
Alex Retzker
Krill Prize 2015
Hebrew University

Alex Retzker
Research Topic:
Quantum Technologies
My current research interests are focused in the fields of quantum optics and quantum technologies. In particular, I am interested in theory which is strongly connected to experiments and I am actively pursuing collaborations with experimentalists.
This relation between theory and experiment manifests itself in dealing with theoretical schemes which help in realising quantum information objectives, like quantum processing and quantum simulation. Moreover, I am interested in applying quantum information ideas to the benefit of other areas of physics such as novel ideas for quantum sensing, to name one example. The field of quantum technologies has dramatically developed in recent years both theoretically and experimentally and the scope of quantum technology exploration has naturally extended to many areas of physics, including atomic physics, condensed-matter and quantum field theory. I have worked on several of these areas of quantum technologies, specifically, NV centres in diamond, linear ion traps, BECs, condensed matter systems and entanglement in quantum field theory. I used tools and concepts from quantum entanglement to study the structure of the vacuum state of quantum field theories, to obtain a better understanding of condensed matter properties and to design novel laser cooling schemes and quantum sensing protocols. I have always been driven by realistic experimental conditions, and this has motivated my collaborations with experimentalists. These collaborations have led to the proposal of novel schemes which many of them are now being realised by experimental teams. In the following I present briefly the current state of my research.
Quantum sensing—The ability to sense and image minute magnetic and electric fields with atomic scale resolution is one of the major challenges of modern science and technology and may have profound impact on medicine, biology, chemistry, physics and material science. The basic units of magnetic moments in nature are the dipole moments associated with the spin of nuclei and single electrons. Large part of my research is aimed at detecting these single spins at ambient conditions with the goal to revolutionise the state of the art to create novel sensing technologies that provide unprecedented access and insight into the structure and function of individual bio-molecules under physiological conditions and apply these to the observation of biological processes down to the quantum level and with atomic resolution. The proposed spin-microscopy can be used to understand and appreciate the molecular structure and dynamics of individual specimens under physiological conditions. The ability to observe single molecules overcomes a key limitation of liquid state NMR and X-Ray based structure determinationprotocols. In order to achieve this I am concentrating on the NV centre in diamond which is the most promising candidate to realise this goal. The broad challenges that this ambitious programme presents must be tackled by scientists with broad expertise and thus I am collaborating with many groups worldwide. In the past year, since I had arrived in Jerusalem, I have recruited seven research students and postdocs when four of them are working full time on this project and the other three invest part of their time on these goals. I anticipate that in the next few years a large part of my group will work on this subject. Quantum simulations—Various systems have been proposed for the realisation of a quantum computer, including trappedions, optical lattices, linear optics and solid state devices. However, despite enormous experimental progress, due to the high degree of precision that is required, the realisation of a large scale quantum computer is still not within reach. Instead, the realisation of quantum simulators which are much less demanding have recently become a target of growing interest. I have helped to drive the development of this growing field with several significant contributions. Since I came to Jerusalem, in the past year, I have had a few contributions in the field, mostly on the subjects of the study of nonlinear physics and topological defects in particular, and in the study of frustrated spin models. I have concentrated on NV centres in diamond and trappedions. Despite the fact that these are recent proposals, many of these contributions were realised and others are being currently pursued. Two members of my group are working on this subject. Robust operations — In the past two years I got interested in the field of dynamical decoupling and error correction, in particular, in the utilisation of these methods for the benefit of quantum computing and quantum sensing. In the quantum computing part I had a few contributions which had drawn a lot of interest by the ion trap and NV community. In particular the ion trap proposal was realised by the group of Dave Wineland, the last year Nobel laureate, who realised one of my proposals for a robust quantum gate and has achieved a record breaking fidelity. I believe that this novel gate scheme would be used by many other groups in the next few years. Currently, one member of my group is working on this subject.
