Supporting long distance entanglement distribution with room temperature quantum repeaters

2021 ◽  
Author(s):  
Noel Goddard
Keyword(s):  
Room Temperature ◽  
Long Distance ◽  
Entanglement Distribution ◽  
Quantum Repeaters

scholarly journals Quantum repeaters based on concatenated bosonic and discrete-variable quantum codes

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Filip Rozpędek ◽  
Kyungjoo Noh ◽  
Qian Xu ◽  
Saikat Guha ◽  
Liang Jiang
Keyword(s):  
Continuous Variable ◽  
Quantum Codes ◽  
Discrete Variable ◽  
Long Distance ◽  
Concatenated Code ◽  
Different Types ◽  
Optical Modes ◽  
Distance Communication ◽  
Quantum Repeaters ◽  
Quantum Error

AbstractWe propose an architecture of quantum-error-correction-based quantum repeaters that combines techniques used in discrete- and continuous-variable quantum information. Specifically, we propose to encode the transmitted qubits in a concatenated code consisting of two levels. On the first level we use a continuous-variable GKP code encoding the qubit in a single bosonic mode. On the second level we use a small discrete-variable code. Such an architecture has two important features. Firstly, errors on each of the two levels are corrected in repeaters of two different types. This enables for achieving performance needed in practical scenarios with a reduced cost with respect to an architecture for which all repeaters are the same. Secondly, the use of continuous-variable GKP code on the lower level generates additional analog information which enhances the error-correcting capabilities of the second-level code such that long-distance communication becomes possible with encodings consisting of only four or seven optical modes.

Teleportation of a controlled-NOT gate for photon and electron-spin qubits assisted by the nitrogen-vacancy center

2015 ◽  
Vol 15 (15&16) ◽  
pp. 1397-1419
Author(s):  
Ming-Xing Luo ◽  
Hui-Ran Li
Keyword(s):  
Electron Spin ◽  
Spin System ◽  
Room Temperature ◽  
Coherence Time ◽  
Nitrogen Vacancy ◽  
Cnot Gate ◽  
Long Distance ◽  
Two Photon ◽  
Nitrogen Vacancy Center ◽  
Vacancy Center

Teleportations of quantum gates are very important in the construction of quantum network and teleportation-based model of quantum computation. Assisted with nitrogenvacancy centers, we propose several schemes to teleport the quantum CNOT gate. Deterministic CNOT gate may be implemented on a remote two-photon system, remote two electron-spin system, hybrid photon-spin system or hybrid spin-photon system. Each photon only interacts with one spin each time. Moreover, quantum channel may be constructed by all combinations of the photon or electron-spin entanglement, or their hybrid entanglement. Since these electron-spin systems have experimentally shown a long coherence time even at the room temperature, our schemes provide useful ways for long-distance quantum applications.

Continuous Variable Entanglement Distribution for Long-Distance Quantum Communication

2013 ◽  
Vol 30 (6) ◽  
pp. 060302 ◽  
Author(s):  
Jun-Jun Zhao ◽  
Xiao-Min Guo ◽  
Xu-Yang Wang ◽  
Ning Wang ◽  
Yong-Min Li ◽  
...  
Keyword(s):  
Quantum Communication ◽  
Continuous Variable ◽  
Long Distance ◽  
Entanglement Distribution

Evidence for Long-range Hydrogen Motion in a-Si:H under Room-temperature Illumination Using Raman Scattering of Amorphous Tungsten Oxide Overlayer

2001 ◽  
Vol 664 ◽  
Author(s):  
Hyeonsik M. Cheong ◽  
Se-Hee Lee ◽  
Brent Nelson ◽  
Angelo Mascarenhas ◽  
Sayten K. Deb
Keyword(s):  
Raman Spectrum ◽  
Tungsten Oxide ◽  
Long Range ◽  
Room Temperature ◽  
Hydrogen Diffusion ◽  
High Sensitivity ◽  
Raman Signal ◽  
Hydrogen Atoms ◽  
Long Distance ◽  
Staebler Wronski Effect

ABSTRACTWe demonstrate that one can detect minuscule amounts of hydrogen diffusion out of a-Si:H under illumination at room temperature, by monitoring the changes in the Raman spectrum of amorphous tungsten oxide as a function of illumination. The Staebler-Wronski effect, the light-induce creation of metastable defects in hydrogenated amorphous silicon (a-Si:H), has been one of the major problems that has limited the performance of such devices as solar cells. Recently, Branz suggested the hydrogen collision model that can explain many aspects of the Staebler-Wronski effect. One of the main predictions of this model is that the photogenerated mobile hydrogen atoms can move a long distance at room temperature. However, light-induced hydrogen motion in a-Si:H has not been experimentally observed at room temperature. We utilized the high sensitivity of the Raman spectrum of electrochromic a-WO3 to hydrogen insertion to probe the long-range motion of hydrogen at room temperature. We deposited a thin (200 nm) layer of a-WO3 on top of a-Si:H, and under illumination, a change in the Raman spectrum was detected. By comparing the Raman signal changes with those for control experiments where hydrogen is electrochemically inserted into a-WO3, we can estimate semiquantitatively the amount of hydrogen that diffuses out of the a-Si:H layer.

