Recently, Harrow et al. [Phys. Rev. Lett. 92 ( 2004) 187901] gave a method for preparing an arbitrary quantum state with high success probability by physically transmitting some qubits, and by consuming a maximally en...
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Recently, Harrow et al. [Phys. Rev. Lett. 92 ( 2004) 187901] gave a method for preparing an arbitrary quantum state with high success probability by physically transmitting some qubits, and by consuming a maximally entangled state, together with exhausting some shared random bits. In this paper, we discover that some states are impossible to be perfectly prepared by Alice and Bob initially sharing some entangled states. In particular, we present a sufficient and necessary condition for the states being enabled to be exactly prepared with probability equal to unity, in terms of the initial entangled states (maybe nonmaximally). In contrast, if the initially shared entanglement is maximal, then the probabilities for preparing these quantum states are smaller than unity. Furthermore, the lower bound on the probability for preparing some states are derived.
We discuss a scheme for a full superdense coding of entangled photon states employing only linear optics elements. By using the mixed basis consisting of four states that are unambiguously distinguishable by a standar...
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We discuss a scheme for a full superdense coding of entangled photon states employing only linear optics elements. By using the mixed basis consisting of four states that are unambiguously distinguishable by a standard and polarizing beam splitters we can deterministically transfer four messages by manipulating just one of the two entangled photons. The sender achieves the determinism of the transfer either by giving up the control over 50% of sent messages (although known to her) or by discarding 33% of incoming photons.
Modified superdense coding for quantum systems was introduced for two communicating parties. In this paper the algorithm is extended to n parties. Beside the generalization, an analytical approach is also presented to...
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ISBN:
(纸本)9781467379397
Modified superdense coding for quantum systems was introduced for two communicating parties. In this paper the algorithm is extended to n parties. Beside the generalization, an analytical approach is also presented to show the performance of the algorithm, along with the comparison of slotted ALOHA systems.
The utility of a five-qubit entangled state for quantum teleportation, quantum state sharing and superdense coding is investigated. The state can be utilized for perfect teleportation and quantum state sharing of an a...
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The utility of a five-qubit entangled state for quantum teleportation, quantum state sharing and superdense coding is investigated. The state can be utilized for perfect teleportation and quantum state sharing of an arbitrary single- and two-qubit state. The capacity of superdense coding of the state reaches the "Holevo bound", which means that five classical bits can be transmitted by sending three qubits. The preparation of the five-qubit state and detection of the multipartite states in cavity QED are discussed. The distinct advantage of the feasible cavity QED technology that we use is insensitive to the thermal field and the cavity decay.
We have conceived a near-capacity code design for entanglement-assisted classical communication over the quantum depolarizing channel. The proposed system relies on efficient near-capacity classical code designs for a...
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We have conceived a near-capacity code design for entanglement-assisted classical communication over the quantum depolarizing channel. The proposed system relies on efficient near-capacity classical code designs for approaching the entanglement-assisted classical capacity of a quantum depolarizing channel. It incorporates an Irregular Convolutional Code (IRCC), a Unity Rate Code (URC) and a soft-decision aided superdense Code (SD), which is hence referred to as an IRCC-URC-SD arrangement. Furthermore, the entanglement-assisted classical capacity of an N-qubit superdense code transmitted over a depolarizing channel is invoked for benchmarking. It is demonstrated that the proposed system operates within 0.4 dB of the achievable noise limit for both 2-qubit as well as 3-qubit SD schemes. More specifically, our design exhibits a deviation of only 0.062 and 0.031 classical bits per channel use from the corresponding 2-qubit and 3-qubit capacity limits, respectively. The proposed system is also benchmarked against the classical convolutional and turbo codes.
We revisit the problem of conveying classical messages by transmitting quantum states, and derive new, optimal bounds on the number of quantum bits required for this task. Much of the previous work on this problem, an...
