Fri 10 Oct 16:00: Application of Open Quantum System Concepts to Internal Wave / Planetary Wave Coupling and consequences for Earth System Behaviour
We assess a prognostic formulation of triple coherence relating to energy exchange between mesoscale eddies and the internal wavefield and compare with observations from the Sargasso Sea.
We break new ground in the following ways: (1) We utilize concepts from Open Quantum Systems to arrive at the essential results presented in Muller 1976, JFM , where eddy induced internal wave-stress perturbations are damped using a nonlinear relaxation time scale approximation. The broad brush take on Open Quantum Systems is that there is a system (ray tracing), a bath (the background internal wavefield) and a system bath interaction (nonlinear relaxation). We avoid the asymptotic expansion involving small perturbations to wave phase speed that is the basis of Muller.
(2) We define the background internal wave spectrum based upon a regional characterization of the wavefield in the Sargasso Sea. This differs from the canonical description referred to as GM76 in crucial respects.
(3) We use recent theoretical work on both extreme scale separated interactions and the internal wave kinetic equation to properly define nonlinear relaxation time scales.
Agreement of the prognostic formulation with data is remarkable and is consistent with eddy-wave coupling dominating the regional internal wave energy budget, as in the diagnostic study of Polzin 2010, JPO , using data from the Local Dynamics Experiment of PolyMode III , circa 1978-1979. Extraction of eddy energy happens at the horizontal and vertical scales that characterize baroclinic instability and potential vorticity fluxes. The goodness of this effort reinforces a prior hypothesis (Polzin and Lvov 2011, RoG) that the character of the internal wavefield in the Sargasso Sea is set by this interaction, which, in turn, serves as an amplifier of tertiary energy inputs from larger vertical scales that characterize internal swell. With this knowledge and confidence, we then speculate on the role that this coupling plays in mesoscale eddy dynamics in the Southern Recirculation Gyre of the Gulf Stream. In this instance our interest is the potential enstrophy budget, in which enstrophy is the square of the perturbation potential vorticity and, as is energy, an inviscid invariant.
We argue that this nonlinear relaxation effectively provides a local eddy enstrophy damping consistent with potential vorticity flux observations from the Local Dynamics Experiment. This happens at spatial scales somewhat smaller than the energy extraction scale and locates the end of the potential enstrophy cascade in the spectral domain as the energy containing scale of the internal wavefield. We offer insight into how such speculation might acquire firmer ground by describing how to incorporate modulations of the lower bound of internal wave frequency by potential vorticity perturbations into the existing formulation. In the context of a formal WKB approximation, the current formulation stands as a ‘geometric optics’ approximation controlling system behavior whereas modulations of the waveguide are a ‘physical optics’ correction.
Regardless, the dynamical consequence is that wave-eddy coupling is responsible for the maintenance of gyre scale potential vorticity gradients that are crucial to Rossby wave propagation and Earth system behavior.
- Speaker: Kurt Polzin, Woods Hole Oceanographic Institution
- Friday 10 October 2025, 16:00-17:00
- Venue: MR2.
- Series: Fluid Mechanics (DAMTP); organiser: Duncan Hewitt.
Thu 23 Oct 14:30: Lonely runners and their spectra
Dirichlet’s Theorem from Diophantine approximation says that for any real number t, there is some v in {1,2,...,n} such that tv lies within 1/(n+1) of an integer. The Lonely Runner Conjecture of Wills and Cusick asserts that the constant 1/(n+1) in this theorem cannot be improved by replacing {1,2,...,n} with a different set of n nonzero real numbers. The conjecture, although now more than 50 years old, remains wide open for n larger than 7. In this talk I will describe a new approach based on the “Lonely Runner spectra” that arise when one considers the “inverse problem” for the Lonely Runner Conjecture. Based on joint work with Vikram Giri and with Vanshika Jain.
- Speaker: Noah Kravitz (Oxford)
- Thursday 23 October 2025, 14:30-15:30
- Venue: MR12.
- Series: Combinatorics Seminar; organiser: ibl10.
Thu 23 Oct 14:30: Lonely runners and their spectra
Dirichlet’s Theorem from Diophantine approximation says that for any real number t, there is some v in {1,2,...,n} such that tv lies within 1/(n+1) of an integer. The Lonely Runner Conjecture of Wills and Cusick asserts that the constant 1/(n+1) in this theorem cannot be improved by replacing {1,2,...,n} with a different set of n nonzero real numbers. The conjecture, although now more than 50 years old, remains wide open for n larger than 7. In this talk I will describe a new approach based on the “Lonely Runner spectra” that arise when one considers the “inverse problem” for the Lonely Runner Conjecture. Based on joint work with Vikram Giri and with Vanshika Jain.
