A broadband DLCZ quantum memory in room-temperature atoms

Dou, Jian-Peng; Yang, Ai-Lin; Du, Mu-Yan; Lao, Di; Gao, Jun; Qiao, Lu-Feng; Li, Hang; Pang, Xiao-Ling; Feng, Zhen; Tang, Hao; Jin, Xian

doi:10.1038/s42005-018-0057-9

Cited by 48 publications

(41 citation statements)

References 42 publications

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“…The bandwidths of the signal and idler photons are 590 MHz and 641 MHz respectively, which confirms the broadband property of the correlated photons that are determined by the pulse duration of the coupling light (2 ns). This observed broadband nonclassical state, associated with a well-defined creation time, is therefore well compatible with Raman [16] and FORD [19] broadband quantum memory for future quantum enhanced applications.…”

Section: Resultssupporting

confidence: 66%

“…The far off-resonance and Λ-type configuration shown in Fig. 1(a) are the two main features that our scheme shares with Raman [16] and FORD [19] broadband quantum memory. The two lower states |1 6S 1/2 , F = 3 and |3 6S 1/2 , F = 4 are the hyperfine ground states of 133 Cs with a frequency difference of 9.19 GHz, and the upper state |2 is the excited state that we mark at the cross over between 6P 3/2 , F = 4 and F = 5 as a precise reference.…”

Section: Resultsmentioning

confidence: 69%

“…With this we achieve the direct observation of broadband nonclasscal states in a room-temperature light-matter interface, where the atoms can also be controlled to store and interfere with photons. The obtained nonclassical states are compatible and therefore can be directly used to interfere with broadband offresonance quantum memories [16,19].…”

Section: Discussionmentioning

confidence: 85%

“…Albeit there are advances of pushing bandwidth from narrowband to broadband and storage media from ultra-cold atomic gas to room-temperature atomic vapour [7][8][9][10][11][12][13][14][15][16][17], it is not until recently that the room-temperature broadband memories being capable of operating with a high fidelity genuinely in quantum regime were achieved [18,19]. However, the spectrum of conventional optical down conversion by pumping a nonlinear crystal is still too large to match the acceptance bandwidth of quantum memories.…”

Section: Introductionmentioning

confidence: 99%

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Direct observation of broadband nonclassical states in a room-temperature light–matter interface

Dou¹,

Yang²,

Du³

et al. 2018

npj Quantum Inf

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Nonclassical state is an essential resource for quantumenhanced communication, computing and metrology to outperform their classical counterpart. The nonclassical states that can operate at high bandwidth and room temperature while being compatible with quantum memory are highly desirable to enable the scalability of quantum technologies. Here, we present a direct observation of broadband nonclasscal states in a room-temperature lightmatter interface, where the atoms can also be controlled to store and interfere with photons. With a single coupling pulse and far off-resonance configuration, we are able to induce a multi-field interference between light and atoms to create the desired nonclassical states by spectrally selecting the two correlated photons out of seven possible emissions. We explicitly confirm the nonclassicality by observing a cross correlation up to 17 and a violation of Cauchy-Schwarz inequality with 568 standard deviations. Our results demonstrate the potential of a state-built-in, broadband and room-temperature light-matter interface for scalable quantum information networks.

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Section: Resultssupporting

confidence: 66%

Section: Resultsmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Direct observation of broadband nonclassical states in a room-temperature light–matter interface

Dou¹,

Yang²,

Du³

et al. 2018

npj Quantum Inf

Self Cite

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“…According to the convolution-based approach (Ref. 31), scanning the detuning of write/read pulses, we record the distributions of Stokes and anti-Stokes photons, as shown in Figure 6(b). And eventually, the spectra of Stokes and anti-Stoke photons can be calculated by utilizing convolution theorem and Fourier transform.…”

