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.
Venue and Time: Wednesday 11 February 2026, 16:15, Ray Dolby Auditorium, Ray Dolby Centre, Cavendish Laboratory, JJ Thomson Avenue, CB3 0US.
Title: Emergent physics in atomically thin semiconductors
Abstract:
When two atomically thin semiconductor layers are stacked with a twist, interaction between electrons become dominant over their kinetic energy. Such a system provides a fertile ground for investigation of new physics, such as magnetism with kinetic origin or quantum Hall states in the absence of a magnetic field.
If you have a question about this talk, please contact Andrea Pizzi.
Venue and Time: Thursday 26 February 2026, 16:15, Ray Dolby Auditorium, Ray Dolby Centre, Cavendish Laboratory, JJ Thomson Avenue, CB3 0US.
Title: Novel quantum dynamics with superconducting qubits
Abstract:
The prevailing view is that quantum phenomena can be leveraged to tackle certain problems beyond the reach of classical approaches. Recent years have witnessed significant progress in this direction; in particular, superconducting qubits have emerged as one of the leading platforms for quantum simulation and computation on Noisy Intermediate-Scale Quantum (NISQ) processors. This progress is exemplified by research ranging from the foundations of quantum mechanics [1] to the non-equilibrium dynamics of elementary excitations [2] and condensed matter physics [3,4]. By utilizing the contextuality of quantum measurements to solve a 2D hidden linear function problem, we demonstrate a quantum advantage through a computational separation for up to 105 qubits on these bounded-resource tasks [1]. Motivated by high-energy physics, we image charge and string dynamics in (2+1)D lattice gauge theories [2], revealing two distinct regimes within the confining phase: a weak-confinement regime with strong transverse string fluctuations and a strong-confinement regime where these fluctuations are suppressed. Turning to condensed matter, we observe novel localization in one- and two-dimensional many-body systems that lack energy diffusion despite being disorder-free and translationally invariant [3]. Additionally, we show that strong disorder in interacting multi-level landscapes can induce superfluidity characterized by long-range phase coherence [4]. Together, these results show that NISQ processors, even without fault tolerance, are powerful tools for probing and advancing our understanding of complex non-equilibrium quantum dynamics.
If you have a question about this talk, please contact Andrea Pizzi.
Venue and Time: Wednesday 03 December 2025, 16:15, Ray Dolby Auditorium, Ray Dolby Centre
Title: Cold Atom Quantum Technology to Explore Fundamental Physics
Abstract:
In this presentation, I will outline the scientific opportunities enabled by a multi-stage programme based on cold-atom quantum technology. The central objectives of this programme include the search for ultra-light dark matter, the exploration of gravitational waves in the mid-frequency band—bridging the sensitivity gap between LISA and ground-based detectors such as LIGO , Virgo, KAGRA , INDIGO, the Einstein Telescope, and Cosmic Explorer—and the investigation of other frontiers in fundamental physics. This research will complement ongoing dark-matter searches, probe mergers involving intermediate-mass black holes, and shed light on early-universe cosmology. I will particularly focus on major initiatives in this field, including the AION project in the UK and the international Terrestrial Very-Long-Baseline Atom Interferometry (TVLBAI) proto-collaboration, which is now formally established. TVLBAI aims to develop a global network of large-scale atom interferometers designed to detect ultra-light dark matter and gravitational waves, with the long-term goal of deploying kilometre-scale detectors by the mid-2030s. The proto-collaboration is currently defining a detailed scientific and technological roadmap, identifying the key milestones required to realise these next-generation quantum detectors.
If you wish to meet the speaker, please contact ap2076@cam.ac.uk to be added to their visit schedule.
If you have a question about this talk, please contact Andrea Pizzi.
Venue and Time: Wednesday 12 November 2025, 16:15, Ray Dolby Auditorium, Ray Dolby Centre, Cavendish Laboratory, JJ Thomson Avenue, CB3 0US.
