Claims of a low clustering amplitude (S_8) at low redshifts from weak galaxy lensing measurements trace back nearly a decade, however, recent work suggests these results may be driven by large baryonic feedback or mischaracterization of linear alignments. I will present a complimentary approach to measure the evolution of S_8(z) using spectroscopically calibrated DESI galaxies and the latest CMB lensing measurements from Planck and ACT. These data are insensitive to many of the systematic complications present in galaxy lensing measurements, while our fiducial Hybrid Effective Field Theory model robustly regulates the information obtainable from smaller scales, such that our cosmological constraints are reliably derived from the (predominantly) linear regime. Our tomographic analysis of DESI Luminous Red Galaxies (LRG) prefers a slightly lower (5 − 7%) value of S_8 than primary CMB measurements with a statistical significance ranging from 1.8 − 2.3σ. Intriguingly, our lowest redshift LRG bin is most discrepant with a Planck cosmology, leaving open the possibility that structure growth is slowing down for redshifts z < 0.5. To address this possibility, I will conclude my talk with preliminary results from the DESI Bright Galaxy Survey, which enable tomographic S_8(z) measurements over the redshift range 0.1 \lesssim z \lesssim 0.4.
I will discuss free (i.e., noninteracting) and interacting classifications for certain fermionic symmetry-protected topological phases (SPTs) and show how to define free-to-interacting maps in terms of homotopy theory. I will apply these ideas to study the phenomenon of the "Bott spiral": as shown in work of Queiroz-Khalaf-Stern using a dimensional reduction approach, the tenfold way classification of free theories (with one additional reflection symmetry) breaks down to a large 2-torsion classification in the presence of interactions. Using K-theory and (Anderson-dual) twisted spin bordism, we can compute the same interacting classification, and with the language of fermionic groups, we can interpret the "spiral" as a failure of Morita invariance on the interacting side. Time permitting, I will also discuss how to model dimensional reduction and symmetry breaking for the Bott spiral in terms of homotopy theory.
This talk is based on upcoming work joint with Arun Debray, Natalia Pacheco-Tallaj, and Luuk Stehouwer.
I will review the topic of primordial inflation, covering both the basics of the field and some more advanced topics. The advanced topics will be: initial conditions for inflation, slow-roll eternal inflation and the EFT of inflation.
I will review the topic of primordial inflation, covering both the basics of the field and some more advanced topics. The advanced topics will be: initial conditions for inflation, slow-roll eternal inflation and the EFT of inflation.
The 2nd talk of a monthly webinar series jointly hosted by Perimeter, IVADO, and Institut Courtois.
Speaker: David Kremer Garcia, AI Engineer & Lead Data Scientist, IBM Quantum, Yorktown Heights, NY, USA.
In this session, I will talk about how we are using AI to improve quantum circuit transpiling and optimization. I will show some of our recent work, where we apply AI methods such as Reinforcement Learning to different transpiling tasks and achieve a remarkable balance between speed and quality of the results. I will also talk about how we integrate these methods with other heuristics to provide "ai-enhanced transpiling" through our Qiskit Transpiler Service.