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We study quantum compression and decompression of light pulses that carry quantum information using a photon-echo quantum memory technique with controllable inhomogeneous broadening of an isolated atomic absorption line. We investigate media with differently broadened absorption profiles, transverse and longitudinal, finding that the recall efficiency can be as large as unity and that the quantum information encoded into the photonic qubits can remain unperturbed. Our results provide new insight into reversible light-atom interaction, and are interesting in view of future quantum communication networks, where pulse compression and decompression may play an important role to increase the qubit rate, or to map quantum information from photonic carriers with large optical bandwidth into atomic memories with smaller bandwidth.
The future of long-distance quantum communication relies on the availability of quantum memory, i.e. devices that allow temporal storage of quantum information. We review research related to quantum state storage based on a photon-echo approach in rare earth ion doped crystals and glasses.
Quantum memory is a key element for quantum repeaters and linear optical quantum computers. In addition to memory, repeaters and computers also require manipulating quantum states by means of unitary transformations, which is generally accomplished u
We report the fabrication and characterization of a Ti$^{4+}$:Tm$^{3+}$:LiNbO$_3$ optical waveguide in view of photon-echo quantum memory applications. In particular, we investigated room- and cryogenic-temperature properties via absorption, spectral
In this book chapter we review photon echo based schemes for optical quantum memory. We outline the basic principles of the Atomic Frequency Comb (AFC), Gradient Echo Memory (GEM) and Rephased Amplified Spontaneous Emission (RASE) protocols. We descr
We propose a new quantum numerical scheme to control the dynamics of a quantum walker in a two dimensional space-time grid. More specifically, we show how, introducing a quantum memory for each of the spatial grid, this result can be achieved simply