Department Colloquia

The Physics Department Colloquia are held at 11:30 am Tuesdays in Gzang 122.

Fall 2023

Berko Symposium

September 5, 2023

Sagar Addepalli:  Searching for New Physics in the Higgs sector 

Abstract: Between 2015 and 2018, the ATLAS experiment at the LHC recorded proton-proton collision data at an unprecedented center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 139 fb-1. This large dataset allows us to study the Higgs boson’s properties with much higher precision than ever before, opening up the hunt for inconsistencies between the Standard Model predictions and measurements. In this talk, I will present our latest measurement of the cross section of Higgs bosons produced via vector boson fusion and reconstructed in final states containing two W bosons. Despite the distinct signature typical of this final state and the relatively high production rate, many other processes lead to the same final state, making it challenging to isolate the signal. We use cutting-edge machine learning-based methods to enhance the precision on our measurements while ensuring low model dependencies, which is imperative for robust interpretation of these results. The interpretation of this measurement in the framework of Effective Field Theories allows us to set constraints on anomalous couplings of the Higgs boson.

Saptorshi Ghosh: Optimal control of bulk active fluids

Abstract: Being intrinsically non-equilibrium, active materials have the ability to perform functions that would be thermodynamically forbidden in passive materials. However, active systems exhibit diverse local attractors that correspond to distinct dynamical states, many of which exhibit chaotic turbulent-like dynamics. Designing such a system to choose a specific dynamical state to perform a desired function is a formidable challenge. Motivated by recent advances enabling optogenetic control of experimental active materials, we use optimal control theory to identify spatiotemporal sequences of light-generated activity that direct the dynamics of active matter towards a predetermined steady-state. We put this framework to the test in two scenarios: a dry polar fluid that forms asters and propagating stripes, and a wet nematic fluid whose natural dynamics are chaotic and mediated by defect motion. The findings in these studies offer a roadmap, showcasing how optimal control methods can be harnessed to craft structure, dynamics, and function across a wide spectrum of active materials.

Enabling New Discoveries: Designing and building new detectors for the High-Luminosity LHC

September 19, 2023

Gabriella Sciolla, Brandeis University

AbstractIn ten years of operation, the Large Hadron Collider (LHC) has made major strides in our understanding of Particle Physics: the Higgs boson was discovered and its properties have been measured. So far, all measurements point toward yet another confirmation of the Standard Model of Particle Physics. However, we know that New Physics beyond the Standard Model must exist. The High-Energy Physics community is gearing up to upgrade both the LHC accelerator and detectors to boost our sensitivity to New Physics in what is known as the High-Luminosity LHC (HL-LHC) program.

In this talk I will summarize what motivates this upgrade, how we are designing new detectors to meet the challenges presented by a high-luminosity collider, and what physics the HL-LHC will unlock.


October 3, 2023

Brandeis 75th Anniversity Alumni Speaker

Netta Engelhardt, MIT


Physics and the Origins of Life

October 17, 2023

Robijn Bruinsma, UCLA

Abstract: The self-assembly of closed membranes and the self-replication of nucleic acids play a central role in current attempts to recreate the earliest living systems. The colloquium will discuss experiments that highlight aspects of the assembly, growth and division of proto-cells under laboratory conditions and the physical mechanisms that are involved. A focus of the colloquium will be on the question how proto-cells could capture free energy from the environment to power these processes.


October 31, 2023

Ken Olum, Tufts University

November 14, 2023

Lydia Bourouiba, MIT


November 28, 2023

Luca Comisso, Columbia University