Title: Tensor networks: entanglement as building blocks of quantum matter
Abstract:
The talk will introduce tensor networks, a tool which uses entanglement theory to describe quantum many-body wavefunctions. An essential ingredient in tensor networks is the fact that the global properties of the wavefunction (such as order parameters and topological features) are encoded in the symmetries of local tensors. As such, tensor networks provide an extremely versatile tool to describe ground states of a wide variety of strongly correlated systems. Tensor networks have also been successful in debunking quantum supremacy claims. This talk will give an overview of the theory and applications of tensor networks.
If you wish to meet the speaker, please contact db985@cam.ac.uk to be added to their visit schedule.
If you have a question about this talk, please contact Diego Barberena.
Venue and Time: Wednesday 29 October 2025, 16:15, Ray Dolby Auditorium, Ray Dolby Centre, Cavendish Laboratory, JJ Thomson Avenue, CB3 0US.
Title: Theory of g factors in semiconductors — some history, and new insights
Abstract:
The g factor of electrons and holes in crystals and heterostructures of silicon, germanium, gallium arsenide, etc., is a key parameter in designing spin qubits. I will begin by discussing two different but interrelated definitions of the g factor. Authors have disagreed from the beginning about whether or not g is a symmetric second-rank tensor. I will discuss that g, which is specific to each eigenstate, whether extended or localized, is best discussed in terms of three singular values associated with eigendirections, with a separate discussion about its sign. Luttinger gave a correct formula for the g factors of band electrons, including the orbital contributions arising from the spin-orbit interaction. But it was not until fifty years later, with the advent of Berry-curvature concepts, that his formula could be given a clear physical interpretation. I will show results of a survey we have done of band g factors in silicon and germanium, emphasizing new topological aspects. It is interesting that even silicon, with its very weak spin-orbit interaction, can, because of a combination of topology and symmetry, exhibit g factors very far from 2.
If you have a question about this talk, please contact Andrea Pizzi.
If you wish to meet the speaker, please contact ap2076@cam.ac.uk to be added to their visit schedule.
Venue and Time: Wednesday 15 October 2025, 16:15, Cluster Seminar Room, Ray Dolby Centre.
Title: Hunting for Hidden Order
Abstract:
Most magnetic materials, phenomena and devices are well described in terms of the magnetic dipoles arising from the spin of their constituent electrons. There is mounting evidence, however, of intriguing magnetic behaviors that can’t be explained in terms of electron spin dipole moments; these behaviors are often attributed to “hidden order” since their origin is difficult to decipher with conventional experimental probes. In this talk I will discuss some unusual magnetic effects, such as electric-field induced magnetism, magnetism on apparently non-magnetic surfaces, and unconventional spin splitting of energy bands, and show that they can be understood in terms of a “hidden order” of higher-order magnetic multipoles, beyond the magnetic dipole. While there are clear experimental signatures of such hidden multipolar order, and it is captured nicely in our computer simulations, attempts at direct measurement have so far proved elusive, and I will close with a plea for better ideas.
If you have a question about this talk, please contact Andrea Pizzi.
Venue and Time: Wednesday 08 October 2025 at 16:15, Lecture Teatre, Ray Dolby Centre.
Title: Non-reciprocal phase transitions
Abstract:
Spontaneous synchronization is at the core of many natural phenomena. Your heartbeat is maintained because cells contract in a synchronous wave; some bird species synchronize their motion into flocks; quantum synchronization is responsible for laser action and superconductivity. The transition to synchrony, or between states of different patterns of synchrony, is a dynamical phase transition that has much in common with conventional phase transitions of state – for example solid to liquid, or magnetism – but the striking feature of driven dynamical systems is that the components are “active”. Consequently quantum systems with dissipation and decay are described by non-Hermitian Hamiltonians, and active matter can abandon Newton’s third law and have non-reciprocal interactions. This substantially changes the character of many-degree-of-freedom dynamical phase transitions between synchronized steady states and the critical phenomena in their vicinity, since the critical point is an “exceptional point” where eigenvalues become degenerate and eigenvectors coalesce. We will illustrate this in several different systems – a Bose-Einstein condensate of polaritons, models with cavity mediated interactions, and models of multicomponent active matter such as flocks of birds, generalized Kuramoto models, and Wilson-Cowan models of neural networks. We argue that there is a systematic theory and generalized phase diagram, and corresponding universality behaviors determined by the symmetry of the models.
