Quantum Memory for Squeezed Light

Appel, J.; Figueroa, Eden; Korystov, Dmitry; Lobino, Mirko; Lvovsky, A. I.

doi:10.1103/physrevlett.100.093602

Cited by 369 publications

(355 citation statements)

References 32 publications

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“…For both plots, the less (red) and larger (blue) fluctuating lines correspond to the cases where the optimal feedback control is performed or not, respectively. The error bars show the standard deviation of the estimation error, which is calculated from the solution to the Riccati equation (19). The parameters are taken as µ = −0.4 and r = 10 −9 , which were shown in Fig.…”

Section: Fig 4: (Color Online)mentioning

confidence: 99%

“…Candidates for a memory are largely divided into two categories: discrete variable systems such as an atom with distinct energy levels [1,2,3,4,5,6,7,8,9,10,11,12,13] and continuous variable systems such as an opto-mechanical oscillator with a vibration mode [14,15,16,17,18,19,20,21,22]. Remarkably, some experimental demonstrations of quantum state transfer have been reported [1,8,16,18,19].…”

Section: Introductionmentioning

confidence: 99%

“…Transferring a quantum state of light to a memory is of particular importance for various purposes in quantum information technologies [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22]. Candidates for a memory are largely divided into two categories: discrete variable systems such as an atom with distinct energy levels [1,2,3,4,5,6,7,8,9,10,11,12,13] and continuous variable systems such as an opto-mechanical oscillator with a vibration mode [14,15,16,17,18,19,20,21,22].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dynamical Gaussian state transfer with quantum-error-correcting architecture

Tajimi

Yamamoto

2012

Phys. Rev. A

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Transferring a quantum state of a light field to a memory is of particular importance. However, this transfer is usually hampered because the memory system is subjected to some noise and this can limit the performance of the state transfer to a great extent. In this paper, we consider the transfer of a Gaussian state of light to a linear medium memory such as an opto-mechanical oscillator and propose a dynamical feedback controller that suppresses the noise in the memory system. To protect an unknown state, the feedback scheme employs the specific configuration of the quantum error correction; that is, a three-mode Gaussian state having appropriate syndromes is taken as the input. Correspondingly, the memory consists of three independent linear systems. The syndrome errors are estimated continuously in time through the measurement of the output field, and the results are then fed back to control the system. Because the input is Gaussian and the systems are all linear, it is possible to formulate the problem using the framework of the celebrated classical Kalman filtering and linear quadratic Gaussian control. A numerical simulation demonstrates the effectiveness of the control scheme.

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Section: Fig 4: (Color Online)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamical Gaussian state transfer with quantum-error-correcting architecture

Tajimi

Yamamoto

2012

Phys. Rev. A

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“…The main objective is to store and retrieve light pulses or photons without destroying their quantum state, that is the system should be able to store at the same time two on commuting variables like the two quadratures of a light pulses and allow for their retrieval. Mapping quantum states of light like single photons or qubits [7][8][9], coherent light pulses without noise added [10] and squeezed light [11,12] onto long lived states of atomic coherence has been first experimentally investigated in alkali-metal gases. More recently quantum memory for entangled photons have been demonstrated in rare-earth doped crystals [13,14].…”

Section: Introductionmentioning

confidence: 99%

High-speed spatially multimode atomic memory

et al. 2011

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We study the coherent storage and retrieval of a very short multimode light pulse in an atomic ensemble. We consider a quantum memory process based on the conversion of a signal pulse into a long-lived spin coherence via light matter interaction in an on-resonant Λ -type system. In order to study the writing and reading processes we analytically solve the partial differential equations describing the evolution of the field and of the atomic coherence in time as well as in space. We show how to optimize the process for writing as well as for reading. If the medium length is fixed, for each length, there is an optimal value of the pulse duration. We discuss the information capacity of this memory scheme and we estimate the number of transverse modes that can be stored as a quantum hologram.

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“…This makes homodyne characterization more precise but also technically more challenging than photon correlation measurements, which can be made insensitive to many of these imperfections. Ubiquitous in the characterization of Gaussian continuous-variable quantum memories [10][11][12][13][14], this technique has been extended during the past decade to analyze non-Gaussian states produced with heralded parametric or hot atomic vapor light sources [9,15], and very recently with an optical quantum memory [16]. Transposing it to a cold atomic ensemble, where quantum light states can not only be stored but also processed, should form an ideal system for studying nonlinear transformations of few-photon states due to atomic interactions.…”

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confidence: 99%

Pure Photons for Quantum Communications

Schleier-Smith¹,

Tanji-Suzuki²

2014

Physics

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We experimentally demonstrate that a nonclassical state prepared in an atomic memory can be efficiently transferred to a single mode of free-propagating light. By retrieving on demand a single excitation from a cold atomic gas, we realize an efficient source of single photons prepared in a pure, fully controlled quantum state. We characterize this source using two detection methods, one based on photon-counting analysis and the second using homodyne tomography to reconstruct the density matrix and Wigner function of the state. The latter technique allows us to completely determine the mode of the retrieved photon in its fine phase and amplitude details and demonstrate its nonclassical field statistics by observing a negative Wigner function. We measure a photon retrieval efficiency up to 82% and an atomic memory coherence time of 900 ns. This setup is very well suited to study interactions between atomic excitations and use them in order to create and manipulate more sophisticated quantum states of light with a high degree of experimental control. Precisely controlling quantum states of light is crucial for many quantum information processing (QIP) tasks. In this respect, cold atomic ensembles are a very versatile tool. In the past decade, they have been extensively used to store and retrieve quantum states of light [1] and, more recently, to manipulate them using atomic interactions [2][3][4]. Quite often, however, the resulting quantum states were characterized only partially, typically by photon correlation measurements insensitive to the exact frequency or temporal envelope of the emitted photons. Although independent atomic ensembles have been shown to emit photons with a good degree of indistinguishability [5][6][7][8], their exact wave functions remained to be characterized. Demonstrating that strongly nonclassical states stored in an atomic ensemble can be retrieved on demand as single-mode, Fouriertransform limited light pulses is an important requirement to use such systems in QIP and to connect them to other QIP devices.A very convenient way to fully characterize the retrieved quantum state is to use homodyne tomography [9], by reconstructing the photons' density matrix and Wigner function from the quadrature distributions of the light field measured by interference with a bright local oscillator. Since this technique characterizes the light's field rather than its intensity, it is intrinsically single mode and very sensitive to optical losses. Therefore, observing nonclassical features in the reconstructed quantum state proves that it can truly be emitted on demand, detected with a high efficiency, and controlled in all of its degrees of freedom which must exactly match those of the local oscillator. For a nonclassical state, the field's quadrature statistics are described by a non-Gaussian Wigner function taking negative values: losses or imperfections in the spatial mode, the polarization, the temporal envelope, or the frequency of the state will degrade the signal and eventually make its Wigner fu...

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Quantum Memory for Squeezed Light

Cited by 369 publications

References 32 publications

Dynamical Gaussian state transfer with quantum-error-correcting architecture

Dynamical Gaussian state transfer with quantum-error-correcting architecture

High-speed spatially multimode atomic memory

Pure Photons for Quantum Communications

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