Dazu Huang

Bidirectional Quantum Secure Direct Communication Based on Entanglement

Based on entanglement,a bidirectional quantum secure direct communication scheme is proposed to exchange directly the communicators’ secret messages . In this scheme the messages are encoded in the entanglement state. our scheme has great capacity to distribute the secret messages since these messages have been imposed on high-dimensional Bell states via the local unitary operations with superdense coding. Security analysis indicates that this scheme is secure against the present Trojan horse attack and the current attack strategyand it can also ensure the security of the messages in a low noisy channel.

Quantum Key Distribution Based on Multi-qubit Hadamard Matrices

A deterministic one-step quantum key distribution scheme is proposed based on multi-qubit Hadamard matrices. In our proposed scheme, the secret key, which is encoded and decoded by using multi-qubit Hadamard transform, is deterministic. In addition, we also discuss in some detail how this protocol must be carefully designed for correcting errors and checking eavesdropping. This protocol is secure under the well-known assumption that the classical channel cannot be modified. It also has an advantage of not exchanging any other classical information except for eavesdropping check.

Quantum error-correction codes based on multilevel constructions of hadamard matrices

To achieve quantum error-correction codes with good parameters, the recursive constructions of Hadamard matrices with even length are proposed with special characters. The generators of the stabilizer of the designed codes can be constructed by selecting some rows from these matrices, hence several codes are obtained expediently via the stabilizer quantum codes constructions. Some of the presented codes are unsurpassed by the previously published codes.

Fast Jacket-Haar Transform with Any Size

Jacket-Haar transform has been recently generalized from Haar transform and Jacket transform, but, unfortunately, it is not available in a case where the length is not a power of 2. In this paper, we have proposed an arbitrary-length Jacket-Haar transform which can be conveniently constructed from the 2-point generalized Haar transforms with the fast algorithm, and thus it can be constructed with any sizes. Moreover, it can be further extended with elegant structures, which result in the fast algorithms for decomposing. We show that this approach can be practically applied for the electrocardiogram (ECG) signal processing. Simulation results show that it is more efficient than the conventional fast Fourier transform (FFT) in signal processing.

Small Scale Quantum Network Communications via Multi-step Quantum Teleportation

Motivated by multi-step quantum teleportation of single-qubit states and two-qubit states with entanglement swapping, we present a small scale quantum network communication scheme based on entanglement of Bell states. In this scheme, it contains certain number of single-qubit quantum source nodes that teleport unknown quantum states to other nodes in the network in the multi-teleport fashion where every intermediate node can pass on any of its received quantum information to others via multi-step quantum teleportation. It makes legal nodes more convenient than any other previous schemes to transmit unknown quantum states to unknown participants in practical applications. The security of this scheme is based on the securely-shared quantum channels between all nodes.

Erratum to: Quantum Quasi-Cyclic Low-Density Parity-Check Codes

The paper entitled ”Quantum Quasi-Cyclic Low-Density Parity-Check Codes”, on pages 18-27 of this volume, has been retracted, because a large portion of the contents had been taken from the paper “Quantum Quasi-Cyclic LDPC Codes” by Manabu Hagiwara and Hideki Imai, published by arXiv.org in the year 2007.

Retracted: Quantum Quasi-Cyclic Low-Density Parity-Check Codes

In this paper, how to construct quantum quasi-cyclic (QC) low-density parity-check (LDPC) codes is proposed. Using the proposed approach, some new quantum codes with various lengths and rates of no cycles-length 4 in their Tanner graph are designed. In addition, the presented quantum codes can be efficiently constructed with large codeword length. Finally, we show the decoding of the proposed quantum QC LDPC.

Deterministic quantum cryptographic communication with entanglement state

A quantum cryptographic communication protocol with entanglement state is proposed to distribute secret messages deterministically. In this scheme the messages are encoded in the particles of the Einstein-Podolsky-Rosen (EPR) pairs rotated random polarization angles by applying random and independent operations. Security analysis indicates that this scheme is secure against the present Trojan horse attack strategy and the impersonation attack strategy, and it can also ensure the security of the messages in a low noisy channel. Moreover, it has an advantage that communication can be launched by the sender just like an actual communication system.

Deterministic Secure Bidirectional Quantum Communication

Based on single photons with random polarization angel, a deterministic secure bidirectional quantum communication scheme, which is similar to traditional communication mode, is proposed. In this scheme both checking messages and secret messages are encoded in the single photons rotated random polarization angle by performing a series of independent operations in three-way quantum channel. Security analysis shows that this scheme, in which secret messages are transmitted deterministically in arbitrary direction (bidirection or monodirection) between two legal communicators, is secure against the present Trojan horse attack strategy and the impersonation attack strategy in a low noisy channel.

Multilevel Quantum Error Correction Codes in Transform Domain

Quantum error correction codes (QECC) have become cornerstone of quantum information and computation. In this correspondence, we investigate a class of QECC in transform domain. To design the QECC denoted by [[N, k, d]] with larger N, generators of stabilizer of the constructed codes are composed via selecting randomly N - k rows from an yielded matrices with recursive relations of matrices transform. Subsequently, a new kind of stabilizer quantum codes may be generated expediently. In the proposed approach, the parameter N may be arbitrary larger, and the QECC with larger N may be easily constructed due to the employment of the recursive relations of matrices transform. Especially, some new codes, which are impossible to be obtained via the previous approaches, are constructed. The resulting codes are more efficient with better perimeters than the previous quantum codes.