If you have a question about this talk, please contact Andrea Pizzi.
Venue and time: 04 June 2025 at 16:15, Lecture Theatre, RDC
Title: The Magic of Moiré Quantum Matter
Abstract:
The understanding of strongly-interacting quantum matter has challenged physicists for decades. The discovery seven years ago of correlated phases and superconductivity in magic angle twisted bilayer graphene has led to the emergence of a new materials platform to investigate strongly interacting physics, namely moiré quantum matter. These systems exhibit a plethora of quantum phases, such as correlated insulators, superconductivity, magnetism, ferroelectricity, and more. In this talk I will review some of the recent advances in the field, focusing on the newest generation of moiré quantum systems, where correlated physics, superconductivity, and other fascinating phases can be studied with unprecedented tunability. I will end the talk with an outlook of some exciting directions in this emerging field.
Venue and time: 21 May 2025 at 16:15, Lecture Theatre, RDC
Title: New Frontiers in Superconducting Quantum Hardware
Abstract: Superconducting quantum circuits have made impressive advances, yet face core limitations that hinder coherence, reproducibility, and scalability. Chief among these are decoherence from two-level systems (TLS), the variability of amorphous tunnel barriers, and constraints from low-gap superconductors like aluminum. In this talk, I will present our group’s efforts to overcome these challenges by developing a fully niobium-based fabrication process featuring in-situ trilayer Nb/AlO_x/Nb junctions. This approach yields cleaner interfaces, improved junction uniformity, and enables operation at higher frequencies and temperatures thanks to niobium’s larger superconducting gap. These advances directly address the limitations imposed by the low cooling power available at millikelvin temperatures—typically just a few hundred microwatts at 100 mK—by allowing qubit operation closer to 1 K and reducing thermal sensitivity and constraints. We are also pursuing nanobridge junctions as a promising alternative to tunnel junctions, eliminating dielectric barriers and potentially reducing TLS -related loss. Beyond device-level improvements, our fabrication process is designed with scalability and foundry compatibility in mind, supporting reproducible and manufacturable superconducting quantum technologies. Finally, I will highlight our work on integrating control and readout electronics into the cryogenic environment, a key step toward compact, scalable quantum processors. Together, these developments support the global effort to push superconducting qubit platforms beyond current architectural and material limitations, paving the way toward more robust, scalable, and commercially viable quantum computing systems. Target applications include quantum simulation, combinatorial optimization, materials discovery, and fault-tolerant computing.
Venue and time: 07 May 2025 at 16:15 in the Lecture Theatre (RDC)
Title: Quantum Computational Physics
Abstract: Computational physics is shifting from classical computing resources to pivoting towards quantum hardware, allowing for “quantum on quantum” simulations. In this talk we will discuss the “assembler-level” of such quantum computing, asking what kind of quantum many-body phenomena one can induce in digital quantum circuits that employ not only the conventional set of unitary gates, but also mid-circuit measurements and active feedback. In essence, such quantum circuits allow for the dynamical creation, manipulation and decoding of collective entanglement structures. We will discuss quantum criticality in shallow circuits, including Nishimori universality, and map rich phase diagrams through RG flows, supported by simulations on IBM’s 127-qubit quantum processors.
