2,249 research outputs found
Many-agent controlled teleportation of multi-qubit quantum information
We present a general idea to construct methods for multi-qubit quantum
teleportation between two remote parties with control of many agents in the
network. Our methods seem to be much simpler than the existing method proposed
recently (Phys. Rev. A {\bf 70}, 022329(2004)). We then demonstrate our idea by
using several different protocols of quantum key distribution, including Ekert
91 and the deterministic secure communication protocol raised by Deng and Long.Comment: This paper has been accepted for publication in Phys. Lett.
Robust Spin Squeezing Preservation in Photonic Crystal Cavities
We show that the robust spin squeezing preservation can be achieved by
utilizing detuning modification for an ensemble of N separate two-level atoms
embedded in photonic crystal cavities (PCC). In particular, we explore the
different dynamical behaviors of spin squeezing between isotropic and
anisotropic PCC cases when the atomic frequency is inside the band gap. In both
cases, it is shown that the robust preservation of spin squeezing is completely
determined by the formation of bound states. Intriguingly, we find that unlike
the isotropic case where steady-state spin squeezing varies smoothly when the
atomic frequency moves from the inside to the outside band edge, a sudden
transition occurs for the anisotropic case. The present results may be of
direct importance for, e.g., quantum metrology in open quantum systems.Comment: 6 pages, 4 figures, accepted by Laser Physics Letter
Multiparty Quantum Secret Sharing
Based on a quantum secure direct communication (QSDC) protocol [Phys. Rev.
A69(04)052319], we propose a -threshold scheme of multiparty quantum
secret sharing of classical messages (QSSCM) using only single photons. We take
advantage of this multiparty QSSCM scheme to establish a scheme of multiparty
secret sharing of quantum information (SSQI), in which only all quantum
information receivers collaborate can the original qubit be reconstructed. A
general idea is also proposed for constructing multiparty SSQI schemes from any
QSSCM scheme
Role of in the reaction near threshold
The role of the resonance in the reaction near threshold is studied within an effective Lagrangian
approach. We perform a calculation for the total and differential cross section
of the reaction by including the contributions
from the intermediate state decaying into
dominated by and mesons exchanges, the nucleon pole and
resonance decaying into dominated by exchanges of
and mesons. Besides, the non-resonance process and contact terms
to keep the total scattering amplitude gauge invariant are also considered.
With our model parameters, the total cross section of this reaction is of the
order of nanobarn at photon beam energy GeV. It is
expected that our model predictions could be tested by future experiments.Comment: Published versio
- …