Search Talks

With the completion of the Planck satellite, in order to continue collecting cosmological information it is
important to gain a precise understanding of the formation of Large Scale Structures (LSS) of the universe.
The Effective Field Theory of LSS (EFTofLSS) offers a consistent theoretical framework that aims to develop
an analytic understanding of LSS at long distances, where inhomogeneities are small. We present the recent
developments in the field covering topics of biased tracers in the EFTofLSS including the effects of baryonic
physics and primordial non-Gaussianities, finding that new bias coefficients are required. We discuss the EFT
framework for dark matter clustering in Lagrangian formalism and present its consequences on baryon acoustic
oscillations (BAO). We present analytic results and compare them with the output of N-body simulations.

The iron chalcogenide FeSe has attracted much recent interest due to a high superconducting transition in monolayer samples. In bulk samples, nematic order is seen without the presence of magnetic order, hinting at the importance of nematic order in determining the monolayer properties. More generally, there has been growing evidence of the importance of nematic fluctuations in a variety of strongly correlated high-temperature superconductors. We study an effective two band model of the iron-pnictides with interactions that capture the nematic ordering arising from spontaneous symmetry breaking between the two orbitals. These models are sign-problem free and can be simulated in an unbiased fashion using Determinant Quantum Monte Carlo. We find a variety of unexpected orders and consider the effects of the nematic fluctuations on superconductivity. 

In quantum gravity, observables must be diffeomorphism-invariant. Such observables are nonlocal, in contrast with the standard assumption of locality in flat spacetime quantum field theory. I will show how to construct 'gravitationally dressed' observables in linearized gravity that become local in the weak gravity limit, and whose corrections to exact locality are characterized by the Newtonian potential. One can attempt to make these observables more local by concentrating gravitational field lines into a smaller solid angle. In AdS_3 gravity I will show that nonperturbatively there are sharp limits to how much the gravitational dressing can be concentrated.

Based on arXiv:1507.07921 with Steve Giddings, and arXiv:1510.00672 with Don Marolf and Eric Mintun.