scholarly journals Verifying Quantum Communication Protocols with Ground Bisimulation

2020 ◽  
pp. 21-38
Author(s):  
Xudong Qin ◽  
Yuxin Deng ◽  
Wenjie Du
Keyword(s):  
Quantum Communication ◽  
Communication Protocols ◽  
Important Application ◽  
Process Algebras ◽  
Proof Technique ◽  
Quantum Processes ◽  
Quantum Process ◽  
Decision Method ◽  
Quantum Protocols ◽  
Suitable Notion

Abstract One important application of quantum process algebras is to formally verify quantum communication protocols. With a suitable notion of behavioural equivalence and a decision method, one can determine if an implementation of a protocol is consistent with its specification. Ground bisimulation is a convenient behavioural equivalence for quantum processes because of its associated coinduction proof technique. We exploit this technique to design and implement two on-the-fly algorithms for the strong and weak versions of ground bisimulation to check if two given processes in quantum CCS are equivalent. We then develop a tool that can verify interesting quantum protocols such as the BB84 quantum key distribution scheme.

Two semi-quantum secure direct communication protocols based on Bell states

2019 ◽  
Vol 34 (01) ◽  
pp. 1950004 ◽  
Author(s):  
Yuhua Sun ◽  
Lili Yan ◽  
Yan Chang ◽  
Shibin Zhang ◽  
Tingting Shao ◽  
...  
Keyword(s):  
Quantum Communication ◽  
Communication Protocols ◽  
Quantum Secure Direct Communication ◽  
Bell States ◽  
Secret Key ◽  
Direct Communication ◽  
Quantum Protocols ◽  
Shared Secret ◽  
Full Quantum ◽  
Qubit Efficiency

Quantum secure direct communication allows one participant to transmit secret messages to another directly without generating a shared secret key first. In most of the existing schemes, quantum secure direct communication can be achieved only when the two participants have full quantum ability. In this paper, we propose two semi-quantum secure direct communication protocols to allow restricted semi-quantum or “classical” users to participate in quantum communication. A semi-quantum user is restricted to measure, prepare, reorder and reflect quantum qubits only in the classical basis [Formula: see text]. Both protocols rely on quantum Alice to randomly prepare Bell states, perform Bell basis measurements and publish the initial Bell states, but the semi-quantum Bob only needs to measure the qubits in classical basis to obtain secret information without quantum memory. Security and qubit efficiency analysis have been given in this paper. The analysis results show that the two protocols can avoid some eavesdropping attacks and their qubit efficiency is higher than some current related quantum or semi-quantum protocols.

Superdense Coding and Quantum Teleportation

2006 ◽  
Author(s):  
Phillip Kaye ◽  
Raymond Laflamme ◽  
Michele Mosca
Keyword(s):  
Quantum Teleportation ◽  
Communication Channel ◽  
Quantum Communication ◽  
Communication Protocols ◽  
Bell State ◽  
Third Party ◽  
Classical Communication ◽  
Superdense Coding ◽  
Communication Task ◽  
Epr Pair

We are now ready to look at our first protocols for quantum information. In this section, we examine two communication protocols which can be implemented using the tools we have developed in the preceding sections. These protocols are known as superdense coding and quantum teleportation. Both are inherently quantum: there are no classical protocols which behave in the same way. Both involve two parties who wish to perform some communication task between them. In descriptions of such communication protocols (especially in cryptography), it is very common to name the two parties ‘Alice’ and ‘Bob’, for convenience. We will follow this tradition. We will repeatedly refer to communication channels. A quantum communication channel refers to a communication line (e.g. a fiberoptic cable), which can carry qubits between two remote locations. A classical communication channel is one which can carry classical bits (but not qubits).1 The protocols (like many in quantum communication) require that Alice and Bob initially share an entangled pair of qubits in the Bell state The above Bell state is sometimes referred to as an EPR pair. Such a state would have to be created ahead of time, when the qubits are in a lab together and can be made to interact in a way which will give rise to the entanglement between them. After the state is created, Alice and Bob each take one of the two qubits away with them. Alternatively, a third party could create the EPR pair and give one particle to Alice and the other to Bob. If they are careful not to let them interact with the environment, or any other quantum system, Alice and Bob’s joint state will remain entangled. This entanglement becomes a resource which Alice and Bob can use to achieve protocols such as the following. Suppose Alice wishes to send Bob two classical bits of information. Superdense coding is a way of achieving this task over a quantum channel, requiring only that Alice send one qubit to Bob. Alice and Bob must initially share the Bell state Suppose Alice is in possession of the first qubit and Bob the second qubit.

scholarly journals Characterization of depolarizing channels using two-photon interference

2019 ◽  
Vol 18 (11) ◽  
Author(s):  
G. C. Amaral ◽  
G. P. Temporão
Keyword(s):  
Quantum Communication ◽  
Communication Link ◽  
Time Varying ◽  
Quantum Process ◽  
Standard Quantum ◽  
Two Photon ◽  
Quantum Process Tomography ◽  
Process Tomography ◽  
Unitary Transformations

Abstract Depolarization is one of the most important sources of error in a quantum communication link that can be introduced by the quantum channel. Even though standard quantum process tomography can, in theory, be applied to characterize this effect, in most real-world implementations depolarization cannot be distinguished from time-varying unitary transformations, especially when the timescales are much shorter than the detectors response time. In this paper, we introduce a method for distinguishing true depolarization from fast polarization rotations by employing Hong–Ou–Mandel interference. It is shown that the results are independent of the timing resolutions of the photodetectors.

