Mon 22 Apr 16:00: Automatic Outlier Rectification via Optimal Transport TMLW02 - SGD: stability, momentum acceleration and heavy tails
TMLW02 - SGD: stability, momentum acceleration and heavy tails
- Speaker: Jose Blanchet (Stanford University)
- Monday 22 April 2024, 16:00-16:45
- Venue: External.
- Series: Isaac Newton Institute Seminar Series; organiser: nobody.
Mon 22 Apr 11:00: Simulation and inference for Levy-driven SDEs TMLW02 - SGD: stability, momentum acceleration and heavy tails
TMLW02 - SGD: stability, momentum acceleration and heavy tails
- Speaker: Simon Godsill (University of Cambridge)
- Monday 22 April 2024, 11:00-11:45
- Venue: External.
- Series: Isaac Newton Institute Seminar Series; organiser: nobody.
Mon 22 Apr 09:45: Exit Times and Extremes of Fractional Brownian motion and Spectrally Negative Levy Processes TMLW02 - SGD: stability, momentum acceleration and heavy tails
Inspired by many applications, especially in Financial Mathematics and Heavy Tail Phenomena, this talk will begin with providing some old and improved bounds on the first hitting times of fractional Brownian motion and its draw-down process. Asymptotically, the tail of distribution of the first hitting time of drawdown/loss/regret process over [0, t] behaves like the tail of the marginal distribution at time t. Next, our focus will be on the two-sided exit times of draw-down and draw-up processes of spectrally negative Levy processes. Finally, the Laplace transform of the “three-sided” exit times of spectrally negative Levy and its draw-down process from a rectangular region will be demostrated together with the Laplace transforms of these exit-times out of a Trapezoid.
TMLW02 - SGD: stability, momentum acceleration and heavy tails
- Speaker: Ceren Vardar Acar (Middle East Technical University)
- Monday 22 April 2024, 09:45-10:30
- Venue: External.
- Series: Isaac Newton Institute Seminar Series; organiser: nobody.
Fri 26 Apr 14:00: title and abstract tba EMG - New equivariant methods in algebraic and differential geometry
EMG - New equivariant methods in algebraic and differential geometry
- Speaker: Barbara Fantechi (SISSA)
- Friday 26 April 2024, 14:00-15:00
- Venue: Seminar Room 1, Newton Institute.
- Series: Isaac Newton Institute Seminar Series; organiser: nobody.
Wed 24 Jul 16:00: Clay Math Public Lecture: Title TBC SSD - Stochastic systems for anomalous diffusion
SSD - Stochastic systems for anomalous diffusion
- Speaker: Gordon Slade (University of British Columbia)
- Wednesday 24 July 2024, 16:00-17:00
- Venue: Seminar Room 1, Newton Institute.
- Series: Isaac Newton Institute Seminar Series; organiser: nobody.
Wed 15 May 11:45: Partial Okounkov bodies and toric geometry EMGW04 - K-stability and moment maps
Given a big line bundle L on a projective manifold, Lazarsfeld–Mustată and Kaveh–Khovanskii introduced method of constructing convex bodies associated with L. These convex bodies are known as Okounkov bodies. When L is endowed with a singular positive Hermitian metric h, I will explain how to construct smaller convex bodies from the data (L,h). These convex bodies play important roles in the study of the singularities of h. As an application, I will explain a non-trivial application in toric geometry due to Yi Yao.
EMGW04 - K-stability and moment maps
- Speaker: Mingchen Xia (Institut de Mathématiques de Jussieu)
- Wednesday 15 May 2024, 11:45-12:45
- Venue: Seminar Room 1, Newton Institute.
- Series: Isaac Newton Institute Seminar Series; organiser: nobody.
Thu 23 May 17:00: Title to be confirmed
Abstract not available
- Speaker: Georges Gonthier
- Thursday 23 May 2024, 17:00-18:00
- Venue: Live-streamed at MR14 Centre for Mathematical Sciences.
- Series: Formalisation of mathematics with interactive theorem provers ; organiser: Jonas Bayer.
