Wednesday, October 8th, 2025
YITP Event: Seminar Speaker: Rotem Ovadia- Hebrew University
Time: 11:00 AM - 12:00 PM
Location:
Title: Determining (All) Dark Matter--Electron Scattering Rates From Material Properties
Abstract: We show that the scattering rate for any dark matter (DM) interaction with electrons in any target is proportional to several measurable material properties, encapsulated by a single master formula. This generalizes the dielectric function formalism---developed for DM interactions that couple to electron density---to any interaction, incorporating both spin-dependent and spin-independent interactions simultaneously. This formalism links the full many-body response of a target system to the DM probe in a clear and simple form, providing a reliable event rate prediction from measurable material quantities. We demonstrate the utility of our  formalism by placing new limits from existing data on a class of spin-dependent light DM interactions,  as their rates---contrary to common lore---are determined entirely by the dielectric function. We further highlight a promising avenue for the detection of sub-MeV DM using the rare earth metal Praseodymium, which exhibits a spin-dependent anisotropic response down to the ${\rm meV}$ scale. Our results lay the groundwork for a rapid systematic investigation of novel electron scattering targets going beyond the classic spin-independent searches, enhancing the prospects for DM detection.
Title: Determining (All) Dark Matter--Electron Scattering Rates From Material Properties
Abstract: We show that the scattering rate for any dark matter (DM) interaction with electrons in any target is proportional to several measurable material properties, encapsulated by a single master formula. This generalizes the dielectric function formalism---developed for DM interactions that couple to electron density---to any interaction, incorporating both spin-dependent and spin-independent interactions simultaneously. This formalism links the full many-body response of a target system to the DM probe in a clear and simple form, providing a reliable event rate prediction from measurable material quantities. We demonstrate the utility of our  formalism by placing new limits from existing data on a class of spin-dependent light DM interactions,  as their rates---contrary to common lore---are determined entirely by the dielectric function. We further highlight a promising avenue for the detection of sub-MeV DM using the rare earth metal Praseodymium, which exhibits a spin-dependent anisotropic response down to the ${\rm meV}$ scale. Our results lay the groundwork for a rapid systematic investigation of novel electron scattering targets going beyond the classic spin-independent searches, enhancing the prospects for DM detection.
Physics Seminar: Oleksander Diatlyk
Time: 2:00 PM - 3:00 PM
Location: 313
Title: Effective Field Theory of Conformal Boundaries  Â
Abstract: We introduce an effective field theory (EFT) for conformal impurity by considering a pair of transversely displaced impurities and integrating out modes with mass inversely proportional to the separation distance. This EFT captures the universal signature of the impurity seen by a heavy local operator. We focus on the case of conformal boundaries and derive universal formulas from this EFT for the boundary structure constants at high energy. We point out that the more familiar thermal EFT for conformal field theory is a special case of this EFT with distinguished conformal boundaries. We also derive, for general conformal impurities, nonpositivity and convexitylike constraints on the Casimir energy which determines the leading EFT coefficient.
Title: Effective Field Theory of Conformal Boundaries  Â
Abstract: We introduce an effective field theory (EFT) for conformal impurity by considering a pair of transversely displaced impurities and integrating out modes with mass inversely proportional to the separation distance. This EFT captures the universal signature of the impurity seen by a heavy local operator. We focus on the case of conformal boundaries and derive universal formulas from this EFT for the boundary structure constants at high energy. We point out that the more familiar thermal EFT for conformal field theory is a special case of this EFT with distinguished conformal boundaries. We also derive, for general conformal impurities, nonpositivity and convexitylike constraints on the Casimir energy which determines the leading EFT coefficient.
Thursday, October 9th, 2025
100 Year of Quantum Mechanics Exhibition Opening Reception
Time: 4:30 PM - 6:00 PM
Location: Simons Center Lobby, Gallery and Room 103
Title: God Plays Dice with the World: The Story of Quantum Mechanics Della Pietra Family Auditorium, SCGP 103
Abstract: What is matter? A question that has fascinated—and at times tormented—some of the brightest minds of the twentieth century. Max Planck, Albert Einstein, Niels Bohr, Erwin Schrödinger, Werner Heisenberg, Max Born, Wolfgang Pauli, and Paul Dirac all grappled with it, debating fiercely, colliding over equations and experiments, in their attempt to decipher the very essence of physical reality. Out of this intellectual struggle was born quantum mechanics, a theory that unveils a microscopic universe ruled by probability—an outcome that Einstein found so unsettling that he refused to accept its philosophical implications. A century after its first complete formulation, in the seminar we retrace the history of this scientific revolution through its protagonists and its places: from the hushed courtyards of Cambridge colleges to the windswept cliffs of Helgoland, amid biographies worthy of an adventure novel and exchanges of fiery letters. The result is a captivating narrative that pays tribute to an unrepeatable season in the history of science.
Title: God Plays Dice with the World: The Story of Quantum Mechanics Della Pietra Family Auditorium, SCGP 103
Abstract: What is matter? A question that has fascinated—and at times tormented—some of the brightest minds of the twentieth century. Max Planck, Albert Einstein, Niels Bohr, Erwin Schrödinger, Werner Heisenberg, Max Born, Wolfgang Pauli, and Paul Dirac all grappled with it, debating fiercely, colliding over equations and experiments, in their attempt to decipher the very essence of physical reality. Out of this intellectual struggle was born quantum mechanics, a theory that unveils a microscopic universe ruled by probability—an outcome that Einstein found so unsettling that he refused to accept its philosophical implications. A century after its first complete formulation, in the seminar we retrace the history of this scientific revolution through its protagonists and its places: from the hushed courtyards of Cambridge colleges to the windswept cliffs of Helgoland, amid biographies worthy of an adventure novel and exchanges of fiery letters. The result is a captivating narrative that pays tribute to an unrepeatable season in the history of science.