- Speaker: Noah Kravitz (Oxford)
- Thursday 23 October 2025, 14:30-15:30
- Venue: MR12.
- Series: Combinatorics Seminar; organiser: ibl10.
Mon 03 Nov 11:00: LMB Seminar - How the physical sciences can empower biology : Applications of single molecule fluorescence to the biosciences
The capability to image single molecules has revolutionised biology. I will explain how these methods work and how we are currently applying them to study the molecular basis of neurodegenerative disease. Lastly I will describe how our early single molecule work on DNA polymerase led to the development of next generation DNA sequencing, now widely used, and the lessons that can be learnt from this experience.
- Speaker: David Klenerman, University of Cambridge
- Monday 03 November 2025, 11:00-12:00
- Venue: In person in the Max Perutz Lecture Theatre (CB2 0QH) and via Zoom link https://mrc-lmb-cam-ac-uk.zoom.us/j/94171771196?pwd=LbKuOThopk72DktYw3WJWcjBOGlKgG.1.
- Series: MRC LMB Seminar Series; organiser: Scientific Meetings Co-ordinator.
Thu 13 Nov 16:30: Prof Mark Cragg, Professor in Experimental Cancer Biology, University of Southampton Note unusual time
Host: Tim Halim, CRUK
Note unusual time
- Speaker: Prof Mark Cragg, Professor in Experimental Cancer Biology, University of Southampton
- Thursday 13 November 2025, 16:30-17:30
- Venue: Lecture Theatre, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus.
- Series: Cambridge Immunology Network Seminar Series; organiser: Liat Churley.
Wed 29 Oct 13:30: Polynomial bounds for Chowla's cosine problem
Inspired by investigations of zeta functions, and old problem of Ankeny and Chowla asks whether any cosine polynomial f_A(x)=cos(a_1 x)+ ... +cos(a_n x), for an arbitrary set A={a_1,...a_n} of n distinct positive integers, must take a large negative value for some x in [0,2 pi]. Chowla later conjectured that the largest negative value of f_A is always at least of order n1/2, for any set A of size n. A refinement of Bourgain’s approach due to Ruzsa gave the previous record bound of exp(sqrt(log n)). In this talk, we discuss recent progress establishing the first polynomial bound nc with exponent c=1/7. We remark that Jin, Milojevic, Tomon and Zhang independently proved a polynomial bound with exponent c approximately 1/100 using a different method.
- Speaker: Benjamin Bedert (University of Cambridge)
- Wednesday 29 October 2025, 13:30-14:30
- Venue: MR4, CMS.
- Series: Discrete Analysis Seminar; organiser: Julia Wolf.
Wed 05 Nov 14:00: Title to be confirmed
Abstract not available
- Speaker: Dr Fulvio Paleari (CNR Istituto Nanoscienze, Modena)
- Wednesday 05 November 2025, 14:00-15:30
- Venue: Seminar Room 3, RDC.
- Series: Theory of Condensed Matter; organiser: Bo Peng.
Tue 21 Oct 14:00: Scalable and Verifiable Carbon Accounting in Supply Chains: Towards an Integrated Framework
Companies need reliable emission data for their products and services to take effective climate action, yet obtaining it is challenging. In today’s interconnected economy, product and service carbon footprints (PCF) cannot be determined in isolation but require emission data exchange throughout supply chains. Typical cradle-to-gate accounting models require companies to include suppliers’ PCFs as scope 3 emissions, making the trustworthiness of this externally provided data critical. This calls for effective emission data verification to prevent greenwashing and ensure consistency, but current methods face fundamental limitations: they are either non-scalable (e.g., relying on individual auditors) or require access to suppliers’ confidential business information. Trust-enhancing technologies like zero-knowledge proofs (zk-SNARKs), combined with verifiable decentralized data structures, can resolve this tension by enabling verification without exposing confidential trading information. This talk introduces verifiable carbon accounting (VCA) as a framework that synthesizes multiple such technologies to enable scalable, confidentiality-preserving emission data verification. We provide an overview of recent and ongoing research, present open challenges, and discuss practical adoption strategies. While still in its infancy, VCA has the potential to transform data-driven supply chain collaboration by offering a scalable alternative to existing approaches while delivering the trustworthy emission data urgently needed to combat climate change.