Thu 09 May 17:00: Title to be confirmed
Abstract not available
- Speaker: Tomas Skrivan (Carnegie Mellon University)
- Thursday 09 May 2024, 17:00-18:00
- Venue: Live-streamed at MR14 Centre for Mathematical Sciences.
- Series: Formalisation of mathematics with interactive theorem provers ; organiser: Jonas Bayer.
Thu 13 Jun 17:00: Alpha-Beta Pruning Explored, Extended and Verified
Alpha-beta pruning is an efficient search strategy for two-player game trees. It was invented in the late 1950s and is at the heart of most implementations of combinatorial game playing programs. In this talk I will survey my recent formalizations and verifications of a number of standard variations of alpha-beta pruning. Findings include:
- Basic variants already having a property ascribed to an improved version
- Authors being confused about which algebraic structure they actually work in
- Generalizations to new algebraic structures
- The implementation in a famous paper is flawed
- Speaker: Professor Tobias Nipkow (Technische Universität München)
- Thursday 13 June 2024, 17:00-18:00
- Venue: Live-streamed at MR14 Centre for Mathematical Sciences.
- Series: Formalisation of mathematics with interactive theorem provers ; organiser: Anand Rao Tadipatri.
Thu 16 May 17:00: Teaching using a proof assistant and controlled natural language
Abstract not available
- Speaker: Professor Patrick Massot (Université Paris-Saclay and Carnegie Mellon University)
- Thursday 16 May 2024, 17:00-18:00
- Venue: Live-streamed at MR14 Centre for Mathematical Sciences.
- Series: Formalisation of mathematics with interactive theorem provers ; organiser: Anand Rao Tadipatri.
Thu 02 May 17:00: Condensed Type Theory
Condensed sets form a topos, and hence admit an internal type theory. In this talk I will describe a list of axioms satisfied by this particular type theory. In particular, we will see two predicates on types, that single out a class CHaus of “compact Hausdorff” types and a class ODisc of “overt and discrete” types, respectively. A handful of axioms describe how these classes interact. The resulting type theory is spiritually related Taylor’s “Abstract Stone Duality”.
As an application I will explain that ODisc is naturally a category, and furthermore, every function ODisc → ODisc is automatically functorial. This axiomatic approach to condensed sets, including the functoriality result, are formalized in Lean 4. If time permits, I will comment on some of the techniques that go into the proof.
Joint work with Reid Barton.
- Speaker: Dr Johan Commelin (Utrecht University)
- Thursday 02 May 2024, 17:00-18:00
- Venue: Live-streamed at MR14 Centre for Mathematical Sciences.
- Series: Formalisation of mathematics with interactive theorem provers ; organiser: Jonas Bayer.
Thu 25 Apr 14:00: Resonant Bloch oscillations in transmons embedded in high-impedance circuits
Superconducting circuits offers a unique setting to explore the strong-coupling counterpart to standard electrodynamics, with which a variety of quantum devices can be realized. A prerequisite for such strong coupling is a medium with very high characteristic impedance, which can be achieved by recently developed Josephson junction array transmission lines, dubbed “super-inductors”. These provide both the high impedance needed for strong quantum fluctuations, and photon modes with which to probe a quantum device, such as a small Josephson junction – i.e. a superconducting qubit. In this high-impedance environment, current through the junction is suppressed by Coulomb blockade, and is accompanied by Bloch oscillations analogous to those in crystalline systems. However, the interplay between Bloch oscillations and environmental photon resonances remains largely unexplored. In this talk I will give a brief introduction to circuit electrodynamics, superconducting qubits, and the superconductor-insulator transition. Then I will develop a model for Bloch oscillations in a transmon-type qubit placed in a high-impedance cavity [1]. The latter’s discrete spectrum will cause resonances in the voltage–current relation and the spectrum of photons radiated by the transmon. The transmon also scatters cavity photons inelastically; I will show a novel anti-Stokes-like process whereby photons gain a Bloch oscillation quantum. These signatures show how Bloch oscillations leave fingerprints across disparate energy scales. Time permitting, I will discuss how such Bloch oscillations give rise to dual-Shapiro steps, with applications to quantum metrology [2].
[1] B. Remez, V. D. Kurilovich, M. Rieger, and L. I. Glazman, Bloch Oscillations in a Transmon Embedded in a Resonant Electromagnetic Environment, arXiv:2403.04623.
