Directions

We are located on the Main Campus of City in Northampton Square (map)

Getting to the Strand Campus:

• By underground

Thea nearest tube stops are Farringdon, Angel, also nearby is Barbican

• By train

Farringdon (10 minutes walk) or King's Cross stations (20 minutes walk) have nearest main-line services

• By bus

Buses stopping outside the College: : 4, 19, 30, 38, 43, 55, 56, 63, 73, 153, 205, 214, 243, 274, 341, 394, 476.

For more information http://www.city.ac.uk/new-students/travel-information.

Seminars at City, University of London

Found at least 20 result(s)

17.03.2021 (Wednesday)

D-instanton amplitude in string theory

Polygon Seminar Ashoke Sen (HCRI)

 at: 15:00 City U.room Zoom abstract: D-instantons give non-perturbative contribution to string theory amplitudes which can be computed using world-sheet techniques. However the integrals that appear in this computation often have divergences from corners of the moduli spaces which cannot be tamed by the usual procedure of analytic continuation. We show how using insights from string field theory we can extract finite unambiguous results from these apparently divergent integrals. The Zoom link will be sent by your local Triangle seminar organiser or you can contact bogdan.stefanski.1@city.ac.uk

07.12.2020 (Monday)

Lonti 2020 : D Branes and Boundary States

Regular Seminar Bogdan Stefanski (City)

 at: 11:30 City U.room Online abstract: This is the live session included as part of the LonTI lecture on Conformal blocks in two dimensions. Please register at https://lonti.weebly.com/registration.html to receive joining instructions for this live session which will be held via Zoom. D-branes are a remarkable set of soliton-like objects in string theory which have played a critical role in many areas of string theory. Despite being non-perturbative, they can be understood exactly using world-sheet methods through the boundary state formalism. In this lecture, I introduce the notion of a boundary state and show how to use it to extract physical information about D-branes and the open strings that live on them.

02.12.2020 (Wednesday)

A novel twistor string theory

Triangular Seminar Kevin Costello (Perimeter Institute)

 at: 15:00 City U.room Zoom abstract: This seminar will be held over Zoom. The link will be sent by your local Triangle seminar organiser or you can contact bogdan.stefanski.1@city.ac.uk for link. I will report on some work in progress on type I topological strings on twistor space, and their relationship with integrable but non-supersymmetric field theories in three and four dimensions. This is closely related to recent work of Bittleston and Skinner.

02.12.2020 (Wednesday)

Numerical CY metrics from holomorphic networks

Triangular Seminar Michael Douglas (Simons Center for Geometry and Physics)

 at: 16:30 City U.room Zoom abstract: This seminar will be held over Zoom. The link will be sent by your local Triangle seminar organiser or you can contact bogdan.stefanski.1@city.ac.uk for link. We propose machine learning inspired methods for computing numerical Calabi-Yau metrics, and implement them using Tensorflow/Keras. We compare them with previous work, and find that they are far more accurate for manifolds with little or no symmetry. We also discuss issues such as optimization methods, overparameterization and computational complexity. Joint work with Subramanian Lakshminarasimhan and Yidi Qi.

30.11.2020 (Monday)

LonTI 2020: D-branes and boundary states

Regular Seminar Bogdan Stefanski (City)

 at: 14:00 City U.room Youtube abstract: D-branes are a remarkable set of soliton-like objects in string theory which have played a critical role in many areas of string theory. Despite being non-perturbative, they can be understood exactly using world-sheet methods through the boundary state formalism. In this lecture, I introduce the notion of a boundary state and show how to use it to extract physical information about D-branes and the open strings that live on them.

31.03.2020 (Tuesday)

TBA

Regular Seminar Bernd Schroers (Heriot Watt)

 at: 15:00 City U.room C320 abstract:

24.03.2020 (Tuesday)

Postponed

Regular Seminar Romuald Janik (Jagielonian)

 at: 15:00 City U.room C316 abstract:

17.03.2020 (Tuesday)

Postponed

Regular Seminar Marika Taylor (Southampton)

 at: 15:00 City U.room C320 abstract:

10.03.2020 (Tuesday)

Postponed till next term

Regular Seminar Roberto Tateo (Torino)

 at: 15:00 City U.room A227 abstract:

03.03.2020 (Tuesday)

W-algebras and Yangians

Regular Seminar Tomas Prochazka (LMU Munich)

 at: 15:00 City U.room C320 abstract: I will discuss the connection between W-algebras, the higher spin generalizations of the Virasoro algebra which are the symmetry algebras in the 2-dimensional conformal field theory, and Tsymbaliuk's affine Yangian. The bridge between these two algebraic structures is the Miura operator which on one hand provides free field representations of W-algebras and on the other hand satisfies the RTT equations with Maulik-Okounkov R-matrix. The associated integrable structure allows one to easily reproduce many well-known results in conformal field theory.

