Quantum communication protocols using the vacuum

2003 ◽  
Vol 3 (5) ◽  
pp. 423-430
Author(s):  
S.J. van Enk ◽  
T. Rudolph
Keyword(s):  
Quantum Information ◽  
Quantum Communication ◽  
Communication Protocols ◽  
Classical Information ◽  
Coin Flipping

We speculate what quantum information protocols can be implemented between two accelerating observers using the vacuum. Whether it is in principle possible or not to implement a protocol depends on whether the aim is to end up with classical information or quantum information. Thus, unconditionally secure coin flipping seems possible but not teleportation.

On the classical character of control fields in quantum information processing

2002 ◽  
Vol 2 (1) ◽  
pp. 1-13
Author(s):  
S.J. van Enk ◽  
H.J. Kimble
Keyword(s):  
Quantum Computing ◽  
Information Processing ◽  
Quantum Information ◽  
Laser Beam ◽  
Quantum State ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Laser Fields ◽  
Undesirable Property

Control fields in quantum information processing are almost by definition assumed to be classical. In reality, however, when such a field is used to manipulate the quantum state of qubits, the qubits always become slightly entangled with the field. For quantum information processing this is an undesirable property, as it precludes perfect quantum computing and quantum communication. Here we consider the interaction of atomic qubits with laser fields and quantify atom-field entanglement in various cases of interest. We find that the entanglement decreases with the average number of photons \bar{n} in a laser beam as $E\propto\log_2 \bar{n}/\bar{n}$ for $\bar{n}\rightarrow\infty$.

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.

Teleportation affected by fluctuating electromagnetic field with a boundary

2021 ◽  
Author(s):  
Zhiming Huang ◽  
Zhenbang Rong ◽  
Yiyong Ye
Keyword(s):  
Electromagnetic Field ◽  
Quantum Information ◽  
Quantum System ◽  
Quantum Teleportation ◽  
Quantum Communication ◽  
Open Quantum System ◽  
Plane Boundary ◽  
Atomic Polarization ◽  
Electromagnetic Fluctuation ◽  
Insight Into

We study the quantum teleportation under fluctuating electromagnetic field in the presence of a perfectly reflecting boundary. The noisy scheme of quantum teleportation affected by electromagnetic fluctuation is proposed. Then we calculate and investigate the behaviors of entanglement and fidelity, which are closely related to the plane boundary and atomic polarization. After a period of evolution, entanglement and fidelity evolve to zero and nonzero stable value respectively. Fidelity is closely related to the weight parameter and phase parameter of the teleported state. Besides, small two-atom separation makes entanglement and fidelity have better enhancement. Furthermore, the presence of boundary, atomic polarization and two-atom separation offers us more freedom to adjust the performance of the quantum teleportation. The results would give us new insight into quantum communication in an open quantum system since quantum teleportation plays an important role in quantum communication and quantum information.

Probabilistic secret sharing through noise quantum channe

2012 ◽  
Vol 12 (3&4) ◽  
pp. 253-261
Author(s):  
Satyabrata Adhikari ◽  
Indranil Chakrabarty ◽  
Pankaj Agrawal
Keyword(s):  
Quantum Information ◽  
Secret Sharing ◽  
Mixed State ◽  
Pure State ◽  
Noisy Channel ◽  
Noisy Channels ◽  
Superdense Coding ◽  
Classical Information ◽  
Phase Damping ◽  
Realistic Situation

In a realistic situation, the secret sharing of classical or quantum information will involve the transmission of this information through noisy channels. We consider a three qubit pure state. This state becomes a mixed-state when the qubits are distributed over noisy channels. We focus on a specific noisy channel, the phase-damping channel. We propose a protocol for secret sharing of classical information with this and related noisy channels. This protocol can also be thought of as cooperative superdense coding. We also discuss other noisy channels to examine the possibility of secret sharing of classical information.

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 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.

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.

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