This series of colloquia in the Cavendish Laboratory aims to cover all aspects of modern quantum many-body physics. It is broadly aligned with our research themes on Theoretical Condensed Matter Physics, Fundamental Physics of Quantum Matter, Applied Quantum Physics and Devices, Synthetic Quantum Systems, Quantum Information and Control, and Energy Materials
As such, it features talks on both fundamental many-body physics as well as their exploitation in devices, covering all aspects of quantum phenomena in condensed matter and synthetic many-body systems, and their theoretical description.
The aim for these colloquia is to be accessible to a wider audience compared to a typical group seminar, and everyone is most welcome to attend them!
Click below to see details of the upcoming and previous talks. Please check this page regularly to keep informed as speakers are confirmed and details of their talks are added to the list.
Upcoming talks:
Prof Claudia Felser (Max Planck Institute for Chemical Physics of Solids): Chirality and Topology
Venue: Small Lecture Theatre
Chirality is a very active field of research in organic chemistry, closely linked to the concept of symmetry. Topology, a well-established concept in mathematics, has nowadays become essential to describe condensed matter [1,2]. At its core are chiral electron states on the bulk, surfaces and edges of the condensed matter systems, in which spin and momentum of the electrons are locked parallel or anti-parallel to each other. Magnetic and non-magnetic Weyl semimetals, for example, exhibit chiral bulk states that have enabled the realization of predictions from high energy and astrophysics involving the chiral quantum number, such as the chiral anomaly, the mixed axial-gravitational anomaly and axions [3-5]. Chiral topological crystals exhibit excellent chiral surface states [6,7] and different orbital angular momentum for the enantiomers, which can be advantageous in catalysis. The potential for connecting chirality as a quantum number to other chiral phenomena across different areas of science, including the asymmetry of matter and antimatter and the homochirality of life, brings topological materials to the fore [8].
References:
[1] M. G. Vergniory, B. J. Wieder, L. Elcoro, S. S. P. Parkin, C. Felser, B. A. Bernevig, N. Regnault, Science 2022, 376, 6595.
[2] P. Narang, C. A. C. Gracia and C. Felser, Nat. Mater. 2021, 20, 293.
[3] J. Gooth et al., Nature 2017, 547, 324.
[4] J. Gooth et al., Nature 2019, 575, 315.
[5] D. M. Nenno, et al., Nat Rev Phys 2022, 2, 682.
[6] B. Bradlyn, J. Cano, Z. Wang, M. G. Vergniory, C. Felser, R. J. Cava and B. A. Bernevig, Science 2016, 353, aaf5037.
[7] N. B. M Schröter, et al., Science 2020, 369, 179.
[8] C. Felser, J. Gooth, preprint arXiv:2205.05809
Prof Jean Dalibard (Collège de France, Kaster Brossel Laboratory): Scale invariance, a hidden symmetry explored with quantum gases
Venue: Small Lecture Theatre
Scale invariance, a concept initially introduced in high-energy physics, has gained numerous applications in the physics of quantum fluids. It can be used to describe strongly interacting Fermi gases, two-dimensional Bose gases, as well as few-body systems that exhibit the "Efimov effect." This presentation will demonstrate how scale and conformal invariance emerge in cold atomic gases. Examples will be provided from a range of fields, including thermodynamics, soliton physics, and specific structures with periodic time evolution, known as "breathers".
Prof Monika Schleier-Smith (Stanford University): Atoms Interlinked by Light: Programmable Interactions and Entanglement
Venue: Small Lecture Theatre
The power of quantum information lies in its capacity to be non-local, encoded in correlations among entangled particles. Yet the interactions between particles are typically local, forming a bottleneck in the production of entanglement. To circumvent this limitation in the laboratory, we trap an array of atom clouds in an optical resonator, in which photons act as messengers conveying information between distant atoms. We have developed a versatile experimental toolbox for programming the network of interactions and correlations arising from these photon-mediated interactions, including a broadly applicable protocol for preparing entangled graph states with arbitrary connectivity. I will present experiments illustrating implications for multiparameter quantum sensing and for quantum simulations of phenomena ranging from topological physics to quantum gravity.
Prof. Peter Abbamonte (University of Illinois at Urbana-Champaign): Observation of Pines' Demon in Sr2RuO4 with Momentum-Resolved EELS
Venue: Small Lecture Theatre
The characteristic excitation of a metal is its plasmon, which is a quantized sound wave in its valence electron density. In 1965, David Pines predicted that a distinct type of plasmon, which he named a “demon,” could exist in multiband metals that contain more than one species of charge carrier. Consisting of electrons in two different bands beating out-of-phase, demons are acoustic excitations, meaning they are “massless,” meaning their energy tends toward zero as the momentum q → 0. Demons may therefore play a central role in the low-energy physics of multiband metals. However, demons are neutral excitations that do not couple to light, so they have never been observed experimentally, at least in an equilibrium, 3D material.
In this talk I will present the observation of a demon in the multiband metal Sr2RuO4. Formed of electrons in the β and γ bands, the demon is gapless with critical momentum qc = 0.08 reciprocal lattice units and room temperature velocity v = 1.065(120)×105 m/s. This study confirms a 67-year old prediction and suggests that demons may be a widespread feature of multiband metals.
*A. A. Husain, et al., Nature 621, 66 (2023)
- 14 June 2023 @16:00: Prof Joel Moore (UC Berkeley)
- 31 May 2023 @16:00: Prof Steve Kivelson (Stanford University)
- 17 May 2023 @16:00: Prof Seamus Davis (University of Oxford, University College Cork, Cornell University)
- 11 October 2023; 16:00: Prof Shivaji Sondhi (University of Oxford)
- 26 October 2023; 16:00: Prof Immanuel Bloch (Max-Planck Institute of Quantum Optics, LMU)
- 8 November 2023; 16:00: Prof Mehran Kardar (MIT)
- 15 November 2023; 16:00: Prof Eugene Demler (ETH Zürich)
- 17 January 2024; 16:00: Prof Ian Walmsley FRS (Imperial College London)
- 31 January 2024; 16:00: Prof Werner Krauth (Ecole Normale Supérieure de Paris, University of Oxford)
- 13 Feb 2024; 16:00: Prof Paolo Radaelli (University of Oxford)
- 28 February 2024; 16:00: Prof Bilge Yildiz (MIT)
- 13 March 2024; 16:00: Prof Maciej Lewenstein (ICFO – The Institute of Photonic Sciences)