ERC FUNDED PROJECTS

Active Matter systems, such as self-propelled colloids, violate time-reversal symmetry by producing entropy locally, typically converting fuel into mechanical motion at the particle scale. Other driven systems instead produce entropy because of global forcing by external fields, or boundary conditions that impose macroscopic fluxes (such as the momentum flux across a fluid sheared between moving parallel walls). Nonequilibrium statistical physics (NeSP) is the basic toolbox for both classes of system. In recent years, much progress in NeSP has stemmed from bottom-up work on driven systems. This has provided a number of exactly solved benchmark models, and extended approximation techniques to address driven non-ergodic systems, such as sheared glasses. Meanwhile, work on fluctuation theorems and stochastic thermodynamics have created profound, model-independent insights into dynamics far from equilibrium. More recently, the field of Active Matter has moved forward rapidly, leaving in its wake a series of generic and profound NeSP questions that now need answers: When is time-reversal symmetry, broken at the microscale, restored by coarse-graining? If it is restored, is an effective thermodynamic description is possible? How different is an active system's behaviour from a globally forced one? ADSNeSP aims to distil from recent Active Matter research such fundamental questions; answer them first in the context of specific models and second in more general terms; and then, using the tools and insights gained, shed new light on longstanding problems in the wider class of driven systems. I believe these new tools and insights will be substantial, because local activity takes systems far from equilibrium in a conceptually distinct direction from most types of global driving. By focusing on general principles and on simple models of activity, I seek to create a new vantage point that can inform, and potentially transform, wider areas of statistical physics.

2 043 630 €

Start date: 2017-10-01, End date: 2022-09-30

AQSuS aims at experimentally implementing analogue quantum simulation of interacting spin models in two-dimensional geometries. The proposed experimental approach paves the way to investigate a broad range of currently inaccessible quantum phenomena, for which existing analytical and numerical methods reach their limitations. Developing precisely controlled interacting quantum systems in 2D is an important current goal well beyond the field of quantum simulation and has applications in e.g. solid state physics, computing and metrology. To access these models, I propose to develop a novel circuit quantum-electrodynamics (cQED) platform based on the 3D transmon qubit architecture. This platform utilizes the highly engineerable properties and long coherence times of these qubits. A central novel idea behind AQSuS is to exploit the spatial dependence of the naturally occurring dipolar interactions between the qubits to engineer the desired spin-spin interactions. This approach avoids the complicated wiring, typical for other cQED experiments and reduces the complexity of the experimental setup. The scheme is therefore directly scalable to larger systems. The experimental goals are: 1) Demonstrate analogue quantum simulation of an interacting spin system in 1D & 2D. 2) Establish methods to precisely initialize the state of the system, control the interactions and readout single qubit states and multi-qubit correlations. 3) Investigate unobserved quantum phenomena on 2D geometries e.g. kagome and triangular lattices. 4) Study open system dynamics with interacting spin systems. AQSuS builds on my backgrounds in both superconducting qubits and quantum simulation with trapped-ions. With theory collaborators my young research group and I have recently published an article in PRB [9] describing and analysing the proposed platform. The ERC starting grant would allow me to open a big new research direction and capitalize on the foundations established over the last two years.

1 498 515 €

Start date: 2017-04-01, End date: 2022-03-31

Atomic scale defects play a key role in determining the behaviour of all crystalline materials, profoundly modifying mechanical, thermal and electrical properties. Many current technological applications make do with phenomenological descriptions of these effects; yet myriad intriguing questions about the fundamental link between defect structure and material function remain. Transmission electron microscopy revolutionised the study of atomic scale defects by enabling their direct imaging. The novel coherent X-ray diffraction techniques developed in this project promise a similar advancement, making it possible to probe the strain fields that govern defect interactions in 3D with high spatial resolution (<10 nm). They will allow us to clarify the effect of impurities and retained gas on dislocation strain fields, shedding light on opportunities to engineer dislocation properties. The exceptional strain sensitivity of coherent diffraction will enable us to explore the fundamental mechanisms governing the behaviour of ion-implantation-induced point defects that are invisible to TEM. While we concentrate on dislocations and point defects, the new techniques will apply to all crystalline materials where defects are important. Our characterisation of defect structure will be combined with laser transient grating measurements of thermal transport changes due to specific defect populations. This unique multifaceted perspective of defect behaviour will transform our ability to devise modelling approaches linking defect structure to material function. Our proof-of-concept results highlight the feasibility of this ambitious research project. It opens up a vast range of exciting possibilities to gain a deep, fundamental understanding of atomic scale defects and their effect on material function. This is an essential prerequisite for exploiting and engineering defects to enhance material properties.

1 610 231 €

Start date: 2017-03-01, End date: 2022-02-28

Amine containing compounds are ubiquitous in everyday life and find applications ranging from polymers to pharmaceuticals. The vast majority of amines are synthetic and manufactured on large scale which creates waste as well as requiring high temperatures and pressures. The increasing availability of biocatalysts, together with an understanding of how they can be used in organic synthesis (biocatalytic retrosynthesis), has stimulated chemists to consider new ways of making target molecules. In this context, the iterative construction of C-N bonds via biocatalytic hydrogen borrowing represents a powerful and unexplored way to synthesise a wide range of target amine molecules in an efficient manner. Hydrogen borrowing involves telescoping redox neutral reactions together using only catalytic amounts of hydrogen. In this project we will engineer the three key target biocatalysts (reductive aminase, amine dehydrogenase, alcohol dehydrogenase) required for biocatalytic hydrogen borrowing such that they possess the required regio-, chemo- and stereo-selectivity for practical application. Recently discovered reductive aminases (RedAms) and amine dehydrogenases (AmDHs) will be engineered for enantioselective coupling of alcohols (1o, 2o) with ammonia/amines (1o, 2o, 3o) under redox neutral conditions. Alcohol dehydrogenases will be engineered for low enantioselectivity. Hydrogen borrowing requires mutually compatible cofactors shared by two enzymes and in some cases will require redesign of cofactor specificity. Thereafter we shall develop conditions for the combined use of these biocatalysts under hydrogen borrowing conditions (catalytic NADH, NADPH), to enable the conversion of simple and sustainable feedstocks (alcohols) into amines using ammonia as the nitrogen source. The main deliverables of BIO-H-BORROW will be a set of novel engineered biocatalysts together with redox neutral cascades for the synthesis of amine products from inexpensive and renewable precursors.

2 337 548 €

Start date: 2017-06-01, End date: 2022-05-31