[2] V. D. Kurilovich, B. Remez, and L. I. Glazman, Quantum Theory of Bloch Oscillations in a Resistively Shunted Transmon, arXiv:2403.04624.
- Speaker: Benjamin Remez (Yale)
- Thursday 25 April 2024, 14:00-15:00
- Venue: TCM Seminar Room.
- Series: Theory of Condensed Matter; organiser: Bo Peng.
Fri 03 May 14:00: Rates of convergence for tensor denoising
See abstract here
- Speaker: Sara van de Geer, ETH Zürich
- Friday 03 May 2024, 14:00-15:00
- Venue: MR12, Centre for Mathematical Sciences.
- Series: Statistics; organiser: Dr Sergio Bacallado.
Fri 19 Apr 13:00: Dynamical Gravastars
I give new results for ``gravastars’’, which are horizonless compact objects that closely mimic mathematical black holes in their exterior geometry, but for which $g_{00}$ is always positive. In my initial formulation, they result from solving the Tolman-Oppenheimer-Volkoff (TOV) equations for relativistic stellar structure, which require continuous pressure, but with an interior density jump from a normal matter equation of state, to an equation of state where pressure plus density approximately sum to zero. We present Mathematica notebooks solving the TOV equations, in which the structure of the gravastar is entirely governed by the Einstein-Hilbert gravitational action (with zero cosmological constant) together with the matter equation of state, with radii where structural changes occur emerging from the dynamics, rather than being specified in advance as in the original Mazur-Mottola gravastars.
My more recent work with a student shows that the interesting ``simulated horizon’’ structure of dynamical gravastars is a property solely of the exterior TOV equations for relativistic matter with appropriate small radius boundary conditions, and will be present for a large class of interior equations of state. The exterior TOV equations can be rewritten in rescaling-invariant form, leading to a two dimensional autonomous system of differential equations which are now being studied numerically and analytically , and for which hopefully some rigorous results can be proved.
- Speaker: Stephen Adler, Princeton, Institute for Advanced Study
- Friday 19 April 2024, 13:00-14:00
- Venue: Potter room/Zoom: https://cam-ac-uk.zoom.us/j/85670039340?pwd=MmRxMDdYMGY5b0IzSm9QRUJmWFNVUT09.
- Series: DAMTP Friday GR Seminar; organiser: Xi Tong.
Thu 23 May 16:00: Unstable Bundles and Twisted Brill-Noether Theor EMG - New equivariant methods in algebraic and differential geometry
It is well known that one of the challenges in having algebraic varieties as moduli spaces is that the objects under consideration often have non-trivial endomorphisms. In this talk, I will show that by fixing the algebra of endomorphisms of unstable vector bundles, it becomes feasible to construct moduli spaces that are (quasi)-projective varieties. The existence of such moduli spaces is closely related to Twisted Brill-Noether Theory and Butler’s conjecture.
EMG - New equivariant methods in algebraic and differential geometry
- Speaker: Leticia Brambila-Paz (Centro de Investigación en Matemáticas)
- Thursday 23 May 2024, 16:00-17:00
- Venue: Seminar Room 2, Newton Institute.
- Series: Isaac Newton Institute Seminar Series; organiser: nobody.
Thu 13 Jun 17:00: Alpha-Beta Pruning Explored, Extended and Verified
Alpha-beta pruning is an efficient search strategy for two-player game trees. It was invented in the late 1950s and is at the heart of most implementations of combinatorial game playing programs. In this talk I will survey my recent formalizations and verifications of a number of standard variations of alpha-beta pruning. Findings include:
- Basic variants already having a property ascribed to an improved version
- Authors being confused about which algebraic structure they actually work in
- Generalizations to new algebraic structures
- The implementation in a famous paper is flawed
- Speaker: Professor Tobias Nipkow, Technische Universität München
- Thursday 13 June 2024, 17:00-18:00
- Venue: Live-streamed at MR14 Centre for Mathematical Sciences.
- Series: Formalisation of mathematics with interactive theorem provers ; organiser: Anand Rao Tadipatri.
