Quantum memory
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Highly efficient optical quantum memory with long coherence time in cold atoms Open
Optical quantum memory is an essential element for long distance quantum communication and photonic quantum computation protocols. The practical implementation of such protocols requires an efficient quantum memory with long coherence time…
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Hardware-Efficient Quantum Random Access Memory with Hybrid Quantum Acoustic Systems Open
Hybrid quantum systems in which acoustic resonators couple to superconducting qubits are promising quantum information platforms. High quality factors and small mode volumes make acoustic modes ideal quantum memories, while the qubit-phono…
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Tightening the entropic uncertainty bound in the presence of quantum memory Open
The uncertainty principle is a fundamental principle in quantum physics. It\nimplies that the measurement outcomes of two incompatible observables can not\nbe predicted simultaneously. In quantum information theory, this principle can\nbe …
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Towards highly multimode optical quantum memory for quantum repeaters Open
Long-distance quantum communication through optical fibers is currently limited to a few hundreds of kilometres due to fiber losses. Quantum repeaters could extend this limit to continental distances. Most approaches to quantum repeaters r…
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Optical quantum memory based on electromagnetically induced transparency Open
Electromagnetically induced transparency (EIT) is a promising approach to implement quantum memory in quantum communication and quantum computing applications. In this paper, following a brief overview of the main approaches to quantum mem…
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Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons Open
Quantum memories matched to single photon sources will form an important cornerstone of future quantum network technology. We demonstrate such a memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically ind…
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A quantum spectrum analyzer enhanced by a nuclear spin memory Open
We realize a two-qubit sensor designed for achieving high-spectral resolution in quantum sensing experiments. Our sensor consists of an active “sensing qubit” and a long-lived “memory qubit”, implemented by the electronic and the nitrogen-…
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Optical storage for 0.53 s in a solid-state atomic frequency comb memory using dynamical decoupling Open
Quantum memories with long storage times are key elements in long-distance quantum networks. The atomic frequency comb (AFC) memory in particular has shown great promise to fulfill this role, having demonstrated multimode capacity and spin…
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Using recurrent neural networks to optimize dynamical decoupling for quantum memory Open
We utilize machine learning models which are based on recurrent neural\nnetworks to optimize dynamical decoupling (DD) sequences. DD is a relatively\nsimple technique for suppressing the errors in quantum memory for certain noise\nmodels. …
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Memory-preserving equilibration after a quantum quench in a one-dimensional critical model Open
One of the fundamental principles of statistical physics is that only partial\ninformation about a system's state is required for its macroscopic description.\nThis is not only true for thermal ensembles, but also for the unconventional\ne…
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Generation of Light with Multimode Time-Delayed Entanglement Using Storage in a Solid-State Spin-Wave Quantum Memory Open
Here, we demonstrate generating and storing entanglement in a solid-state spin-wave quantum memory with on-demand readout using the process of rephased amplified spontaneous emission (RASE). Amplified spontaneous emission (ASE), resulting …
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Collective Quantum Memory Activated by a Driven Central Spin Open
Coupling a qubit coherently to an ensemble is the basis for collective quantum memories. A single driven electron in a quantum dot can deterministically excite low-energy collective modes of a nuclear spin ensemble in the presence of latti…
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A single-atom quantum memory in silicon Open
Long coherence times and fast gate operations are desirable but often conflicting requirements for physical qubits. This conflict can be resolved by resorting to fast qubits for operations, and by storing their state in a ‘quantum memory’ …
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Discerning quantum memories based on electromagnetically-induced-transparency and Autler-Townes-splitting protocols Open
Electromagnetically induced transparency (EIT) and Autler-Townes splitting (ATS) are similar,but different quantum optical phenomena: EIT results from a Fano interference, whereas ATS is described by the AC-Stark effect. Likewise, despite …
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Cavity-Enhanced Atom-Photon Entanglement with Subsecond Lifetime Open
A cold atomic ensemble suits well for optical quantum memories, and its entanglement with a single photon forms the building block for quantum networks that give promise for many revolutionary applications. Efficiency and lifetime are amon…