Venue: Small Lecture Theatre
Title: Searching for new physics with ultracold molecules
Abstract: In the Standard Model of particle of physics, the electron has a tiny permanent electric dipole moment (EDM). In most theories that extend the Standard Model, this EDM is predicted to be many orders of magnitude larger due to new CP-violating mechanisms. Thus, EDM measurements are searches for new CP-violating physics which is deeply connected to the puzzle of the matter-antimatter asymmetry of the Universe. The most precise measurements of the electron EDM all use molecules. The molecules are spin polarized, and the EDM determined by measuring the spin precession frequency in an applied electric field. The precession is due to the interaction of the EDM with an effective electric field which can be exceptionally large for heavy polar molecules. To reach high precision we need long spin precession times, which is only possible with neutral molecules if they are cooled to microkelvin temperatures. I will present our efforts to measure the electron EDM using laser-cooled YbF molecules, both in a beam and, in the future, trapped in an optical lattice.
Date:
Wednesday, 19 February, 2025 – 16:30
Venue: Small Lecture Theatre
Title: Exploring Quantum Phases of Matter on Quantum Processors
Abstract: Quantum fluctuations and interactions give rise to exotic phases of matter with remarkable properties, pushing the boundaries of our understanding of many-body quantum systems. Solving these problems is notoriously difficult on classical computers due to the exponential complexity of quantum many-body physics. Quantum processors, however, open new avenues for exploring these systems, offering a direct and potentially transformative approach. In this talk, I will first outline recent progress in realizing and studying topologically ordered and symmetry-protected phases using quantum hardware. I will then discuss their intriguing dynamical properties and how these can reveal quantum phase transitions. Finally, I will introduce a class of novel, highly entangled quantum phases that exist only in non-equilibrium settings and demonstrate how to probe their stability using a quantum processor.
Date:
Wednesday, 5 February, 2025 – 16:30
Venue: Small Lecture Theatre
Title: Porous nitride semiconductors for novel light sources
Abstract: Porous semiconducting nitrides are effectively a new class of semiconducting material, with properties distinct from the monolithic nitride layers from which devices from light emitting diodes (LEDs) to high electron mobility transistors are increasingly made. The introduction of porosity provides new opportunities to engineer a range of properties including refractive index, thermal and electrical conductivity, stiffness and piezoelectricity. Quantum structures may be created within porous architectures and novel composites may be created via the infiltration of other materials into porous nitride frameworks. A key example of the application of porous nitrides in photonics is the fabrication of high reflectivity distributed Bragg reflectors (DBRs) from alternating layers of porous and non-porous GaN. These reflectors are fabricated from epitaxial structures consisting of alternating doped and undoped layers, in which only the conductive, doped layers are electrochemically etched. Conventionally, trenches are formed using a dry-etching process, penetrating through the multilayer, and the electrochemical etch then proceeds laterally from the trench sidewalls. The need for these trenches then limits the device designs and manufacturing processes within which the resulting reflectors can be used. We have developed a novel alternative etching process, which removes the requirement for the dry-etched trenches, with etching proceeding vertically from the top surface through channels formed at naturally-occurring defects in the crystal structure of GaN (see Figure). This etch process leaves an undoped top surface layer almost unaltered and suitable for further epitaxy. This new defect-based etching process provides great flexibility for the creation of a variety of sub-surface porous architectures on top of which a range of devices may be grown. Whilst DBR structures enable improved light extraction from LEDs and the formation of resonant cavities for lasers and single photon sources, recent development also suggests that thick, sub-surface porous layers may enable strain relaxation to help improve the efficiency of red microLEDs for augmented reality displays. Meanwhile, the option of filling pores in nitride layers with other materials provides new opportunities for the integration of nitrides with emerging photonic materials, such as the hybrid-perovskite semiconductors, with perovskites encapsulated in porous nitride layers demonstrating greatly improved robustness against environmental degradation.