Wed 05 Jun 16:00: Rothschild Public Lecture: Inertia, Turbulence and the Concentration Field in Active Fluids ADI - Anti-diffusive dynamics: from sub-cellular to astrophysical scales
The spectacular phenomena displayed by fluids of self-driven particles arise through the interplay of broken time-reversal symmetry with conservation laws of matter and total momentum. I will open with the transition from order to active turbulence, the end-state of the instability of aligned states of orientable motile particles, with an inertial rather than a viscous perspective. I will discuss two simplifying limits – a one-component active fluid, and a densely packed suspension – in which the active-particle concentration does not appear explicitly. I will then turn to the interaction of hydrodynamic flow and particle currents in varied settings: an obstacle in a dilute suspension, as well as phenomena in denser systems. At each stage I will highlight fundamental theoretical issues.
ADI - Anti-diffusive dynamics: from sub-cellular to astrophysical scales
- Speaker: Sriram Ramaswamy (Indian Institute of Science)
- Wednesday 05 June 2024, 16:00-17:00
- Venue: Seminar Room 1, Newton Institute.
- Series: Isaac Newton Institute Seminar Series; organiser: nobody.
Thu 16 May 17:00: Teaching using a proof assistant and controlled natural language
Abstract not available
- Speaker: Professor Patrick Massot, Université Paris-Saclay and Carnegie Mellon University
- Thursday 16 May 2024, 17:00-18:00
- Venue: Live-streamed at MR14 Centre for Mathematical Sciences.
- Series: Formalisation of mathematics with interactive theorem provers ; organiser: Anand Rao Tadipatri.
Fri 26 Apr 16:00: New physics searches at colliders using HEFT
Using the $\kappa$ framework, the constraints on the quartic interactions of Higgs with gauge bosons give a qualitative picture of consistency with the SM when the statistical yield is low. However, increasing statistics necessitates a more theoretically consistent framework to constrain such couplings. Therefore, using the framework of the non-linear Higgs Effective Field Theory (HEFT), I will talk about the radiative corrections to Higgs decays and discuss the current and future sensitivity to quartic Higgs gauge couplings using the single Higgs data. In the subsequent part of the talk, using the off-shell Higgs boson measurements in massive gauge boson pair production, I will study these processes in the context of the HEFT framework and discuss the constraints on the relevant Higgs boson non-linear interactions.
Finally, extending the HEFT leading order (LO) interactions with the axion-like particles (ALP) field, I will focus on the interactions that probe the singlet nature of Higgs. The Higgs decay phenomenology is discussed in the presence of ALP at LO. To obtain additional constraints, I will focus on the multi-top and multi-Higgs processes by modifying the Higgs two and three-point functions by considering ALP interactions beyond LO.
- Speaker: Anisha (Glasgow U.)
- Friday 26 April 2024, 16:00-17:00
- Venue: MR19 (Potter Room, Pavilion B), CMS.
- Series: HEP phenomenology joint Cavendish-DAMTP seminar; organiser: Nico Gubernari.
Fri 03 May 16:00: Froggatt-Nielsen Models Meet the SMEFT
The Froggatt-Nielsen (FN) mechanism is one of the oldest and simplest attempts at explaining the striking hierarchies observed in the fermion masses and mixings. Given that FN models give rise to the correct fermion masses and mixings by construction and that the new particles predicted by the models are typically assumed to be heavy, it is not clear if the models are experimentally falsifiable. In this talk, we try to shed light on the question of falsifiability by analysing the infrared features of FN models whilst staying maximally agnostic about the fine details of the model. We achieve our goal by writing down a FN effective field theory, capturing all the local interactions allowed in the ultraviolet, and matching it to the Standard Model effective field theory (SMEFT) at the tree- and 1-loop-level. Our results indicate a rich and non-trivial signature of FN models on the SMEFT Wilson coefficients, leaving us with falsifiable predictions that could be studied at current and future colliders.
- Speaker: Eetu Loisa (Cambridge U.)
- Friday 03 May 2024, 16:00-17:00
- Venue: MR19 (Potter Room, Pavilion B), CMS.
- Series: HEP phenomenology joint Cavendish-DAMTP seminar; organiser: Nico Gubernari.