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Department of Physics

The Cavendish Laboratory

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 PhysicsFundamental Physics of Quantum MatterApplied Quantum Physics and DevicesSynthetic Quantum SystemsQuantum 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:

11 October 2023 @16:00: Prof Shivaji Sondhi (University of Oxford)

Prof Shivaji Sondhi (University of Oxford)

Venue: Small Lecture Theatre

Title and abstract: 

Quantum Mechanics and Many Body Games
I will describe some work on the theme of exploring many body quantum mechanics by playing games with its help. One set of results raises the possibility of classifying quantum states by asking whether they confer a quantum advantage in winning a particular game. The second set explores the space of entangled states by setting up a game in which two players compete to entangle and disentangle a shared set of qubits.

26 October 2023 @16:00: Prof Immanuel Bloch (Max-Planck Institute of Quantum Optics, LMU)

Prof Immanuel Bloch (Max-Planck Institute of Quantum Optics, LMU)

Venue: Small Lecture Theatre

Title and abstract: 

New Avenues for Quantum Simulations In- and Out-of-equilibrium

Quantum simulation using ultracold atoms and molecules has opened a new research field to probe quantum matter in- and out-of-equilibrium using novel observational an engineering techniques at the single atom level. In fermionic quantum matter, the systems are now cold enough to enter the pseudogap regime and reveal intriguing higher order quantum correlations in doped Hubbard systems. We also explore a new high-temperature pairing mechanism in mixed two-dimensional systems that dramatically boosts the pairing energy of holes. In quantum dynamics, probing the full counting statistics of charge transfer allows to explore quantum transport in fundamentally new ways. We test this for the cases of integrable and chaotic quantum dynamics, where for the latter case local subsystems eventually approach a thermal equilibrium state. Large subsystems, however, thermalize slower: their approach to equilibrium is limited by the hydrodynamic build-up of large-scale fluctuations. We show that large-scale fluctuations of isolated quantum systems display emergent hydrodynamic behaviour, expanding the applicability of macroscopic fluctuation theory to the quantum regime.

8 November 2023 @16:00: Prof Mehran Kardar (MIT)

Prof Mehran Kardar (MIT)

Venue: Small Lecture Theatre

Title and abstract: 

Forces from fluctuations in and out of equilibrium (in QED and Active Matter)

The pressure of a gas, the van der Waals attraction between molecules, and the Casimir force in quantum electrodynamic (QED) are common examples of forces resulting from equilibrium (thermal or quantum) fluctuations. Current research on “Active Matter” studies collective behaviors of large groups of self-driven entities (living or artificial), whose random motions superficially resemble thermally fluctuating particles. However, the absence of time reversal symmetry leads to unusual phenomena such as directed (ratchet) forces, and a pressure that depends on the shape and structure of the confining wall.

Some manifestations of QED fluctuations out of thermal equilibrium are well-known, as in the Stefan-Boltzmann laws of radiation pressure and heat transfer. These laws, however, acquire non-trivial twists in the near-field regime of sub-micron separations, and in the proximity of moving surfaces.  Symmetry arguments suggest that lateral ratchet forces should emerge out of equilibrium and with broken spatial symmetry. We inquire if such forces can be used to construct a heat engine, and discuss constraints on its operation.


15 November 2023 @16:00: Prof Eugene Demler (ETH Zürich)

Prof Eugene Demler (ETH Zürich)

Venue: Small Lecture Theatre

Title and abstract: 

Lighting up superconductivity

Recent experiments suggest the phenomenon of light induced superconductivity above Tc in two different materials: fullerene superconductor K3C60 and high Tc cuprate YBCO. I will discuss the distinct phenomena taking place in these systems. In K3C60, the unusual character of electron-phonon interactions results in enhanced BCS pairing through optical driving and the slow relaxation of superconducting correlations after they have been created. In YBCO the light induced state is short lived and its properties can be explained from the perspective of a Floquet material. I will present a general theoretical framework for understanding Floquet materials, in which the pump-induced oscillations of a collective mode lead to the parametric generation of excitation pairs. This can result in features such as photo-induced edges in reflectivity, enhancement of reflectivity, and even light amplification.


17 January 2024 @16:00: Prof Ian Walmsley FRS (Imperial College London)

Prof Ian Walmsley FRS (Imperial College London)

Venue: Small Lecture Theatre

Title and abstract coming soon.