scholarly journals Distributed construction of quantum fingerprints

2004 ◽  
Vol 4 (2) ◽  
pp. 146-151
Author(s):  
A. Ambainis ◽  
Y-Y Shi
Keyword(s):  
Quantum Communication ◽  
Communication Protocol ◽  
Physical Review ◽  
Communication Problem ◽  
Classical Protocol ◽  
Quantum Communication Protocol

Quantum fingerprints are useful quantum encodings introduced by Buhrman, Cleve, Watrous and de Wolf (Physical Review Letters, Volume 87, Number 16, Article 167902, 2001) to obtain an efficient quantum communication protocol. We design a protocol for constructing the fingerprint in a distributed scenario. As an application, this protocol gives rise to a communication protocol more efficient than the best known classical protocol for a communication problem.

scholarly journals Efficient quantum communication under collective noise

2013 ◽  
Vol 13 (3&4) ◽  
pp. 290-323
Author(s):  
Michael Skotiniotis ◽  
Wolfgang Dur ◽  
Barbara Kraus
Keyword(s):  
Quantum Information ◽  
Discrete Group ◽  
Quantum Communication ◽  
Communication Protocol ◽  
Transmission Rate ◽  
Collective Noise ◽  
Cyclic Groups ◽  
Time Encoding ◽  
Decoherence Free Subspace ◽  
Quantum Communication Protocol

We introduce a new quantum communication protocol for the transmission of quantum information under collective noise. Our protocol utilizes a decoherence-free subspace in such a way that an optimal asymptotic transmission rate is achieved, while at the same time encoding and decoding operations can be efficiently implemented. The encoding and decoding circuit requires a number of elementary gates that scale linearly with the number of transmitted qudits, $m$. The logical depth of our encoding and decoding operations is constant and depends only on the channel in question. For channels described by an arbitrary discrete group $G$, i.e.~with a discrete number, $\lvert G\rvert$, of possible noise operators, perfect transmission at a rate $m/(m+r)$ is achieved with an overhead that scales at most as $\mathcal{O}(d^r)$ where the number of auxiliary qudits, $r$, depends solely on the group in question. Moreover, this overhead is independent of the number of transmitted qudits, $m$. For certain groups, e.g.~cyclic groups, we find that the overhead scales only linearly with the number of group elements $|G|$.

Multi-party qutrit-state sharing under decoherence

2020 ◽  
Vol 34 (12) ◽  
pp. 2050124
Author(s):  
Zhiming Huang ◽  
Zhimin He
Keyword(s):  
Quantum System ◽  
Quantum State ◽  
Quantum Coherence ◽  
Quantum Communication ◽  
Communication Protocol ◽  
Entangled State ◽  
Quantum State Sharing ◽  
Noisy Environment ◽  
Realistic Situation ◽  
Quantum Communication Protocol

Quantum state sharing plays an important role in both transmitting and protecting a quantum secret information. However, in a realistic situation, quantum communication protocol is inevitably affected by the decoherence and noise induced by the interaction between quantum system and environment, which often destroys quantum resource, such as degrading entangled state that is often used as the key resource of quantum communication. In this paper, we intend to investigate the influence of amplitude damping (AD) decoherence on multi-party qutrit-state sharing (MQSS) scheme. We firstly construct the noisy model of MQSS, and then analyze the effect of decoherence on the MQSS. In addition, the relation of variations between MQSS performance and quantum coherence is illustrated. Furthermore, we propose a partial measurement to enhance the performance of the MQSS under noisy environment.

scholarly journals High-fidelity spatial mode transmission through a 1-km-long multimode fiber via vectorial time reversal

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yiyu Zhou ◽  
Boris Braverman ◽  
Alexander Fyffe ◽  
Runzhou Zhang ◽  
Jiapeng Zhao ◽  
...  
Keyword(s):  
Time Reversal ◽  
Quantum Communication ◽  
Communication Protocol ◽  
Signal Beam ◽  
High Fidelity ◽  
Spatial Mode ◽  
Multimode Fibers ◽  
Spatial Modes ◽  
Potential Applications ◽  
Quantum Communication Protocol

AbstractThe large number of spatial modes supported by standard multimode fibers is a promising platform for boosting the channel capacity of quantum and classical communications by orders of magnitude. However, the practical use of long multimode fibers is severely hampered by modal crosstalk and polarization mixing. To overcome these challenges, we develop and experimentally demonstrate a vectorial time reversal technique, which is accomplished by digitally pre-shaping the wavefront and polarization of the forward-propagating signal beam to be the phase conjugate of an auxiliary, backward-propagating probe beam. Here, we report an average modal fidelity above 80% for 210 Laguerre-Gauss and Hermite-Gauss modes by using vectorial time reversal over an unstabilized 1-km-long fiber. We also propose a practical and scalable spatial-mode-multiplexed quantum communication protocol over long multimode fibers to illustrate potential applications that can be enabled by our technique.

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