scholarly journals A model to estimate performance of space-based quantum communication protocols including quantum key distribution systems

2017 ◽  
Vol 16 (1) ◽  
pp. 5-13
Author(s):  
Jonathan C Denton ◽  
Douglas D Hodson ◽  
Richard G Cobb ◽  
Logan O Mailloux ◽  
Michael R Grimaila ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Distribution Systems ◽  
Quantum Communication ◽  
Channel Model ◽  
Communication Protocols ◽  
Key Distribution ◽  
General Purpose ◽  
Optical Channel ◽  
Use Case ◽  
Atmospheric Conditions

This work presents a model to estimate the performance of space-based, optical-based, quantum communication protocols. This model consists of components to account for optical channel propagation effects based on orbit selection and atmospheric conditions. The model presented is general purpose and can be leveraged to evaluate the performance of a variety of quantum communication protocols, of which, Quantum Key Distribution (QKD) systems served as our motivating use case of particular interest. To verify correctness, the model is used to produce estimates for QKD system scenarios and compared to published results. The performance of QKD systems is of interest as distance limitations for terrestrial-based systems have hindered their practical use, and satellite-based designs that can generate a shared key between two distant geographic locations have been proposed. For this application domain, a review of space-based designs that illuminate the need for a free space downlink channel model is presented followed by its development to estimate the performance of quantum exchanges between a satellite and ground site.

Superposition of causal orders for quantum discrimination of quantum processes

2019 ◽  
Vol 17 (07) ◽  
pp. 1950055
Author(s):  
Seid Koudia ◽  
Abdelhakim Gharbi
Keyword(s):  
Quantum Mechanics ◽  
Memory Effects ◽  
Causal Order ◽  
Quantum Processes ◽  
Quantum Process ◽  
Order Case ◽  
Ultimate Bound ◽  
Process Discrimination

We address the superposition of causal orders in the quantum switch as a convenient framework for quantum process discrimination in the presence of noise in qubit systems, using Bayes strategy. We show that, for different kinds of qubit noises, the indefinite causal order between the unitary to be discriminated and noise gives enhancement compared to the definite causal order case without reaching the ultimate bound of discrimination in general. Whereas, for entanglement breaking channels, the enhancement is significant, where the quantum switch allows for the attainability of the ultimate bound for discrimination posed by quantum mechanics. Memory effects escorting the superposition of causal orders are discussed, where we point out that processes describing an indefinite causal order, violate the notion of Markov locality. Accordingly, a suggestion for the simulation of indefinite causal orders in more generic scenarios beyond the quantum switch is given.

scholarly journals The security analysis of E91 protocol in collective-rotation noise channel

2018 ◽  
Vol 14 (5) ◽  
pp. 155014771877819 ◽  
Author(s):  
Leilei Li ◽  
Hengji Li ◽  
Chaoyang Li ◽  
Xiubo Chen ◽  
Yan Chang ◽  
...  
Keyword(s):  
Error Rate ◽  
Noise Level ◽  
Quantum Communication ◽  
Noise Analysis ◽  
Communication Protocols ◽  
Security Analysis ◽  
Noise Environment ◽  
Protocol Security ◽  
Collective Rotation ◽  
Collective Rotation Noise

The bit error in quantum communication is mainly caused by eavesdropping and noise. However, most quantum communication protocols only take eavesdropping into consideration and ignore the result of noise, making the inaccuracy situations in detecting the eavesdropper. To analyze the security of the quantum E91 protocol presented by Ekert in collective-rotation noise channel, an excellent model of noise analysis is proposed. The increment of the qubits error rate (ber) is used to detect eavesdropping. In our analysis, eavesdropper (Eve) can maximally get about 50% of the key from the communication when the noise level approximates to 0.5. The results show that in the collective-rotation noise environment, E91 protocol is secure and the raw key is available just as we have knew and proved. We also presented a new idea in analyzing the protocol security in noise channel.

scholarly journals Relations among quantum processes: bisimilarity and congruence

2006 ◽  
Vol 16 (3) ◽  
pp. 407-428 ◽  
Author(s):  
MARIE LALIRE
Keyword(s):  
Quantum Communication ◽  
Operational Semantics ◽  
Parallel Composition ◽  
Quantum Processes ◽  
Algebraic Notation ◽  
Distributed Computations ◽  
Quantum Objects ◽  
Branching Bisimulation ◽  
Classical Computing ◽  
Process Algebraic

Full formal descriptions of algorithms making use of quantum principles must take into account both quantum and classical computing components, as well as communications between these components. Moreover, to model concurrent and distributed quantum computations and quantum communication protocols, communications over quantum channels that move qubits physically from one place to another must also be taken into account.Inspired by classical process algebras, which provide a framework for modelling cooperating computations, a process algebraic notation is defined. This notation provides a homogeneous style for formal descriptions of concurrent and distributed computations comprising both quantum and classical parts. Based upon an operational semantics that makes sure that quantum objects, operations and communications operate according to the postulates of quantum mechanics, an equivalence is defined among process states considered as having the same behaviour. This equivalence is a probabilistic branching bisimulation. From this relation, an equivalence on processes is defined. However, it is not a congruence because it is not preserved by parallel composition.

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