Experimental demonstration of quantum memory for light

By B. Julsgaard, Jacob Friis Sherson, J. I. Cirac, Jaromír Fiurásek, Eugene Simon Polzik. Nature, 2004

674 citations recorded by the source corpus.

The information carrier of today's communications, a weak pulse of light, is an intrinsically quantum object. As a consequence, complete information about the pulse cannot be perfectly recorded in a classical memory, even in principle. In the field of quantum information, this has led to the long-standing challenge of how to achieve a high-fidelity transfer of an independently prepared quantum state of light onto an atomic quantum state. Here we propose and experimentally demonstrate a protocol for such a quantum memory based on atomic ensembles. Recording of an externally provided quantum state of light onto the atomic quantum memory is achieved with 70 per cent fidelity, significantly higher than the limit for classical recording. Quantum storage of light is achieved in three steps: first, interaction of the input pulse and an entangling field with spin-polarized caesium atoms; second, subsequent measurement of the transmitted light; and third, feedback onto the atoms using a radio-frequency magnetic pulse conditioned on the measurement result. The density of recorded states is 33 per cent higher than the best classical recording of light onto atoms, with a quantum memory lifetime of up to 4 milliseconds.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/65d2c0afae30dbb6b1c7c5b479760b45b846f41e

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Artificial Intelligence

In Atomic and Molecular Physics, and Optics

Citations in the corpus

A millisecond quantum memory for scalable quantum networks (2008, background): “Although atomic memories for classical lights[8] and continuous variables[9] have been demonstrated with milliseconds storage time, there is no equal advance in the development of quantum memory for single excitations, where only around 10 μs storage time was achieved[10, 11, 12, 13].”
The security of practical quantum key distribution (2008, methodology): “Experiments are being pursued using several techniques, like atomic ensembles (Chou et al., 2007; Julsgaard et al., 2004), NV centers (Childress et al., 2006), doped crystals (Alexander et al., 2006; Staudt et al., 2007).”
Towards high-speed optical quantum memories (2009, background): “Memories based on measurement and feedback have also been develope”
Linear optical quantum computing with photonic qubits (2005, background): “Using the magnetic sublevels of the ground state of an atomic ensemble, Julsgaard et al. (2004) stored a weak coherent light pulse for up to 4 ms with a fidelity of 70%.”
Optical quantum memory (2009, methodology): “[138] using experimental tools developed earlier by the same group for the purpose of entangling two atomic ensembles [139].”
Quantum interface between light and atomic ensembles (2008, methodology): “The latter was the case of the experiments by Julsgaard et al. (2001, 2004a) and Sherson et al. (2006a), where pulses of about 1 msec duration have been used.”
Developments in alkali -metal atomic magnetometry (2008, background): “, 2003), quantum memory (Julsgaard et al., 2004), and slow light experiments (Klein et al.”
Storage and retrieval of single photons transmitted between remote quantum memories (2005, background): “2 The potential of atomic ensembles to serve as quantum memories has recently attracted considerable attention [1, 2, 8, 9, 10, 11], spawning two distinct lines of research.”
Multiphoton entanglement and interferometry (2008, background): “…2001; Duan, Cirac, and Zoller, 2002; Chen et al., 2007), and the relevant experimental advances (Kash et al., 1999; Phillips et al., 2001; Liu et al., 2001; Schori et al., 2002; Julsgaard et al., 2004; van der Wal et al., 2003; Bajcsy et al., 2003; Matsukevich and Kuzmich; 2004) are significant.”
Quantum Secure Direct Communication with Quantum Memory. (2016, background): “However, for a practical application, a quantum memory is greatly needed because it is robust against decoherence and convertible to quantum states of light on demand [21-26], which indicates effective control for transferring a message in the time domain, therefore a delay line is only suitable for”