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Chong Li

Publications and source records attributed to Chong Li.

154 records · Page 9Linked to original sources
arXiv2010

Brake subharmonic solutions of first order Hamiltonian systems

In this paper, we mainly use the Galerkin approximation method and the iteration inequalities of the $L$-Maslov type index theory to study the properties of brake subharmonic solutions for the first order non-autonomous Hamiltonian systems. We prove that when the positive integers $j$ and $k$ satisfies the certain conditions, there exists a $jT$-periodic nonconstant brake solution $z_{j}$ such that $z_{j}$ and $z_{kj}$ are distinct.

math.DS↗
arXiv2010

Nonadiabatic geometric rotation of electron spin in a quantum dot by 2Pi hyperbolic secant pulses

In this paper, the geometric and dynamic phase components of overall phase induced by 2π hyperbolic secant pulses in a quantum dot is analyzed. The dependence of two phase components on the ratio of the Rabi frequency to the detuning is investigated. Numerical results indicate that only for one resonant pulse the induced overall phase is purely the geometric phase. With other values of the ratio the overall phase consists of a nonzero dynamic part. The effect of spin precession to decrease the dynamic phase is characterized and discussed by analytical and numerical techniques. Utilizing the symmetry relations of the phases, a scheme to eliminate the dynamic phase by multipulse control is proposed. By choosing the proper parameter for each pulse, the dynamic phases induced by different pulses cancel out. The total pure geometric phase varies from -π to π, which realizes the arbitrary geometric rotation of spin. Average fidelity is calculated and the effects of magnetic field and decay of the trion state are compared and discussed. The results show the crucial role of weak magnetic field for high fidelity (above 99.3%).

quant-ph↗
arXiv2007

A single photon produces general W state of N qubits and its application

Based on the Wu's scheme[1], We prepare the general N-qubit W state. We find that the concurrence of two qubits in general N-qubit W state is only related to their coefficients and we successfully apply the general N-qubit W state to quantum state transfer and quantum state prepare like that in two-qubit system.

quant-ph↗
arXiv2007

Quantum states transfer by the analogous Bell states

Transmitting quantum states by channels of analogous Bell states is studied in this paper. We analyse the transmitting process, constructed the probabilitic unitary operator, and gain the largest successful transfer quantum state probability.

quant-ph↗
arXiv2004

Certain quantum key distribution achieved by using Bell states

A new protocol for quantum key distribution based on entanglement swapping is presented. In this protocol, both certain key and random key can be generated without any loss of security. It is this property differs our protocol from the previous ones. The rate of generated key bits per particle is improved which can approach six bits (4 random bits and 2 certain bits) per four particles.

quant-ph↗
arXiv2003

A random quantum key distribution by using Bell states

We proposed a new scheme for quantum key distribution based on entanglement swapping. By this protocol \QTR{em}{Alice} can securely share a random quantum key with \QTR{em}{Bob}, without transporting any particle.

quant-ph↗
arXiv2001

Notation for general quantum teleportation

A new notation for the quantum teleportation of finite dimensional quantum state through a generally entangled quantum channel is introduced. For a given quantum channel an explict mathematical criterion that governs the faithful teleportation is presented.

quant-ph↗
arXiv2001

Quantum Entanglement of Photons in Doubled q-Fock Space

A doubled q-Fock space is constructed by introducing an idle mode system dual to the physical one under consideration. The quantum entanglements of photons in the squeezed states and thermal states based on the doubled q-Fock space are discussed.

quant-ph↗
arXiv2000

su(2) and su(1,1) displaced number states and their nonclassical properties

We study su(2) and su(1,1) displaced number states. Those states are eigenstates of density-dependent interaction systems of quantized radiation field with classical current. Those states are intermediate states interpolating between number and displaced number states. Their photon number distribution, statistical and squeezing properties are studied in detail. It is show that these states exhibit strong nonclassical properties.

quant-ph↗