Friday, October 10th, 2025
Probability Day Mini-Conference: Talk by Mehtaab Sawhney
Time: 11:00 AM - 12:00 PM
Location: 102
Title: Hitting time mixing for the random transposition walk
Speaker: Mehtaab Sawhney
Abstract: Consider shuffling a deck of n cards, labeled 1 through n, as follows: at each time step, pick one card uniformly with your right hand and another card, independently and uniformly with your left hand; then swap the cards. How long does it take until the deck is close to random? Confirming a conjecture of N. Berestycki, we prove the definitive "hitting time" version for the mixing of this shuffle. Let τ denote the first time at which all cards have been touched. The total variation distance between the stopped distribution at τ and the uniform distribution on permutations is o_n(1); this is best possible, since at time τ−1, the total variation distance is at least (1+o_n(1))/e. A key feature of this proof is to combine the representation theoretic inputs of Diaconis and Shahshahani with a physical space argument. Based on joint work w. Vishesh Jain.
Title: Hitting time mixing for the random transposition walk
Speaker: Mehtaab Sawhney
Abstract: Consider shuffling a deck of n cards, labeled 1 through n, as follows: at each time step, pick one card uniformly with your right hand and another card, independently and uniformly with your left hand; then swap the cards. How long does it take until the deck is close to random? Confirming a conjecture of N. Berestycki, we prove the definitive "hitting time" version for the mixing of this shuffle. Let τ denote the first time at which all cards have been touched. The total variation distance between the stopped distribution at τ and the uniform distribution on permutations is o_n(1); this is best possible, since at time τ−1, the total variation distance is at least (1+o_n(1))/e. A key feature of this proof is to combine the representation theoretic inputs of Diaconis and Shahshahani with a physical space argument. Based on joint work w. Vishesh Jain.
Probability Day Mini-Conference: Talk by Amanda Priestley
Time: 1:00 PM - 1:30 PM
Location: 102
Title: Probability and Parking
Speaker: Amanda Priestley
Abstract: In 1966, Konheim and Weiss introduced a deterministic model of parking and a related family of combinatorial objects called parking functions. While there are extensive enumerative results on parking functions, much less is known from a probabilistic perspective. In this talk, I will discuss three key probabilistic frameworks that have been applied to these objects and present our contributions within each.
Title: Probability and Parking
Speaker: Amanda Priestley
Abstract: In 1966, Konheim and Weiss introduced a deterministic model of parking and a related family of combinatorial objects called parking functions. While there are extensive enumerative results on parking functions, much less is known from a probabilistic perspective. In this talk, I will discuss three key probabilistic frameworks that have been applied to these objects and present our contributions within each.
Probability Day Mini-Conference: Talk by Eyob Tsegaye
Time: 1:30 PM - 2:00 PM
Location: 102
Title: Limit Profile for the Mixing Time of the TASEP in the High and Low Density Phase
Speaker: Eyob Tsegaye
Abstract: The totally asymmetric simple exclusion process is a widely studied interacting particle system where particles hop to the right on a line according to independent rate 1 Poisson clocks, with the constraint that two particles cannot occupy the same space. We consider this process on a finite line segment of length N with open boundaries, so that particles can also enter from the left boundary and exit from the right. It was previously shown by Elboim and Schmid that under high and low density conditions, this process rapidly changes from unmixed to mixed in a critical time window around CN, where C is an explicit constant – the so-called cutoff phenomenon. We refine this statement to show the exact decay of the total variation distance within the critical time window. Along the way, we obtain an enlightening picture of how the process gradually mixes. This is based on ongoing work with Dominik Schmid.
Title: Limit Profile for the Mixing Time of the TASEP in the High and Low Density Phase
Speaker: Eyob Tsegaye
Abstract: The totally asymmetric simple exclusion process is a widely studied interacting particle system where particles hop to the right on a line according to independent rate 1 Poisson clocks, with the constraint that two particles cannot occupy the same space. We consider this process on a finite line segment of length N with open boundaries, so that particles can also enter from the left boundary and exit from the right. It was previously shown by Elboim and Schmid that under high and low density conditions, this process rapidly changes from unmixed to mixed in a critical time window around CN, where C is an explicit constant – the so-called cutoff phenomenon. We refine this statement to show the exact decay of the total variation distance within the critical time window. Along the way, we obtain an enlightening picture of how the process gradually mixes. This is based on ongoing work with Dominik Schmid.
Probability Day Mini-Conference: Talk by Zongrui Yang
Time: 2:00 PM - 2:30 PM
Location: 102
Title: Stationary measures for integrable models with open boundaries
Speaker: Zongrui Yang
Abstract: In this talk, I will discuss methods for studying the stationary measures of integrable models with open boundaries, with a particular focus on the open asymmetric simple exclusion process (ASEP). The approaches I will present draw on the matrix product ansatz, two-layer Gibbs measures, and Askey–Wilson orthogonal polynomials.
Title: Stationary measures for integrable models with open boundaries
Speaker: Zongrui Yang
Abstract: In this talk, I will discuss methods for studying the stationary measures of integrable models with open boundaries, with a particular focus on the open asymmetric simple exclusion process (ASEP). The approaches I will present draw on the matrix product ansatz, two-layer Gibbs measures, and Askey–Wilson orthogonal polynomials.