18.02.2020 (Tuesday)

TBA

Regular Seminar Jose Edelstein (Santiago de Compostela)

 at: 15:00 City U.room C309 abstract:

05.02.2020 (Wednesday)

D-instantons and the non-perturbative completion of c=1 string theory

Triangular Seminar Xi Yin (Harvard)

 at: 15:00 City U.room B104 abstract: I will discuss a systematic way of taking into account non-perturbative effects on the closed string scattering amplitudes in c=1 string theory, and present a recent proposal on the corresponding non-perturbative completion of the dual matrix quantum mechanics.

05.02.2020 (Wednesday)

Revisiting long strings in c=1 string theory

Triangular Seminar Xi Yin (Harvard)

 at: 16:30 City U.room B104 abstract: I will discuss FZZT branes and long strings in c=1 string theory, and the dual description of the latter in non-singlet sectors of the matrix quantum mechanics. I will present highly nontrivial evidences for the duality at the level of perturbative scattering amplitudes, and discuss implications on black holes in c=1 string theory and their matrix model duals.

04.02.2020 (Tuesday)

Stochastic modeling of diffusion in dynamical systems: three examples

Regular Seminar Rainer Klages (QMUL)

 at: 15:00 City U.room C309 abstract: Consider equations of motion yielding dispersion of an ensemble of particles. For a given dynamical system an interesting problem is not only what type of diffusion is generated but also whether the resulting diffusive dynamics matches to a known stochastic process. I will discuss three examples of dynamical systems displaying different types of diffusive transport: The first model is fully deterministic but nonchaotic by showing a whole range of normal and anomalous diffusion under variation of a single control parameter [1]. The second model is a soft Lorentz gas where a point particles moves through repulsive Fermi potentials situated on a triangular periodic lattice [2]. It is fully deterministic by displaying an intricate switching between normal and superdiffusion under variation of control parameters. The third model randomly mixes in time chaotic dynamics generating normal diffusive spreading with non-chaotic motion where all particles localize [3]. Varying a control parameter the mixed system exhibits a transition characterised by subdiffusion. In all three cases I will show successes, failures and pitfalls if one tries to reproduce the resulting diffusive dynamics by using simple stochastic models. Joint work with all authors on the references cited below. [1] L. Salari, L. Rondoni, C. Giberti, R. Klages, Chaos 25, 073113 (2015) [2] R.Klages, S.S.Gallegos, J.SolanpÂ¨aÂ¨a, M.Sarvilahti, Phys. Rev. Lett. 122, 064102 (2019) [3] Y.Sato, R.Klages, Phys. Rev. Lett. 122, 174101 (2019)

28.01.2020 (Tuesday)

TBA

Regular Seminar Jacopo de Nardis (Ghent)

 at: 15:00 City U.room C316 abstract:

21.01.2020 (Tuesday)

TBA

Regular Seminar Elli Pomoni (DESY)

 at: 15:00 City U.room c309 abstract:

11.12.2019 (Wednesday)

Applied Geometric Mechanics: Symmetries in Physics

Conference A workshop (City, University of London)

 at: 10:30 City U.room ELG03 abstract: This workshop gives a flavour of where and how different types of symmetries are employed in the modern context of quantum theories. The workshop will cover the interplay between discrete (CPT) and continuous Lie group symmetries. For instance, conformal symmetries in the form of infinite-dimensional Virasoro in quantum field theories, Kac-Moody algebras in the study of string sigma-models, Lorentzian Kac-Moody algebras (e.. E11) in the description of string and brane theories, and quantum group symmetries in the study of integrable systems. Speakers: Andrea Cavaglia (King's College London) Anastasia Doikou (Heriot-Watt University, Edinburgh) Valentina Forini (City, University of London) Vidas Regelskis (University of Hertfordshire and Vilnius University) Takanobu Taira (City, University of London) Peter West (King's College London) https://cityagm.weebly.com/

06.12.2019 (Friday)

Fermionic entanglement on the torus

Regular Seminar Ignacio Reyes (AEI)

 at: 12:00 City U.room A107 abstract: Concepts from quantum information theory have become increasingly important in our understanding of entanglement in QFTs. One prominent example of this is the modular Hamiltonian, which is closely related to the Unruh effect. Using complex analysis, we determine this operator for the chiral fermion at finite temperature on the circle and show that it exhibits surprising new features. This simple system illustrates how a modular flow can transition from complete locality to complete non-locality, thus bridging the gap between previously known limits. We derive the first exact results for the entropy in the different spin sectors, and comment on the analytic continuation of the RÃ©nyi entropies to the complex plane.

03.12.2019 (Tuesday)

Postponed due to strike till Friday

Regular Seminar Ignacio Reyes (AEI)

 at: 15:00 City U.room B103 abstract:

26.11.2019 (Tuesday)

TBA

Regular Seminar Laure Daviaud (City)

 at: 15:00 City U.room B103 abstract: Postponed due to strike