Date:
Wednesday, 26 February, 2025 – 16:15
Venue: Small Lecture Theatre
Title: Fermion pairs and loners under the microscope
Date:
Monday, 13 January, 2025 – 15:15
Venue: Small Lecture Theatre
Title: Feeling the strain: quadrupoles, octupoles and beyond
Abstract: Interactions can lead to a wide variety of ordered states in quantum materials, spanning from the obvious to incredibly subtle. For this talk, I will focus on the case of high rank multipole order of local atomic states, which are very much on the subtle end of the spectrum. I will particularly emphasize the importance of coupling to the associated order parameters as a means to measure the multipolar susceptibilities, and also, inside the ordered state, to induce quantum fluctuations via application of transverse effective fields. I will explain the very special roles that strain can play for each of the cases (quadrupolar, octupolar, hexadecapolar), and will outline several new experimental approaches in which the materials ‘feel the strain’ in very different ways. Along the way I will introduce a special case of an electro-nuclear quantum phase transition. The confluence of new measurement techniques and new materials also leads to possibilities for new applications; I will briefly outline one such application, based on a giant elastocaloric effect. Multipolar order, it would seem, is not only interesting from a fundamental perspective, but can also be useful.
Date:
Thursday, 5 December, 2024 – 15:00
Venue: Pippard Lecture Theatre
Title: Strongly correlated topological flat bands in the novel class of moiré materials
Abstract: Twist-angle engineering of 2D materials has led to the recent discoveries of novel many-body ground states in moiré systems such as correlated insulators, unconventional superconductivity, strange metals, orbital magnetism and topologically nontrivial phases. These systems are clean and tuneable, where all phases can coexist in a single device, which opens up enormous possibilities to address key questions about the nature of correlation induced superconductivity and topology, and allows to create entirely novel quantum phases with enhanced interactions. In this talk we will introduce some of the main concepts underlying these systems, concentrating on magic angle twisted bilayer graphene (MATBG) and show how we can engineer strongly interacting, topological and superconducting states. We will further discuss our recent effort to explore the vast library of novel bilayer moiré materials (TMDs etc.) using a novel high-throughput quantum twisted microscope (QTM) technique, which will allow us to search for novel exotic ground states with ever higher interactions energy and temperatures. Last but not least we will show some recent quantum technology developments that were enabled by the ultra-low carrier density superconducting states in MATBG, culminating in the demonstration of highly tuneable single photon detectors.
Date:
Tuesday, 3 December, 2024 – 15:30
Title: Materials for the future
Venue: Pippard Lecture Theatre
Date:
Friday, 22 November, 2024 – 10:30
Title: Searching for topological superconductors using ultrasound
Venue: Small Lecture Theatre
Abstract: For more than a century, superconductors have been the paradigmatic “quantum material”, providing fundamental discoveries like gauge symmetry breaking and impacting technologies from medical imaging to quantum computing. Despite their central importance, characterizing new types of superconductors is still a difficult task: all superconductors have zero resistance, but their more subtle properties related to entanglement and topology are hard to probe experimentally. I will introduce chiral topological superconductors in two dimensions – a type of superconductivity with a “knot” in the superconducting wave function. These superconductors can host Majorana edge modes and bound states in their vortex cores, but finding a real-life example has proven challenging. I will show how we use ultrasound – deforming a crystalline lattice in a manner not unlike how gravity waves deform spacetime – to test whether a particular superconductor has the “right ingredients” to be a 2D topological superconductor. I will present the progress we have made thus far – ruling out many proposed candidate materials and discovering an unexpected new type of superconductivity along the way – and give a prognosis for what I think the most promising route is for discovering a 2D topological superconductor.
