Center for Mathematical Sciences Research
Christopher Jarzynski – University of Maryland
Wednesday, July 29, 2026
Zoom opens: 10:30AM EDT
Seminar begins: 10:45AM EDT
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Estimating free energy differences with virtually escorted trajectories
The convergence of numerical free energy estimation methods can be accelerated using artificial fields that “escort” simulated trajectories along near-equilibrium paths. Unfortunately, designing such fields is not easy. Taking a cue from the mathematics behind diffusion models – a class of generative models in machine learning – we introduce a method based on virtual escorting. This method adopts a post-processing approach. Given a fixed set of nonequilibrium trajectories, a parameter-dependent virtual escorting field is constructed, possibly using a neural network. This field is used in combination with the trajectories to produce an estimate of the desired free energy difference. The parameters are then adjusted to optimize the convergence of the estimate. I will describe the method, and will discuss conditions under which it produces a zero-variance estimator of the free energy difference.
Uri Alon - Weizmann Institute
Wednesday, July 22, 2026
Why is the upper tail of human lifespan so rigid? Insights from Langevin threshold-crossing models of aging
Human life expectancy has doubled over the last two centuries, yet the upper tail of human lifespan has barely moved. Why is median lifespan so plastic while extreme longevity remains so rigid? I will present a stochastic threshold-crossing view of aging, in which physiological damage follows time-dependent Langevin dynamics and death occurs as a first-passage event across a critical threshold. In this framework, the exponential increase in mortality with age corresponds to escape from a linearly declining barrier. The model separates two classes of parameters: **robustness parameters**, such as noise amplitude and threshold height, which affect the probability of crossing the barrier, and **senogenic parameters**, which govern the deterministic damage production and removal. Changes in robustness can improve median survival while preserving extreme-lifespan distributions, whereas changes in senogenic parameters shift extreme longevity. I will discuss how this distinction helps interpret historical mortality improvements, lifestyle and socioeconomic effects, which all seem to only affect robustness parameters, as well as familial longevity, and progeroid diseases.
Larry Abbott - Columbia University
Wednesday, July 15, 2026
Biological Systems for Spatial Orientation
I will discuss several topics related to how animals represent and update their sense of orientation in the world. In flies, this is done with a set of neurons that collectively form a ring-attractor network. Activity in this system indicates the azimuthal orientation of the fly. I will discuss how the polarization pattern of the sky is used as keep this encoded angle aligned with the physical world. Vertebrates have an analogous system for head orientation, but it is more complex. I will discuss various ways that a ring-attractor could be embedded in a large population of neurons, with results relevant for studies of the synaptic connections in these circuits. Finally, in both flies and vertebrates, these systems have been studied primarily in two dimension (that is, considering only yaw rotations). I will discuss different ideas about how they might respond to three-dimensional rotations.
Itamar Procaccia - Weizmann Insitute Wednesday, July 8, 2026 Zoom opens: 10:30AM EDT Seminar begins: 10:45AM EDT Amorphous Solids: More than Meets the Eye Understanding the mechanical response of amorphous solids, like glasses and granular media, requires considerations that go
Michael Shelley - Flatiron Institute & NYU Wednesday, July 1, 2026 Zoom opens: 10:30AM EDT Seminar begins: 10:45AM EDT Modeling chromatin as an active polymer melt In this talk I'll discuss a line of work wherein chromatin in the nucleus
Robert McCann – University of Toronto Wednesday, June 24, 2026 Zoom opens: 10:30AM EDT Seminar begins: 10:45AM EDT Trading linearity for ellipticity: a low regularity Lorentzian splitting theorem While Einstein's theory of gravity is formulated in a smooth setting, the
Doyne Farmer – Oxford University Wednesday, June 17, 2026 Zoom opens: 10:30AM EDT Seminar begins: 10:45AM EDT Quantitative complexity economics: A revolution in the making Mainstream economic theory follows a standard template that I will review in this talk. Complexity
130th Statistical Mechanics Conference Sunday May 10 2026 - Tuesday May 12 2026 at 0800am - 0500pm nbspHill Center 100 Frelinghuysen Road Room 116 Piscataway NJ nbsp Celebrating the achievements of our guests of honor Michael Loss Marc Mzardnbsp Subir
