We achieve the robust nonadiabatic holonomic two-qubit controlled gate in one step based on the groundstate blockade mechanism between two Rydberg atoms. By using the Rydberg-blockade effect and the Raman transition m...We achieve the robust nonadiabatic holonomic two-qubit controlled gate in one step based on the groundstate blockade mechanism between two Rydberg atoms. By using the Rydberg-blockade effect and the Raman transition mechanism, we can produce the blockade effect of double occupation of the corresponding ground state,i.e., ground-state blockade, to encode the computational subspace into the ground state, thus effectively avoiding the spontaneous emission of the excited Rydberg state. On the other hand, the feature of geometric quantum computation independent of the evolutionary details makes the scheme robust to control errors. In this way,the controlled quantum gate constructed by our scheme not only greatly reduces the gate infidelity caused by spontaneous emission but is also robust to control errors.展开更多
Twist-and-stack engineering provides a programmable degree of freedom for nonlinear optics in two-dimensional materials,yet in a homostructure whose constituents have no second harmonic generation(SHG),how interlayer ...Twist-and-stack engineering provides a programmable degree of freedom for nonlinear optics in two-dimensional materials,yet in a homostructure whose constituents have no second harmonic generation(SHG),how interlayer coupling grants and tunes second-order response remains unclear.Here,we use twisted monolayer-bilayer graphene(t(1+2)LG)and combine microscopic SHG spectroscopy with first-principles differential charge-density analysis to establish a unified"permission-and-resonance"mechanism.Interlayer coupling creates an interlayer charge imbalance within the AB-stacked bilayer,breaking inversion symmetry and thereby permitting an in-plane electric-dipole response.At the same time,the twist angle steers van Hove singularities in the band structure to achieve two-photon resonance,which markedly amplifies the susceptibilityχ^((2)).Experimentally,atθ=13.5°,we obtainχ^((2))=279.4 pm/V,evidencing a highly efficient second-order response.These results identify SHG as a sensitive probe of interlayer coupling and charge redistribution in homostructure van der Waals systems.展开更多
基金supported by the Special Project for Research and Development in Key Areas of Guangdong Province(Grant No.2020B0303300001)the National Natural Science Foundation of China(Grant Nos.U21A20434 and 12074346)the Natural Science Foundation of Henan Province(Grant No.212300410085)。
文摘We achieve the robust nonadiabatic holonomic two-qubit controlled gate in one step based on the groundstate blockade mechanism between two Rydberg atoms. By using the Rydberg-blockade effect and the Raman transition mechanism, we can produce the blockade effect of double occupation of the corresponding ground state,i.e., ground-state blockade, to encode the computational subspace into the ground state, thus effectively avoiding the spontaneous emission of the excited Rydberg state. On the other hand, the feature of geometric quantum computation independent of the evolutionary details makes the scheme robust to control errors. In this way,the controlled quantum gate constructed by our scheme not only greatly reduces the gate infidelity caused by spontaneous emission but is also robust to control errors.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12574339,12574457,and 12174207)Tianjin Science and Technology Project(Grant No.24ZXZSSS00120)。
文摘Twist-and-stack engineering provides a programmable degree of freedom for nonlinear optics in two-dimensional materials,yet in a homostructure whose constituents have no second harmonic generation(SHG),how interlayer coupling grants and tunes second-order response remains unclear.Here,we use twisted monolayer-bilayer graphene(t(1+2)LG)and combine microscopic SHG spectroscopy with first-principles differential charge-density analysis to establish a unified"permission-and-resonance"mechanism.Interlayer coupling creates an interlayer charge imbalance within the AB-stacked bilayer,breaking inversion symmetry and thereby permitting an in-plane electric-dipole response.At the same time,the twist angle steers van Hove singularities in the band structure to achieve two-photon resonance,which markedly amplifies the susceptibilityχ^((2)).Experimentally,atθ=13.5°,we obtainχ^((2))=279.4 pm/V,evidencing a highly efficient second-order response.These results identify SHG as a sensitive probe of interlayer coupling and charge redistribution in homostructure van der Waals systems.