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We revisit the problem of conveying classical messages by transmitting quantum states, and derive new, optimal bounds on the number of quantum bits required for this task. Much of the previous work on this problem, and on other communication tasks in the setting of bounded error entanglement-assisted communication, is based on sophisticated information theoretic arguments. Our results are derived from first principles, using a simple linear algebraic technique. A direct consequence is a tight lower bound for the Inner Product function that has found applications to privacy amplification in quantum key distribution protocols.
Symbol-based iterative decoding is proposed for the transmission of classical Markov source signals over a quantum channel using a three-stage serial concatenation of a convolutional code (CC), a unity-rate code and a...
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Symbol-based iterative decoding is proposed for the transmission of classical Markov source signals over a quantum channel using a three-stage serial concatenation of a convolutional code (CC), a unity-rate code and a two-qubit superdense (SD) protocol. A modified symbol-based maximum a posteriori algorithm is employed for CC decoding to exploit the Markov source statistics during the iterative decoding process. Extrinsic information transfer chart analysis is performed to evaluate the benefit of the extrinsic mutual information gleaned from the CC decoder for sources with different correlations. We evaluate the bit error rate performance of the proposed coding scheme and compare it with the relevant benchmark schemes, including the turbo coding-based SD scheme. We demonstrate that a near-capacity performance can be achieved using the proposed scheme and when utilizing sources having a high correlation coefficient of rho = 0.9, the proposed coding scheme performs within 0.53 dB from the entanglement-assisted classical capacity.
During the last 30 years the scientific community has coexisted with the most fascinating protocol due to Quantum Physics: quantum teleportation, which would have been impossible if quantum entanglement, so questioned...
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During the last 30 years the scientific community has coexisted with the most fascinating protocol due to Quantum Physics: quantum teleportation, which would have been impossible if quantum entanglement, so questioned by Einstein, did not exist. In this work, a complete architecture for the teleportation of Computational Basis States (CBS) is presented. Such CBS will represent each of the possible 24 classical bits commonly used to encode every pixel of a 3-color-channel image (red-green-blue, or cyan-yellow-magenta). For this purpose, a couple of interfaces: classical-to-quantum and quantum-to-classical are presented with two versions of the teleportation protocol: standard and simplified.
We present a quantum teleportation scheme for single qubits, qutrits, and ququads using maximally entangled pairs of two ququads. Additionally, we demonstrate that, under a specific mapping, single ququad teleportatio...
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We present a quantum teleportation scheme for single qubits, qutrits, and ququads using maximally entangled pairs of two ququads. Additionally, we demonstrate that, under a specific mapping, single ququad teleportation is equivalent to two-qubit teleportation using generalized Bell states. Furthermore, we establish a dense (superdense) coding scheme for sending four bits of classical information using a single ququad state. We also investigate the efficiency of the single ququad quantum teleportation scheme by studying the fidelity of teleportation when subjected to noise, such as amplitude damping, depolarizing channel, phase damping, and bit flip. Finally, we investigate noise effects in two qubit teleportation and compare its results with the ququad case. We observe that in both cases, adding more noise increases the fidelity of teleportation. Additionally, we show that qubit teleportation is more resilient to noise than ququad teleportation.
As an important branch of quantum secure multiparty computation, quantum private comparison (QPC) has attracted more and more attention recently. In this paper, according to the quantum implementation mechanism that t...
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As an important branch of quantum secure multiparty computation, quantum private comparison (QPC) has attracted more and more attention recently. In this paper, according to the quantum implementation mechanism that these protocols used, we divide these protocols into three categories: The quantum cryptography QPC, the superdense coding QPC, and the entanglement swapping QPC. And then, a more in-depth analysis on the research progress, design idea, and substantive characteristics of corresponding QPC categories is carried out, respectively. Finally, the applications of QPC and quantum secure multi-party computation issues are discussed and, in addition, three possible research mainstream directions are pointed out.
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