#	Pagina
attuale pagina	/open-h2020/projects/215640/results.html

Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - RydSpin (Nonequilibrium many-body spin dynamics in strongly interacting Rydberg systems)

Teaser

Summary

Dipolar interactions between electron spins affect magnetic properties of matter on microscopic and macroscopic scales. An understanding of dynamical quantum magnetism enables researchers to explain behaviors of magnetic materials, which lead to a development of technology related to condensed matter physics. However, there are still open questions about how a non-equilibrium spin system evolve in the presence of disorder and long-range interactions. The description of this evolution is generally difficult to achieve because of the complexity in the preparation of large samples with fully control in states and experimental conditions. In this work, we used Rydberg-spin systems to study non-equilibrium many-body spin dynamics. With an ability to fully control the spin state and spin interactions, the work uncovered the relaxation dynamics and reveal the evolution of the spin systems. The techniques implemented in this work including state-selective detection as well as precise microwave control for spin manipulation can be advantageous for other research groups that utilize spin systems to study magnetism as well as condensed matter physicists.

Work performed

State-selective field ionization: We have designed and constructed a high-voltage amplifier circuits together with a software to generate a controllable high voltage signal for ionizing Rydberg atoms. The population of each Rydberg-spin state in the system can then be extracted simultaneously. Ion signals from two spin states resulting from state-selective field ionization is shown in Figure 1.

Quantum phases of the spin system: We have designed a microwave focusing scheme to confine our microwave field into our experimental chamber as shown in Figure 2. This results in more than 100 times higher microwave power, which allows us to apply short microwave pulse (nanosecond) for spin-state manipulation. The resulting Rabi frequency obtained from microwave focusing scheme.

Thermal equilibrium of the spin system: We have developed microwave pulse sequences to modify interactions of our spin system. This helps us to study spin dynamics with a full control of Hamiltonian. We have performed numerical simulation to extract the dynamics of the system.

The work related to this project results in two Master theses supervised by the fellow. This work has been disseminated locally and worldwide through conferences and academic visits.

Final results

In addition to tune the spin interaction by using different Rydberg spin states or by controlling interatomic separation, we have developed a technique to design or modify the interaction of the system using microwave pulse sequences which has been utilized in Nuclear Magnetic Resonance (NMR). This technique is developed beyond the limit of NMR in which it is generalized to be able to use with all type of spin interaction available in Rydberg systems.