I am interested in quantum information and quantum foundations, and their intersection. All modern computers utilise quantum physics to store information, but the description of the information is not quantum at all. For quantum information, both the storage medium and the information itself has a quantum description. I am interested in how quantum information is fundamentally different from its non-quantum counterpart and how this can be used in information processing tasks, especially those relevant to cryptography and the verification of quantum devices. I also have side interests in quantum computational complexity (especially the complexity of low-depth quantum circuits and non-circuit-based models of quantum computing such as measurement-based quantum computing) and post-quantum cryptography (standard cryptography but assuming certain problems are hard even for a quantum computer).
Very recently, I have been working on the following:
Self-testing: this is when we have black-box access to a (potentially quantum) device and by interacting with it, try and determine its quantum characteristics, if that's possible. In a recent paper we showed that we can determine (up to some symmetries) the quantum state of an arbitrary number of systems.
Resource theories for non-classicality: non-classical phenomena can be seen as a resource in many information processing tasks, so we would like tools to be able to quantify and characterise this resource. In a couple of recent papers we should how to do this for a particular kind of non-classical resource in scenarios related to "Einstein-Podolsky-Rosen steering".
- Quantifying EPR: the resource theory of nonclassicalist of common-cause assemblages, Beata Zjawin et al (2023)
- The resource theory of nonclassicality of channel assemblages, Beata Zjawin et al (2023)
Computational hardness of estimating entropy and entanglement: not only do we want to identify non-classicality such as "quantum entanglement", we would like to identify it efficiently. One way of doing this is through estimating the entropy produced by sub-systems of an entangled system (called the entanglement entropy). Current quantum technologies typically allow for quite low-depth quantum circuits before the quantum systems become noisy and useless. Thus we are interested in determining the non-classicality of low-depth quantum circuits. With Andru Gheorghiu we showed that this problem is hard even for a quantum computer assuming learning with errors is hard for a quantum computer (an assumption underpinning many schemes in post-quantum cryptography).
Before this, I have worked on quantum non-locality and non-local games, certifiable quantum randomness generation, computation in general physical theories, and measurement-based quantum computation.
Prior to joining the CS Department I was a senior research scientist in quantum cryptography at Quantinuum, a multi-national quantum computing company. Before working in industry I have held various researcher and lecturer positions at the University of Oxford, University of Edinburgh, ICFO-Institute of Photonic Sciences (Barcelona) and the University of London. I have an undergraduate degree from Imperial College London and my PhD in quantum computing is from UCL.