Entangled Rydberg matter for quantum sensing and simulations

Lead Research Organisation: University of Nottingham
Department Name: Sch of Physics & Astronomy


Owed to their remarkable properties trapped Rydberg atoms and ions are ideal systems for realizing quantum simulators and sensors. The strong and long-ranged dipolar interactions between Rydberg matter is the basis for entangling gates. The long lifetime of circular Rydberg states leads to long coherence times, enabling gates with high fidelity and quantum simulation over long times. Large transition dipole moments make Rydberg atoms and ions highly sensitive to electric fields, microwave and terahertz radiation.

In this project, we will exploit these unique physical features to build two devices: A Rydberg quantum simulator and a Rydberg-enabled quantum sensor. In particular, we will realize quantum gates based on dipolar Rydberg interaction, and bring their performance to a new level using coherent control methods. We will employ dipolar interactions for realizing quantum simulators and apply them to simulate coupled spin and spin-boson systems through digital and analogue approaches. This will enable the investigation of quantum-controlled structural phase transitions as well as the simulation of the motional mode structure of molecules. We will develop highly sensitive probes for electric fields and microwave radiation based on Rydberg-excited ions that can be positioned with nanometer precision and cooled down to micro-Kelvin temperature. This will enable local measurements of electric and microwave fields with high sensitivities that will be further improved through the use of entangled quantum states and dynamical decoupling schemes. Our research will deliver the enabling steps for a future Rydberg-enhanced quantum technology base thereby securing the competitiveness of the European Research Area.

Planned Impact

In this project, we will significantly advance the state-of-the-art of quantum sciences and technology by delivering Rydberg enhanced quantum simulators and quantum sensing devices. We will develop reliable technology for the different components of these systems and thereby gain a deeper fundamental and practical understanding of Rydberg enhanced quantum simulation and sensing protocols as well as their implementation. This will not only generate impact within the physics community, but may achieve new capabilities also in other related fields such as biology and chemistry.

(1) Development of Quantum simulators using Rydberg interactions.
Quantum simulator platforms will yield powerful tools for the understanding of collective phenomena in chemistry, physics and biology that are currently inaccessible for direct investigation, and too complex to be simulated on any classical computer. Specifically, the quantum simulators developed in ERyQSenS will deliver two key breakthroughs: (i) A quantum simulator that for the first time enables strong interactions and extremely long lifetimes. This will enable the simulation of long-time phenomena, such as equilibration and thermalization - phenomena that are inaccessible by current simulation platforms. This will shed new light on important problems, such as the emergences of irreversible thermodynamics from reversible quantum processes, metastability and (quantum) glassiness. (ii) A quantum simulator that for the first time allows the exploration of strongly coupled electronic and vibrational degrees of freedom for the simulation of molecular dynamics and the realization of open spin systems with tailored dissipation. This will pave the way for the study and optimization of excitation transfer processes, with relevance in chemistry and biology.

(2) Building of Quantum sensors with Rydberg atoms and ions.
The Rydberg quantum sensors developed within ERyQSenS will form devices for the characterization of surface effects, for precision sensing of local electric and microwave fields as well as for enhanced terahertz spectroscopy and imaging. The availability of such sensors will be of practical relevance and generate impact in a number of fields, ranging from surface science, biology, medicine, and astronomy to security systems. The underlying technological platform, which consists of Rydberg ions coupled to microwave fields on a chip will advance the state-of-the-art in hybrid-systems research. This development will enable new hybrid quantum devices, such as quantum transducers or quantum information processing architectures that rely on linking trapped ions and superconducting qubits via microwave photons.
The technologies developed in ERyQSenS are thus expected to impact broadly in the academic sector. Due to the broad relevance of quantum simulation and sensing this will enhance interdisciplinary in crossing traditional boundaries between disciplines. We expect the proof-of-principle experiments conducted within ERyQSenS to constitute the starting point of a future commercialization process.

(3) Training of new experts and fostering new research leaders.
Doctoral students and postdocs involved in ERyQSenS will have the opportunity to become experts at an interface of Rydberg physics, quantum sensing, quantum simulations, and quantum optics. The training of skilled young scientists in the implementation of this new quantum technology will be a lasting investment in the leadership of Europe in this hot new field of research. Moreover, ERyQSens gives a platform for leadership to several young scientists (Dr. Weibin Li, leader of UN, Dr. Peter Ivanov, leader of SOF, Dr. Cle'ment Sayrin at LKB). At a consolidation stage of their career, they have the opportunity to become new highly visible actors in this field by taking responsibilities in a high-level international network, backed-up by the experience of senior experts in the consortium.
Description Quantum computation with trapped Rydberg calcium ions 
Organisation Johannes Gutenberg University of Mainz
Department Institute of Molecular Biology (IMB), Mainz, Germany
Country Germany 
Sector Academic/University 
PI Contribution We have theoretically explored Rydberg excitation spectra of trapped calcium ions, predicted that structural phase transition of ion crystals can be induced by Rydberg excitation, and proposed a scheme to realize parallel quantum gates using Rydberg states.
Collaborator Contribution The experimental group had experimentally studied coherent Rydberg excitation of calcium ions in a linear Paul trap for the first time. This opens new opportunities to build fast quantum gates with Rydberg interactions.
Impact 1. Weibin Li and Igor Lesanovsky, Electronically Excited Cold Ion Crystals, Phys. Rev. Lett. 108, 023003 (2012). 2. Weibin Li, Alexander W. Glaetzle, Rejish Nath, and Igor Lesanovsky, Parallel execution of quantum gates in a long linear ion chain via Rydberg mode shaping, PHYSICAL REVIEW A 87, 052304 (2013). 3. F Schmidt-Kaler, T Feldker, D Kolbe, J Walz, M Mu¨ller, P Zoller, W Li and I Lesanovsky, Rydberg excitation of trapped cold ions: a detailed case study, New Journal of Physics 13 075014 (2011). 4. Weibin Li and Igor Lesanovsky, Entangling quantum gate in trapped ions via Rydberg blockade, Appl. Phys. B 114, 37 (2014).
Start Year 2011
Description Theory and experiment collaboration on trapped Rydberg Strontium ions 
Organisation Stockholm University
Department Department of Physics
Country Sweden 
Sector Academic/University 
PI Contribution We have theoretically explored properties of trapped strontium ions in Rydberg states. Through large scale numerical simulations, we have predicted dynamical behaviors of single and multiple trapped Rydberg ions in a linear Paul trap. We have developed a theory to explain experimental results. Besides, we have proposed schemes to build entangled quantum gates with trapped Rydberg ions.
Collaborator Contribution The Stockholm group had made significant achievement in the experimental realisation of trapped Rydberg ions. In the collaboration, they have experimentally observed the Rydberg S and D states. The theory and experimental data agree very well.
Impact Publication resulted from this collaboration: Gerard Higgins, Weibin Li, Fabian Pokorny, Chi Zhang, Florian Kress, Christine Maier, Johannes Haag, Quentin Bodart, Igor Lesanovsky, and Markus Hennrich,Single Strontium Rydberg Ion Confined in a Paul Trap, Phys. Rev. X 7, 021038 (2017).
Start Year 2015
Description consortium workshop 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact 15 participates attended the kick-off meeting at Stockholm University. Current status of the consortium was presented. Open questions and new ideas were discussed thorougly. Plans on future research activities were made.
Year(s) Of Engagement Activity 2018