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Q: Fachverband Quantenoptik und Photonik
Q 29: Quantum Optics and Photonics I
Q 29.3: Vortrag
Dienstag, 6. März 2018, 14:30–14:45, K 0.016
Subradiant states in many-body quantum systems for excitation storage — •Jemma Needham1,2 and Beatriz Olmos1,2 — 1Centre for the Mathematics and Theoretical Physics of Quantum Non-Equilibrium Systems, University of Nottingham, University Park, Nottingham, NG7 2RD, UK. — 2School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
Many-body quantum systems are currently of great interest due to increased developments in quantum computation. We explore the dynamics associated with a 1D chain of atoms excited to low-lying states, limited to a single excitation within the system. The atoms are closely spaced such that the system enters a regime exhibiting collective behaviour. In particular, we are interested in the subradiant state that arises when an atomic chain is initialised with a single excitation at one end and then allowed to evolve. Subradiant states decay very slowly, if at all, and hence this system could find applications as a quantum memory. We derive expressions for long-range coupling between pairs of atoms and collective dissipation that occur due to small atomic spacing. We then develop a protocol to initialise an excited state, and we store the excitation for timescales much longer than those occurring naturally. This protocol allows natural evolution from a relatively simple initial state, into a slowly decaying state which could be utilised in the storage of quantum information. We finally explore the properties of the possible stored states, and gain further understanding on the system's time evolution.