Theory

Long Term Goals
Our long term goals are to investigate and probe the universality of quantum physics. How large can an object be and still behave quantum mechanically? Is there a convenient description of quantum physics that treats space and time on an equal footing? How do we witness quantum features in complex systems such as the biological living ones? How can we devise physical laws that can describe generalisations of quantum systems?
We look at a broad range of topics related to quantum theory, from the microscopic scale to the rest of the universe and beyond. A selection of our current topics of interest are outlined below.

 

Quantum Algorithms and Quantum Computational Complexity
We work on the topic of verification in quantum cryptography. Say we have a network of parties sharing an untrusted quantum state that they want to use for some protocol. Here the research focuses on secure ways of testing this state that work even if some of the parties or their measurement devices are malicious. We apply these techniques to build ‘verified’ versions of protocols such as teleportation, anonymous transmission and computation.

 

Many-body Correlations 

ghz

Many-body correlations...

Quantum Information Theory in High Energy Physics

 

In particular, quantum chaos and information scrambling. We are investigating quantum gravitational effects at the cosmological level in the early universe during its inflationary phase. A related theme is the application of entanglement witnesses in multipartite systems to cosmological observables like the CMB to derive bounds on quantum effects.

 

Thermodynamics

maxwell

The theory of heat and work

Quantum Thermodynamics and Resource Theory

 

We are looking into the use of indefinite causal ordered operations in a quantum thermodynamics context, with goals of developing a thermodynamic resource theory including these operations and looking into their application in quantum thermodynamic work cycles.

 

 

 

 

 

Foundations

tetra

Why is the universe the way it is?

Constructor theory

 

We are interested in formulating guiding principles to inform the search for future theories of physics, which will supersede quantum theory. Specifically, we are focusing on Constructor Theory (CT). In CT, laws are expressed solely as constraints on what transformations are possible, what are impossible, and why. One of CT’’s main aim is to provide general principles applicably to a vast class of theories (including quantum theory), and to any scale, generalising and supplementing existing principles (e.g. those of thermodynamics or quantum information theory). This is expected to provide new predictions probing regimes so far unexplored.

Open Quantum Systems

polaron

Open Quantum Systems

The Physics of Fermions and Beyond
Also of interest are the concept of correlation and entanglement in fermionic quantum systems, reduced density matrix functional theory (RDMFT), numerical methods for strongly correlated electrons in general, Bose-Einstein condensation in systems of hard-core bosons, generalized Pauli constraints.