Date:
Wednesday, 27 November, 2024 – 10:00
Title: Information scrambling and quantum advantage in quantum simulation
Venue: Small Lecture Theatre
Abstract: There has been impressive recent progress in controlling many-particle quantum systems, ranging from superconducting qubits to neutral atoms in tweezer arrays. In the applications of these systems to both quantum metrology and quantum simulation, there are important questions around how large an entangled many-body state we can usefully and reliably prepare in the presence of decoherence. Entanglement growth is typically limited by Lieb-Robinson bounds on how fast information can spread, so that the useful system size with short-range interactions will grow only linearly with the coherence time of the system. However, for systems with long-range interactions (e.g., atoms in cavities) or movable tweezer arrays, we can engineer so-called fast scrambling dynamics, where information is spread and entanglement is built up on a timescale that grows logarithmically with the system size. I will give an introduction to these ideas and to some of our recent studies of quantum information scrambling, including how transitions to so-called fast scrambling can be observed in neutral atom arrays, with applications in generating useful entangled states for metrology. I will also discuss how this relates to questions of when analogue devices can be quantitatively reliable and operating in regimes that are inaccessible to conventional supercomputers.
Date:
Wednesday, 13 November, 2024 – 16:00
Title: Quantum Sensing of Quantum Matter
Venue: Small Lecture Theatre
Abstract: Important scientific discoveries often happen when scientists have new tools that let them look at complex physical problems in different ways. Recently, there have been exciting breakthroughs in the study of quantum materials. This has led scientists to create new methods for examining their basic qualities. In this talk, Yacoby will discuss some of the recent projects he’s worked on to develop new local quantum sensing techniques. He will also talk about how these techniques can help us better understand quantum materials.
Date:
Tuesday, 12 November, 2024 – 15:00
Title: Flat bands: an obstruction or a resource?
Venue: Small Lecture Theatre
Abstract: The kinetic energy of quantum particles in periodic potentials is characterized by Bloch bands, which give rise to phenomena that differ dramatically from those in free space. Periodic potentials have served as a versatile platform, enabling insights ranging from the behavior of quasiparticles such as holes to the emergence of massless Dirac particles. A particularly intriguing case is that of flat Bloch bands, where quantum interference completely suppresses kinetic mobility. In this colloquium, I will explore how flat Bloch bands dramatically influence well-known phenomena such as Bose-Einstein condensation and superconductivity. I will also discuss recent experimental advancements across various platforms that shed light on these effects.
Date:
Wednesday, 30 October, 2024 – 16:00
Title: Searching for Anyon in Quantum Materials
Venue: Small Lecture Theatre
Abstract: The search for anyons, quasiparticles with fractional charge and exotic exchange statistics, has inspired decades of condensed matter research. Moreover, it has been predicted that exchange braiding of these particles, especially non-abelian anyons, can produce topologically protected logic operations that can serve as building blocks for fault-tolerant quantum computing. In this talk, I will discuss the progress of research on two quantum materials platforms to realize these exotic particles. In the first example, we will discuss anyons arising in fractional quantum Hall (FQH) effects, using quantum Hall interferometers for direct observation of the anyon braiding phase around a confined cavity. In the second example, we will discuss our recent experimental efforts to realize non-abelian anyons in proximitized topological insulator surfaces by controlled manipulation of magnetic vortices containing non-abelian anyons.
Date:
Friday, 18 October, 2024 – 15:00
Title: Visualizing strongly interacting quantum phases of matter
Venue: Small Lecture Theatre
Abstract:
When electrons are forced to interact strongly with each other, some of the most exotic electronic phases and novel quasiparticles can emerge. A key approach to force electrons to strongly interact with one another is to confine them to energy bands with no momentum dispersion, i.e. flat bands. Flat bands can be realized in two-dimensional materials in a high magnetic field or in newly discovered moiré materials in which quantum interference can give rise to flat energy bands. The journey of exploring old and new flat bands, using high resolution quantum microscopy, has taken us from confirming some of the earliest predictions for correlated phases of matter (such as formation of Wigner crystal), to new approaches to probe novel quantum phases that host exotic quasiparticles that are neither bosons or fermions. These quantum phases may play a key role in the future of quantum computing by providing an approach to build topological qubits. I’ll describe how a combination of imaging electronic states on the nanoscale and building structures from two-dimensional materials and their stacks may make building such qubits possible.
Date:
Wednesday, 16 October, 2024 – 09:30