Multi-particle and High-dimension Controlled Order Rearrangement Encryption Protocols

Based on the controlled order rearrange encryption (CORE) for quantum key distribution using EPR pairs[Fu.G.Deng and G.L.Long Phys.Rev.A68 (2003) 042315], we propose the generalized controlled order rearrangement encryption (GCORE) protocols of $N$ qubits and $N$ qutrits, concretely display them in the cases using 3-qubit, 2-qutrit maximally entangled basis states. We further indicate that our protocols will become safer with the increase of number of particles and dimensions. Moreover, we carry out the security analysis using quantum covariant cloning machine for the protocol using qutrits. Although the applications of the generalized scheme need to be further studied, the GCORE has many distinct features such as great capacity and high efficiency

Probing dark particles indirectly at the CEPC

When dark matter candidate and its parent particles are nearly degenerate, it would be difficult to probe them at the Large Hadron Collider directly. We propose to explore their quantum loop effects at the CEPC through the golden channel process $e^+e^-\to \mu^+\mu^-$. We use a renormalizable toy model consisting of a new scalar and a fermion to describe new physics beyond the Standard Model. The new scalar and fermion are general multiplets of the $SU(2)_L\times U(1)_Y$ symmetry, and couple to the muon lepton through Yukawa interaction. We calculate their loop contributions to anomalous $\gamma\mu^+\mu^-$ and $Z\mu^+\mu^-$ couplings which can be applied to many new physics models. The prospects of their effects at the CEPC are also examined assuming a 0.002 accuracy in the cross section measurement