Quantum states are essential resource for quantum-enhanced applications.Loss incurred in the distribution channel,however,dissipates the high signal-to-noise ratio advantage enjoyed by the squeezed state.Here,we first...Quantum states are essential resource for quantum-enhanced applications.Loss incurred in the distribution channel,however,dissipates the high signal-to-noise ratio advantage enjoyed by the squeezed state.Here,we first demonstrate noise immunity enhancement by using phase-sensitive amplifier(PSA)with measurement-based noiseless linear amplifier(MB-NLA).We explore the signal transfer capability with the amplifier in a noisy channel.The MB-NLA enhanced PSA has obvious suppression effect on channel noises,especially it has improvement for the noise contaminated signal.Better performance can be achieved by flexibly adjusting amplifier parameters.With the amplifier,it is promising to overcome the entanglement-distribution loss and show its superiority in squeezing based quantum sensing.展开更多
Single-photon entanglement(SPE) is an important source in quantum communication. In this paper, we put forward a single-photon-assisted noiseless linear amplification protocol to protect the SPE of an arbitrary polari...Single-photon entanglement(SPE) is an important source in quantum communication. In this paper, we put forward a single-photon-assisted noiseless linear amplification protocol to protect the SPE of an arbitrary polarization–time-bin qudit from the photon transmission loss caused by the practical channel noise. After the amplification, the fidelity of the SPE can be effectively increased. Meanwhile, the encoded polarization–time-bin features of the qudit can be well preserved. The protocol can be realized under the current experimental conditions. Moreover, the amplification protocol can be extended to resist complete photon loss and partial photon loss during the photon transmission. After the amplification, we can not only increase the fidelity of the target state, but also solve the decoherence problem simultaneously. Based on the above features, our amplification protocol may be useful in future quantum communication.展开更多
1 Statement of Limit Theorems Let A={a<sub>1</sub>,…, a<sub>|A|</sub>} be a finite alphabet, B={0, 1}, and N={0, 1,…}. By A<sup>n</sup>（A<sup>∞</sup>, resp.）, we de...1 Statement of Limit Theorems Let A={a<sub>1</sub>,…, a<sub>|A|</sub>} be a finite alphabet, B={0, 1}, and N={0, 1,…}. By A<sup>n</sup>（A<sup>∞</sup>, resp.）, we denote the set of words with the length n（∞, resp.） from the alphabet A; let A<sup>*</sup>= A<sup>n</sup>. B<sup>n</sup>, B<sup>∞</sup> and B<sup>*</sup> are defined similarly. A<sup>n</sup>（A<sup>∞</sup>, resp.） is also considered to be the n-fold （infinite, resp.） Cartesian product of A. If x=（x<sub>i</sub>） is a finite or infinite展开更多
Quantum illumination, that is, quantum target detection, is to detect the potential target with two-mode quan- tum entangled state. For a given transmitted energy, the quantum illumination can achieve a target-detecti...Quantum illumination, that is, quantum target detection, is to detect the potential target with two-mode quan- tum entangled state. For a given transmitted energy, the quantum illumination can achieve a target-detection probability of error much lower than the illumination scheme without entanglement. We investigate the useful- ness of noiseless linear amplification （NLA） for quantum illumination. Our result shows that NLA can help to substantially reduce the number of quantum entangled states collected for joint measurement of multi-copy quan- tum state. Our analysis on the NLA-assisted scheme could help to develop more efficient schemes for quantum illumination.展开更多
Noiseless linear amplification （NLA）, first proposed by Ralpha et al., is a nondeterministic amplification process which gives gain to the Fock state ｜n） → gn｜n）, with g being the amplification gain. We here gi...Noiseless linear amplification （NLA）, first proposed by Ralpha et al., is a nondeterministic amplification process which gives gain to the Fock state ｜n） → gn｜n）, with g being the amplification gain. We here give a general frame- work for improving the NLA scheme with arbitrary general local unitary operations. We derive the improvement in the amplification gain in 0 1 photon subspace. In particular, we study if the local unitary is composed of sin- gle mode squeezing and coherent displacement operation. Finally, numerical simulations show that local unitary operation could give a further enhancement in the amplification gain as well as the success probability, making the NLA more feasible in future optic quantum communications.展开更多