scholarly journals Parameter regimes for surpassing the PLOB bound with error-corrected qudit repeaters

Quantum ◽  
2019 ◽  
Vol 3 ◽  
pp. 216 ◽  
Author(s):  
Daniel Miller ◽  
Timo Holz ◽  
Hermann Kampermann ◽  
Dagmar Bruß
Keyword(s):  
Secure Communication ◽  
Quantum Communication ◽  
Quantum Repeater ◽  
Long Distance ◽  
Quantum Networks ◽  
Quantum Capacity ◽  
Higher Dimensional ◽  
Quantum Repeaters ◽  
New Applications ◽  
Provably Secure

A potential quantum internet would open up the possibility of realizing numerous new applications, including provably secure communication. Since losses of photons limit long-distance, direct quantum communication and wide-spread quantum networks, quantum repeaters are needed. The so-called PLOB-repeaterless bound [Pirandola et al., Nat. Commun. 8, 15043 (2017)] is a fundamental limit on the quantum capacity of direct quantum communication. Here, we analytically derive the quantum-repeater gain for error-corrected, one-way quantum repeaters based on higher-dimensional qudits for two different physical encodings: Fock and multimode qudits. We identify parameter regimes in which such quantum repeaters can surpass the PLOB-repeaterless bound and systematically analyze how typical parameters manifest themselves in the quantum-repeater gain. This benchmarking provides a guideline for the implementation of error-corrected qudit repeaters.

scholarly journals A hybrid quantum memory–enabled network at room temperature

2020 ◽  
Vol 6 (6) ◽  
pp. eaax1425
Author(s):  
Xiao-Ling Pang ◽  
Ai-Lin Yang ◽  
Jian-Peng Dou ◽  
Hang Li ◽  
Chao-Ni Zhang ◽  
...  
Keyword(s):  
High Speed ◽  
Information Technologies ◽  
Room Temperature ◽  
Schwarz Inequality ◽  
Quantum Memory ◽  
Atomic Ensemble ◽  
Single Photons ◽  
Long Distance ◽  
Atomic Excitations ◽  
A Chain

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 different from those envisioned for local processing. 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. Interfacing the quantum memories at room temperature, we observe a well-preserved quantum correlation and a violation of Cauchy-Schwarz inequality. 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.

Experimental Investigation on Stochastic Crack Growth Model of GH4133B at Fatigue-Creep

2009 ◽  
Author(s):  
Dianyin Hu ◽  
Rongqiao Wang
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Crack Growth ◽  
Room Temperature ◽  
Deterministic Model ◽  
Hold Time ◽  
Testing Machine ◽  
Crack Size ◽  
Long Distance ◽  
Crack Growth Model

Experiments on the fatigue crack growth have shown great dispersancy. Study on stochastic crack growth of material at room temperature has been widely performed. However, probabilistic model for crack growth at fatigue-creep has been little investigated due to the complexity of the deterministic model for crack growth at fatigue-creep as well as the time-consuming and the difficulty of the experiments. Traditional crack measurement such as direct current and alternating current electrical potential technique, compliance method is limited for circuit interference at large crack, especially when the temperature is higher than 500°C. Experimental system to achieve real-time FCCG detection at high temperature is established by introducing a long-distance microscope with high magnification and resolution from distances of 15cm to 35cm. The experimental setup consists of a dynamic testing machine, a machine controller, a temperature controlled box, a long-distance microscope and a high temperature furnace from room temperature to 1000°C. Then the fatigue-creep crack growth (FCCG) rate tests on thirty compact tension (CT) specimens made of GH4133B material at 600°C are carried out. The reason for choosing the GH4133B Ni-based superalloy is owing to its popularity in use for the turbine disc of the aero-engine. The tests are conducted on a 100KN capacity servo-hydraulic closed-loop machine employed trapezoidal load with hold time at upon peak load. Based on the crack growth models used for room temperature, the deterministic model for FCCG rate considering the parameters including temperature, hold time is established through comparison of the analytical results with the experimental data. Then the stochastic FCCG model for GH4133B is proposed and the probability of random to reach a specified crack size can be obtained as well as the distribution function of crack size at the service time. Through comparison between the analytical and experimental results, it’s found that the probabilistic FCCG model can fit the experimental data well. Once the stochastic FCCG model is established, it can be used for the probabilistic damage tolerance design of the turbine components made of GH4133B material.

Long-distance quantum teleportation assisted with free-space entanglement distribution

2009 ◽  
Vol 18 (8) ◽  
pp. 3605-3610 ◽  
Author(s):  
Ren Ji-Gang ◽  
Yang Bin ◽  
Yi Zhen-Huan ◽  
Zhou Fei ◽  
Chen Kai ◽  
...  
Keyword(s):  
Free Space ◽  
Quantum Teleportation ◽  
Long Distance ◽  
Entanglement Distribution
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