On-demand solid-state quantum memory for time-bin qubits*
Cavendish Laboratory, University of Cambridge
Özet: Optical quantum memories (QMs) are one of the fundamental building blocks in quantum information science (QIS) where reversible mapping of the state of light to matter is of great importance. They might find important use in quantum communication and computation applications. On the other hand, rare-earth ions (REIs) have been investigated for decades for their optical properties. They exhibit excellent coherence properties when cooled down to cryogenic temperatures. Not surprisingly, they emerged as a promising candidate for use in QIS as QMs.
In this talk I will explain our experiments with REIs on realizing the first spin-wave quantum memory for time-bin qubits [1,2]. We make use of the atomic frequency comb protocol and reach a signal-to-noise ratio (SNR) of >10 for input pulses with mean photon numbers of about 1. The high SNR then allowed us to store and on-demand retrieve time-bin qubits encoded with weak coherent pulses. We obtained storage fidelities of around 90% which is higher than values achievable by any known classical strategy, thus proving the quantum character of our device.
*Work performed at ICFO – The Institute of Photonic Sciences, Barcelona.
 M. Gündoğan, M. Mazzera, P.M. Ledingham, M. Cristiani and H. de Riedmatten, Coherent storage of temporally multimode light using a spin-wave atomic frequency comb memory, New J. Phys. 15, 045012 (2013).
 M. Gündoğan, P.M. Ledingham, K. Kutluer, M. Mazzera, and H. de Riedmatten, Solid State Spin-Wave Quantum Memory for Time-Bin Qubits, Phys. Rev. Lett. 114, 230501 (2015).
Tarih : 24 Aralık 2015 Perşembe, Saat: 15:00
Yer : MSGSÜ Bomonti Yerleşkesi, Fizik Bölümü