Section: Improved Bandwidth-match Between Signal Photons and Cavimentioning

confidence: 99%

A hybrid quantum memory–enabled network at room temperature

et al. 2020

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Teaser: Building quantum network with roomtemperature atomic and all-optical memories for scalable quantum information processing.Quantum memory capable of storage and retrieval of flying photons on demand is crucial for developing quantum information technologies. However, the devices needed for long-distance links are quite different from those envisioned for local processing. Here, we present the first hybrid quantum memory enabled network by demonstrating the interconnection and simultaneous operation of two types of quantum memory: an atomic-ensemble-based memory and an all-optical loop memory. The former generates and stores single atomic excitations that can then be converted to single photons; and the latter maps incoming photons in and out on demand, at room-temperature and with a broad acceptance bandwidth. Interfacing these two types of quantum memories, we observe a well-preserved quantum cross-correlation, reaching a value of 22, and a violation of the Cauchy-Schwarz inequality up to 549 standard deviations. Furthermore, we demonstrate the creation and storage of a fully operable heralded photon chain state that can achieve memory-built-in combining, swapping, splitting, tuning and chopping single photons in a chain temporally. Such a quantum network allows atomic excitations to be generated, stored, and converted to broadband photons, which are then transferred to the next node, stored, and faithfully retrieved, all at high speed and in a programmable fashion.

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Room‐Temperature Quantum Memories Based on Molecular Electron Spin Ensembles

et al. 2021

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Superconducting quantum bits are addressed by means of microwave radiation and quantum memories in this context thus need to be able to store microwave photon states. To this end, resonant structures for electromagnetic radiation can be used to strongly couple quantum bits and quantum memories to quantized cavity modes of the electromagnetic field. The strong coupling generates a hybrid quantum system that allows mapping the qubit state onto the cavity field state. [6] This strategy has given rise to the field of cavity quantum electrodynamics and has already been used to couple two superconducting qubits together via a cavity bus. [7] A second application of quantum memories is in quantum repeaters for quantum communication. Because telecom wavelengths are in the near-infrared, for this application, optical quantum memories are required that store optical photon states. [8] Considering the choice of material platform for designing microwave quantum memories, electron spins in solids can be easily addressed by microwave pulses and have been shown to possess excellent coherence times up to seconds, for some systems even up to room temperature. [9][10] Unfortunately, the coupling of a single electron spin to a photon is very weak. Although resonant structures can be tailored to improve single-spin coupling, [11][12][13] the weakness of the coupling renders addressing individual spins by means of coupling to cavity modes very challenging. This can be overcome by using an electron spin ensemble rather than single spins, because the coupling strength of a spin ensemble to an electromagnetic resonator mode is proportional to the square root of the number of electron spins in the ensemble. [14] This then leads to the general idea of the implementation of a microwave quantum memory using spin ensembles and microwave resonators (Figure 1). The state to be stored is encoded in a weak microwave pulse and sent to the hybrid quantum system constituted of an electron spin ensemble that is strongly coupled to a microwave resonator, where it is stored. When the quantum state is needed again, a strong microwave pulse is sent to the resonator, which leads to deterministic retrieval of the quantum state that is emitted as a microwave photon to be used as desired.Strong coupling between cavity and electron spin ensembles has been observed in a variety of spin systems, including organic radicals, [15][16][17][18][19][20] phosphorous dopants in silicon, [21,22] P1 and nitrogen vacancy (NV) defects in diamond, [23][24][25][26][27][28][29][30][31][32] N@ C 60 , [33] rare earth dopants in oxides, [34,35] transition metal Whilst quantum computing has recently taken great leaps ahead, the development of quantum memories has decidedly lagged behind. Quantum memories are essential devices in the quantum technology palette and are needed for intermediate storage of quantum bit states and as quantum repeaters in long-distance quantum communication. Current quantum memories operate at cryogenic, mostly sub-Kelvin temperatures and require extens...

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A broadband DLCZ quantum memory in room-temperature atoms

Cited by 48 publications

References 42 publications

Direct observation of broadband nonclassical states in a room-temperature light–matter interface

Direct observation of broadband nonclassical states in a room-temperature light–matter interface

A hybrid quantum memory–enabled network at room temperature

Room‐Temperature Quantum Memories Based on Molecular Electron Spin Ensembles

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