Bio: Jonathan Heiss is a postdoctoral researcher at TU Berlin, Germany, and a senior research engineer at SINE Foundation. He earned his Ph.D. in computer science from TU Berlin in 2023 and holds two master’s degrees from TU Delft (computer science) and TU Berlin (ICT Innovation), both completed in 2017. He received his bachelor’s degree in information systems from TU Dresden in 2015. Jonathan’s research focuses on trustworthy distributed systems engineering, with particular emphasis on incorporating trust-enhancing technologies such as zero-knowledge proofs, secure hardware, and verifiable data structures into platform-based system architectures. Target platforms include cloud systems and blockchain networks, and their synergistic combination and interplay. He employs research methods drawn from software engineering and distributed systems, including systems modeling, prototyping, and experiment- and measurement-driven approaches. Recent work applies these technologies to contexts such as decentralized federated learning and carbon accounting.
- Speaker: Jonathan Heiss (TU Berlin)
- Tuesday 21 October 2025, 14:00-15:00
- Venue: Webinar & FW11, Computer Laboratory, William Gates Building..
- Series: Computer Laboratory Security Seminar; organiser: Alexandre Pauwels.
Fri 10 Oct 08:45: MicroRNA expression in histiocytic sarcomas of flat-coated retrievers
Meytar graduated from University of Cambridge in 2022. She spent a year in clinical GP practice in London before returning to Cambridge for her Oncology internship and she is now in her first year of her Oncology residency.
- Speaker: Meytar Ronel, Department of Veterinary Medicine
- Friday 10 October 2025, 08:45-10:00
- Venue: LT2.
- Series: Friday Morning Seminars, Dept of Veterinary Medicine; organiser: Fiona Roby.
Fri 10 Oct 08:45: Nasal Mucosal Leishmaniasis: Clinical Features, Gaps in Models, and a New Experimental Direction?
Julieth is a researcher studying macrophage biology in both sterile and infectious contexts. She completed her PhD in Colombia, focusing on Macrophage-Leishmania interactions using omics approaches, which sparked her interest in developing resources for omics analysis in infectious diseases. At the EBI , she contributed to creating the first repository of pathways relevant to Leishmaniasis. Currently, she is working with Professor Bryant on macrophage involvement in inflammation under sterile conditions and in response to canonical activators of Toll-like receptors. She employs transcriptomics, ATAC -seq data, and graph theory to study these systems in native and perturbed conditions.
- Speaker: Julieth Murillo Silva, Department of Veterinary Medicine
- Friday 10 October 2025, 08:45-10:00
- Venue: LT2.
- Series: Friday Morning Seminars, Dept of Veterinary Medicine; organiser: Fiona Roby.
Mon 20 Oct 14:00: Talk by Professor Bjarne Stroustrup: 'Concept-based Generic Programming'
For more details about the talk, and if you would like to attend, please visit: https://www.eventbrite.co.uk/e/talk-by-professor-bjarne-stroustrup-concept-based-generic-programming-tickets-1742215837469?aff=oddtdtcreator
- Speaker: Bjarne Stroustrup, Professor of Computer Science at Columbia University
- Monday 20 October 2025, 14:00-15:30
- Venue: LT1, Computer Laboratory, William Gates Builiding.
- Series: Department of Computer Science and Technology talks and seminars; organiser: Kata Szabo.
Wed 29 Oct 15:05: Standing on the Shoulders of Giants
Western Cultural Evolution of Computational Reasoning from Pythagoras to the Cloud & AI Era.
This talk falls into the category of “Big History” that provides a mostly Western multi-disciplinary perspective of our modern technological world and the gradual evolution over-time of computational reasoning starting roughly 500 BC in Athens and continuing to today and our new world of AI.
Link to join virtually: https://cam-ac-uk.zoom.us/j/89473073451
This talk is being recorded. If you do not wish to be seen in the recording, please avoid sitting in the front three rows of seats in the lecture theatre. Any questions asked will also be included in the recording. The recording will be made available on the Department’s webpage
- Speaker: Dr Greg Lavender - Former CTO of Intel and VMware Trustee, American School of Classical Studies at Athens
- Wednesday 29 October 2025, 15:05-15:55
- Venue: Lecture Theatre 1, Computer Laboratory, William Gates Building.
- Series: Wednesday Seminars - Department of Computer Science and Technology ; organiser: Ben Karniely.
