equation of state, the properties of gravity in extreme regimes, and details of their astrophysical environments. Extracting this information requires precise theoretical predictions for comparison with observations. Next-generation detectors, both ground and space-based, are expected to observe 10^3-10^5+ cycles of a given binary merger, with potentially many thousands of events per year across disparate regimes of masses, eccentricities, etc. At this scale, numerical relativity simulations alone become computationally prohibitive, making precision analytical calculations essential.

In this talk I will present new analytical approaches to the gravitational two-body problem that combine effective field theory techniques from particle physics together with tools from General Relativity. I will discuss methods for computing the dynamics of isolated binaries at high perturbative orders, as well as methods for describing binaries embedded in gaseous or dark matter environments where environmental effects modify the orbital evolution and gravitational wave signal.

Quantum guessing games provide a framework for analyzing how information encoded in quantum states can be optimally extracted through measurement. Beyond the standard role of side information, we introduce the concept of metainformation: knowledge that further side information of a certain type will later become available, even if it is not yet revealed. This distinction uncovers a finer structure in the interplay between timing, information, and strategy, and shows that metainformation can, in some scenarios, raise success probabilities to match those achievable with prior side information. Metainformation connects directly to two applications: the detection of quantum incompatibility and parallel hybrid computation. This talk outlines the basic framework of metainformation and reviews these applications.