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Quantum predictions for an unmeasured system cannot be simulated with a finite-memory classical system Open
We consider an ideal experiment in which unlimited nonprojective quantum measurements are sequentially performed on a system that is initially entangled with a distant one. At each step of the sequence, the measurements are randomly chosen…
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Single-Photon-Memory Two-Step Quantum Secure Direct Communication Relying on Einstein-Podolsky-Rosen Pairs Open
Quantum secure direct communication (QSDC) is an important branch of quantum communication that is capable of directly transmitting secret messages over a quantum channel. It may be viewed as a concrete realization of Wyner’s wiretap chann…
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Measurement-device-independent quantum key distribution with nitrogen vacancy centers in diamond Open
Memory-assisted measurement-device-independent quantum key distribution (MA-MDI-QKD) has recently been proposed as a possible intermediate step towards the realization of quantum repeaters. Despite its relaxing some of the requirements on …
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Quantum Storage of Single-Photon and Two-Photon Fock States with an All-Optical Quantum Memory Open
Quantum memories are a crucial element toward efficient quantum protocols. In the continuous variables domain, such memories need to provide high fidelity with an efficiency set to one. Moreover, one needs to store complex quantum states e…
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Targeting molecular quantum memory with embedded error correction Open
The implementation of a quantum computer requires protecting of information from noise and the ability to perform quantum gates. We present a molecular architecture providing both these ingredients, via an electronic spin 1/2 processor and…
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Raman quantum memory with built-in suppression of four-wave-mixing noise Open
Quantum memories are essential for large-scale quantum information networks. Along with high efficiency, storage lifetime, and optical bandwidth, it is critical that the memory adds negligible noise to the recalled signal. A common source …
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Memory-assisted quantum key distribution with a single nitrogen-vacancy center Open
Memory-assisted measurement-device-independent quantum key distribution (MA-MDI-QKD) is a promising scheme that aims to improve the rate-versus-distance behavior of a QKD system by using the state-of-the-art devices. It can be seen as a br…
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Certification of high-dimensional entanglement and Einstein-Podolsky-Rosen steering with cold atomic quantum memory Open
The advent of structured, high-dimensional entangled states brings new\npossibilities for quantum imaging, information processing and quantum key\ndistribution. We experimentally generate and characterize a spatially entangled\nstate store…
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Black hole memory Open
The memory effect at null infinity, $\\mathcal{I}^+$, can be defined in terms\nof the permanent relative displacement of test particles (at leading order in\n$1/r$) resulting from the passage of a burst of gravitational radiation. In\n$D=4…
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Provably unbounded memory advantage in stochastic simulation using quantum mechanics Open
Simulating the stochastic evolution of real quantities on a digital computer requires a trade-off between the precision to which these quantities are approximated, and the memory required to store them. The statistical accuracy of the simu…
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Storage of polarization-entangled THz-bandwidth photons in a diamond quantum memory Open
Bulk diamond phonons have been shown to be a versatile platform for the generation, storage, and manipulation of high-bandwidth quantum states of light. Here we demonstrate a diamond quantum memory that stores, and releases on demand, an a…
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Improved uncertainty relation in the presence of quantum memory Open
In Coles-Piani's recent remarkable version of the entropic uncertainty\nprinciple, the entropic sum is controlled by the first and second maximum\noverlaps between the two projective measurements. We generalize the entropic\nuncertainty re…
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Broadband coherent optical memory based on electromagnetically induced transparency Open
Quantum memories, devices that can store and retrieve photonic quantum states on demand, are essential components for scalable quantum technologies. It is desirable to push the memory towards the broadband regime in order to increase the d…
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Multipartite uncertainty relation with quantum memory Open
We present a new quantum-memory-assisted entropic uncertainty relation for multipartite systems which shows the uncertainty principle of quantum mechanics. Notably, our results recover some well-known entropic uncertainty relations for two…
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Holographic Simulation of Correlated Electrons on a Trapped-Ion Quantum Processor Open
We develop holographic quantum simulation techniques to prepare correlated electronic ground states in quantum matrix-product-state (QMPS) form, using far fewer qubits than the number of orbitals represented. Our approach starts with a hol…