Tue 14 Oct 14:00: On large clusters for the Gaussian free field
The talk will focus on the percolation problem associated to excursion sets of the Gaussian free field. The cable-system version of this percolation model enjoys a certain integrability, which permits unprecedented conclusions at and near the critical point, especially in low transient dimensions. We will give a gentle introduction to this circle of ideas, with the aim to discuss the tail behaviour of the cluster size of a point, as well as the largest cluster size. Based on work with A. Drewitz and A. Prévost.
- Speaker: Pierre-François Rodriguez (Statslab)
- Tuesday 14 October 2025, 14:00-15:00
- Venue: MR12.
- Series: Probability; organiser: Perla Sousi.
Wed 15 Oct 15:00: Ageing without microbes – An old dialogue between microbes and mitochondria
Prolongation of lifespan is one of the greatest achievements of modern medicine. As an unfortunate consequence, age-related diseases are thriving. A comprehensive understanding of the ageing process is therefore crucial for healthy ageing. While human host genetics are not straightforward to tinker with, diet and the microbiota are excellent untapped opportunities to improve disease states. Dysbiosis has been recently proposed as a hallmark of ageing through the development of a chronic low-grade inflammatory state, and may be one of the driving factors behind age-related diseases. Using model systems including germ-free and conventionally raised wildtype and mitochondrial deficient progeria mouse models, we investigate the role of gut microbiota in the development of age-related phenotypes to identify tissue cross-talk regulators modulated by the microbiota. The promising research endeavors in this area are the identification of early biomarkers and actionable mechanisms for improving healthy ageing.
- Speaker: Professor Filipe Cabreiro, University of Cologne, Germany
- Wednesday 15 October 2025, 15:00-16:00
- Venue: MRC MBU, Level 7 Lecture Theatre, The Keith Peters Building, CB2 0XY.
- Series: MRC Mitochondrial Biology Unit Seminars; organiser: Lisa Arnold.
Tue 21 Oct 11:00: Emerging importance of chemistry-climate coupling on weather to climate timescales https://teams.microsoft.com/l/meetup-join/19%3ameeting_Y2VhNTk0OWMtNDc4Mi00YzVjLTkzYTUtNGM3MjU4OTYzMTJl%40thread.v2/0?context=%7b%22Tid%22%3a...
Abstract:
Two-way feedbacks between atmospheric composition changes and climate dynamics have gained increasing attention due to its critical role in weather and climate prediction. In this talk, I will provide a broad overview of the field’s development and highlight where chemistry-climate interactions are considered most significant. I will present a range of examples based on advanced modeling and newly developed observational climate data records to illustrate chemistry–climate coupling across timescales from S2S weather patterns to long-term climate trends. These include the influence of dynamical processes and abrupt events—such as sudden stratospheric warmings and the Hunga Tonga eruption—on stratospheric composition anomalies and their feedbacks on meteorological and climate phenomena. I will also discuss the impacts of stratospheric ozone depletion and recovery on climate radiative forcing and atmosphere–ocean dynamics. Finally, I will present a storyline approach to future air pollution and how air pollution impacted methane (and thus climate) over the recent past. Collectively, these findings emphasize the critical feedback loops between atmospheric composition and climate dynamics via radiative processes and underscore the need for realistic representation of composition anomalies in weather forecasting systems and climate models.
Short bio:
Prof. Dr Michaela I. Hegglin holds an MSc in Environmental Science (2000) and a PhD in Atmospheric Science (2004) from ETH Zurich in Switzerland. After seven years at the University of Toronto as Postdoc and Research Associate she moved in 2012 to the Meteorology Department at the University of Reading where she progressed through the ranks and was promoted to Full Professor in 2022. Since March 2022 she took on the position as Director of the Institute of Climate and Energy Systems – Stratosphere (ICE-4) at the Research Centre Julich, Germany, and holds a Full Professorship at the University of Wuppertal.