基金the National Natural Science Foundation of China(Grant No.12074233)the National Key Research and Development Program of China(Grant No.2021YFC2201802)Shanxi(1331 Project)。
文摘Quantum states are essential resource for quantum-enhanced applications.Loss incurred in the distribution channel,however,dissipates the high signal-to-noise ratio advantage enjoyed by the squeezed state.Here,we first demonstrate noise immunity enhancement by using phase-sensitive amplifier(PSA)with measurement-based noiseless linear amplifier(MB-NLA).We explore the signal transfer capability with the amplifier in a noisy channel.The MB-NLA enhanced PSA has obvious suppression effect on channel noises,especially it has improvement for the noise contaminated signal.Better performance can be achieved by flexibly adjusting amplifier parameters.With the amplifier,it is promising to overcome the entanglement-distribution loss and show its superiority in squeezing based quantum sensing.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474168 and 11747161)the Priority Academic Program Development of Jiangsu Higher Education Institutions,Chinathe China Postdoctoral Science Foundation(Grant No.2018M642293)
文摘Single-photon entanglement(SPE) is an important source in quantum communication. In this paper, we put forward a single-photon-assisted noiseless linear amplification protocol to protect the SPE of an arbitrary polarization–time-bin qudit from the photon transmission loss caused by the practical channel noise. After the amplification, the fidelity of the SPE can be effectively increased. Meanwhile, the encoded polarization–time-bin features of the qudit can be well preserved. The protocol can be realized under the current experimental conditions. Moreover, the amplification protocol can be extended to resist complete photon loss and partial photon loss during the photon transmission. After the amplification, we can not only increase the fidelity of the target state, but also solve the decoherence problem simultaneously. Based on the above features, our amplification protocol may be useful in future quantum communication.
文摘1 Statement of Limit Theorems Let A={a<sub>1</sub>,…, a<sub>|A|</sub>} be a finite alphabet, B={0, 1}, and N={0, 1,…}. By A<sup>n</sup>（A<sup>∞</sup>, resp.）, we denote the set of words with the length n（∞, resp.） from the alphabet A; let A<sup>*</sup>= A<sup>n</sup>. B<sup>n</sup>, B<sup>∞</sup> and B<sup>*</sup> are defined similarly. A<sup>n</sup>（A<sup>∞</sup>, resp.） is also considered to be the n-fold （infinite, resp.） Cartesian product of A. If x=（x<sub>i</sub>） is a finite or infinite
基金Supported by the National Natural Science Foundation of China under Grant Nos U1304613,11204197,11204379 and 11074244the National Basic Research Program of China under Grant No 2011CBA00200the Doctor Science Research Foundation from the Ministry of Education of China under Grant No 20113402110059
文摘Quantum illumination, that is, quantum target detection, is to detect the potential target with two-mode quan- tum entangled state. For a given transmitted energy, the quantum illumination can achieve a target-detection probability of error much lower than the illumination scheme without entanglement. We investigate the useful- ness of noiseless linear amplification （NLA） for quantum illumination. Our result shows that NLA can help to substantially reduce the number of quantum entangled states collected for joint measurement of multi-copy quan- tum state. Our analysis on the NLA-assisted scheme could help to develop more efficient schemes for quantum illumination.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11304013,11204197,11204379 and 11074244the National Basic Research Program of China under Grant No 2011CBA00200+1 种基金the Doctor Science Research Foundation of Ministry of Education of China under Grant No 20113402110059Civil Aerospace 2013669
文摘Noiseless linear amplification （NLA）, first proposed by Ralpha et al., is a nondeterministic amplification process which gives gain to the Fock state ｜n） → gn｜n）, with g being the amplification gain. We here give a general frame- work for improving the NLA scheme with arbitrary general local unitary operations. We derive the improvement in the amplification gain in 0 1 photon subspace. In particular, we study if the local unitary is composed of sin- gle mode squeezing and coherent displacement operation. Finally, numerical simulations show that local unitary operation could give a further enhancement in the amplification gain as well as the success probability, making the NLA more feasible in future optic quantum communications.
