The AdS/CFT correspondence maps correlators of local operators in a conformal field theory to scattering amplitudes in a gravitational/string theory on curved space-time. The study of such amplitudes is incredibly hard and has mostly been done in a certain classical limit. We show how modern analytic bootstrap techniques allow us to go much...

# Events Archive

## Events Archive

### Hamilton Colloquium Series, Luis Fernando Alday, Oxford University, "Quantum Scattering Amplitudes in AdS/CFT"

### SMuRF/Daq User Interface Meeting | 2nd Edition, JH room

**09:00 - 09:30**: Light Breakfast

### Condensed Matter Seminar | Helen Bouchiat, U of Paris Sud | "Revealing the second-order topological character of bismuth-based Josephson junction" | Joseph Henry Room

In Second-Order Topological Insulators (SOTI), bulk and surfaces are insulating while the edges or hinges conduct current in a quasi-ideal (ballistic) way, being insensitive to disorder. Crystalline bismuth has been shown to belong to this class of materials [1,2,3].

### Pheno & Vino Seminar | Christoph Weniger, U of Amsterdam | "Uncovering Dark Matter with Compact Objects and Automatic Differentiation" | Jadwin 303

The nature of dark matter (DM) in the Universe remains one of the great open questions of particle astrophysics and cosmology today. The WIMP (weakly interacting massive particle) DM paradigm has fallen, leaving us with a wide range of possible DM models and signatures. New methods and ideas are required to efficiently progress.

### The quantum sounds of electrons and the quantum noise of spinons - Inti Sodemann - Max Planck

The problem of strongly interacting gapless fermions above one dimension is one of the wildest open frontiers in quantum condensed matter where our understanding remains insular and embedded in vast oceans of mystery.

### Real-space approach for topological states and a new principle of bulk-boundary correspondence - Zhida Song

Abstract: The real-space approach has been proved as a powerful method to study topological states: both the classification of topological states and that of their anomalous surfaces can be obtained in an intuitive, straightforward way. I will talk about new progress in topological materials which is inspired by, the real-space approach.

### Gravity Initiative Lunch, Bart Ripperda | Princeton/Flatiron "Magnetic reconnection and plasmoid formation in black hole accretion flows"

Hot spots, or plasmoids, formed due to magnetic reconnection in thin current sheets are conjectured to power frequent bright X-ray and near-infrared flares from supermassive black holes, like Sgr A* in the center of our Galaxy.

### Cancelled. To Be Rescheduled. Biophysics Seminar: Stephanie Palmer, University of Chicago: How behavioral and evolutionary constraints sculpt early visual processing|Joseph Henry Room

While efficient coding has been a successful organizational principle in visual neuroscience, to make a more general theory behavioral, mechanistic, and even evolutionary constraints need to be added to this framework.

### Hamilton Colloquium Series, Ricard Alert, Princeton University, "The Physics of Collective Cell Migration"

Cells in our body move in groups during development, wound healing, and tumor spreading. Bacterial cells also coordinate their motion to aggregate into biofilms, to feed cooperatively, and to form fruiting bodies.

### Mathematical Physics Seminar: Charles Newman, Courant Institute, "A Gaussian Process Related to the Mass Spectrum of the Near-Critical Ising Model"

The continuum scaling limit of the Ising model in d dimensions at the critical temperature whose magnetic field properly scales to zero with lattice spacing is (or should be) a non-Gaussian generalized random field Phi for d = 2 (and d = 3).

### Pheno & Vino Seminar | William Terrano, Princeton | "Direct Detection Searches for Fuzzy Dark Matter and Ultra Low Mass Axions at Princeton" | Jadwin 303

I will discuss experimental prospects for directly detecting ultra-low-mass dark matter, including the interesting “Fuzzy” dark matter scenario. I will describe experiments which are ongoing here at Princeton, and the challenges associated with them. I will also present the results we have thus far, and the prospects for future improvements...

### Title: Many Body Effects of Chiral Edge Fermions - Biao Lian - Princeton

1+1D Chiral Fermions on the edges of 2+1D chiral topological phases are free from backscattering, which lead to quantized Hall and thermal Hall effects. Interacting chiral fermions at low energies are usually believed to form an integrable chiral Luttinger liquid. We study the integrability of N identical chiral Majorana fermion modes with...

### Dark Matter in the Era of Gaia - Lina Necib - Caltech

The Gaia mission has provided distance and velocity measurements of over a billion stars in the Milky Way, making it the largest stellar catalog at hand. Simultaneously, recent developments in cosmological simulations have made it possible to track stars and dark matter in realistic Milky Way-like galaxies.

### HET Seminar | Walter Goldberger, Yale University | "An Effective Field of Theory of Quantum Black Hole Horizons" | Bloomberg Lecture Hall, IAS | 2:30pm

I develop an effective theory which describes black holes with quantum mechanical horizons that is valid at scales long compared to the Schwarzschild radius but short compared to the lifetime of the black hole. The formalism allows one to calculate the quantum mechanical effects in scattering processes involving black hole asymptotic states.

### Gravity Initiative Lunch, Katerina Chatziioannou | CCA "Studying neutron stars with gravitational waves"

Neutron stars, the most dense astrophysical bodies we know of, are at the heart of many interesting astrophysical phenomena from their birth in supernova explosions to their deaths in collisions with other dense objects.

### Biophysics Seminar: Elizabeth Jerison, Stanford University: Dynamics of adaptive immunity in zebrafish| Joseph Henry Room

The immune responses that defend us against pathogens are driven by stochastic processes amongst populations of cells. Enormous progress in immunology over the last few decades has identified most of the components of this complex system, including the cell types and the molecules used for communication.

### HET Seminar | Atish Dabholkar, Abdus Salam ICTP, Trieste | "Three Avatars of Mock Modularity" | PCTS, Jadwin 407

Mock theta functions were introduced by Ramanujan in his famous last letter to Hardy in 1920 but were properly understood only recently with the work of Zwegers in 2002.

### Gravity Group Lunch Seminar, Ivan Padilla | JHU "Cosmology Large Angular Scale Surveyor: Circular polarization at 40 GHz"

Large angular scale polarimetry of the CMB will provide powerful constraints on the cosmological parameters r, the tensor-to-scalar ratio, and tau, the optical depth to the epoch of reionization.

### Pheno & Vino Seminar | Cara Giovanetti, Princeton | "Dynamical Friction in a Fuzzy Dark Matter Universe" | Jadwin Hall

Fuzzy Dark Matter (FDM) is a model of dark matter consisting of an ultralight scalar whose quantum mechanical nature is manifest at kiloparsec scales. As such, an object moving through an FDM halo will experience a different drag force due to dynamical friction than an object passing through a classical dark matter halo. This effect is...