Michaela’s main expertise lies in Earth observations, atmospheric chemistry and transport, upper troposphere and lower stratosphere processes, stratospheric ozone, air pollution, chemistry-climate coupling, and Earth-system model evaluation. She has occupied numerous leadership roles within Future Earth, the World Climate Research Programme, and the World Meteorological Organisation/United Nations Environment Programme (WMO/UNEP) Scientific Assessments of Ozone Depletion, and is currently Principal Investigator of the European Space Agency’s Water Vapour Climate Change Initiative.
https://teams.microsoft.com/l/meetup-join/19%3ameeting_Y2VhNTk0OWMtNDc4Mi00YzVjLTkzYTUtNGM3MjU4OTYzMTJl%40thread.v2/0?context=%7b%22Tid%22%3a%2249a50445-bdfa-4b79-ade3-547b4f3986e9%22%2c%22Oid%22%3a%228b208bd5-8570-491b-abae-83a85a1ca025%22%7d
- Speaker: Prof Michaela I. Hegglin, Director at the Institute of Climate and Energy Systems of the Forschungszentrum Jülich (Germany)
- Tuesday 21 October 2025, 11:00-12:00
- Venue: Chemistry Dept, Unilever Lecture Theatre and Teams.
- Series: Centre for Atmospheric Science seminars, Chemistry Dept.; organiser: Yao Ge.
Thu 09 Oct 15:00: [Postponed!] Reliable and Sustainable AI: From Mathematical Foundations to Next Generation AI Computing
[Please note this talk has been postponed, further details TBC ]
- Speaker: Gitta Kutyniok, Ludwig-Maximilians-Universität München
- Thursday 09 October 2025, 15:00-16:00
- Venue: Centre for Mathematical Sciences, MR14.
- Series: Applied and Computational Analysis; organiser: Matthew Colbrook.
Tue 04 Nov 16:00: Energy in spacetimes with negative cosmological constant
This talk will discuss global and quasilocal properties of energy in spacetimes with negative cosmological constant using spinor methods. In the first half of the talk, a general positive energy theorem is developed for asymptotically, locally AdS spacetimes with boundary geometry admitting compact cross-sections with parallel or Killing spinors. Various examples will be used to illustrate the effect of the boundary geometry. In the second half of the talk, a new notion of quasilocal mass will be defined for generic, compact, 2D, spacelike surfaces in 4D spacetimes with negative cosmological constant. The new quasilocal mass is based on work for vanishing cosmological constant by Penrose and Dougan & Mason and will be shown to have a number of physically desirable properties.
- Speaker: Virinchi Rallabhandi (University of Edinburgh)
- Tuesday 04 November 2025, 16:00-17:00
- Venue: CMS MR11.
- Series: Mathematical Physics Seminar; organiser: Professor Maciej Dunajski.
Tue 11 Nov 16:00: Black Hole Binary Dynamics and High Precision Gravitational Scattering
Gravitational wave signals from coalescing binary black holes are detected, and analyzed, by using large banks of template waveforms. The construction of these templates makes an essential use of the analytical knowledge of the motion and radiation of gravitationally interacting binary systems. A new angle of attack on gravitational dynamics consists of considering (classical or quantum) scattering states. Recent results obtained by such scattering approaches will be reviewed.
- Speaker: Thibault Damour (Institut des Hautes Etudes Scientifiques)
- Tuesday 11 November 2025, 16:00-17:00
- Venue: CMS MR11.
- Series: Mathematical Physics Seminar; organiser: Professor Maciej Dunajski.
Tue 21 Oct 16:00: Standing gravitational waves
Standing waves play an important role in many branches of physics. In general relativity, the nonlinearity of the Einstein equations makes the analysis challenging, and the nature of standing gravitational waves remains incompletely understood. In this talk, I will present recent developments on this topic.
- Speaker: Sebastian Szybka (Jagiellonian University, Krakow)
- Tuesday 21 October 2025, 16:00-17:00
- Venue: CMS MR11.
- Series: Mathematical Physics Seminar; organiser: Professor Maciej Dunajski.
Fri 10 Oct 15:00: Nonlinear multiscale structure optimization: vibration, cloaking and snap-through
We will introduce the multiscale optimization of graded lattice micro-structures which enable useful and potentially unintuitive behaviour at the macroscale. We will first consider a vibration control case in which the macro-scale dynamic modes and resonant frequencies of a structure can be precisely tailored without changing the global geometry and mass. This has particular relevance for the design of structures designed for launch applications. It will then be demonstrated how the inclusion of geometric and material nonlinearity in the optimization enables unusual emergent properties, including mechanical cloaking and the synthesis of microstructures exhibiting snap-through and bistable responses.
- Speaker: Matthew Santer, Imperial College London, UK
- Friday 10 October 2025, 15:00-16:00
- Venue: CivEng Seminar Room (1-33) (Civil Engineering Building).
- Series: Engineering Department Structures Research Seminars; organiser: Shehara Perera.