Annulled van der Waals interaction and fast Rydberg quantum gates

Shi, Xiaojie; Kennedy, Tom

doi:10.1103/physreva.95.043429

Cited by 31 publications

(34 citation statements)

References 58 publications

(109 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Below, we show results when the Rabi frequencies have phase noise as described in Eq. (51). The time-dependent phase φ(t) in Eq.…”

Section: Doppler Dephasing and Variation Of Vdwi In A Thermal Opticalmentioning

confidence: 99%

See 1 more Smart Citation

Fast, Accurate, and Realizable Two-Qubit Entangling Gates by Quantum Interference in Detuned Rabi Cycles of Rydberg Atoms

Shi

2019

Phys. Rev. Applied

Self Cite

View full text Add to dashboard Cite

High-fidelity entangling quantum gates based on Rydberg interactions are required for scalable quantum computing with neutral atoms. Their realization, however, meets a major stumbling block -the motion-induced dephasing of the transition between the ground and Rydberg states. By using quantum interference between different detuned Rabi oscillations, we propose a practical scheme to realize a class of accurate entangling Rydberg quantum gates subject to a minimal dephasing error. We show two types of such gates, U1 and U2, in the form of diag{1, e iα , e iγ , e iβ }, where α, γ, and β are determined by the parameters of lasers and the Rydberg blockade V . U1 is realized by sending to the two qubits a single off-resonant laser pulse, while U2 is realized by individually applying one pulse of detuned laser to each qubit. One can construct the controlled-z (CZ) gate from several U1 when assisted by single-qubit rotations and phase gates, or from two U2 and two phase gates. Our method has several advantages. First, the gates are accurate because the fidelity of U k is limited only by a rotation error below 10 −5 and the Rydberg-state decay. Decay error on the order of 10 −5 can be easily obtained because all transitions are detuned, resulting in small population in Rydberg state. Second, the motion-induced dephasing is minimized because there is no gap time in which a population is left in the Rydberg shelving states of either qubit. Third, the gate is resilient to the variation of V . This is because among the three phases α, γ, and β, only the last has a (partial) dependence on V . Fourth, the Rabi frequency and V in our scheme are of similar magnitude, which permits a fast implementation of the gate when both of them are of the feasible magnitude of several megahertz. The rapidity, accuracy, and feasibility of this interference method can lay the foundation for entangling gates in universal quantum computing with neutral atoms.

show abstract

“…Below, we show results when the Rabi frequencies have phase noise as described in Eq. (51). The time-dependent phase φ(t) in Eq.…”

Section: Doppler Dephasing and Variation Of Vdwi In A Thermal Opticalmentioning

confidence: 99%

“…10, we have used the enhanced spectral density in Eq. (51). But if it is reduced by several orders, for example, according to the dark gray curve of Fig.…”

Section: Prospects For High-fidelity Gatesmentioning

confidence: 99%

Fast, Accurate, and Realizable Two-Qubit Entangling Gates by Quantum Interference in Detuned Rabi Cycles of Rydberg Atoms

Shi

2019

Phys. Rev. Applied

Self Cite

View full text Add to dashboard Cite

show abstract

“…We consider the condition where |r c1 and |r t are Rydberg eigenstates, while |r c2 is a superposition state constructed from two different Rydberg eigenstates; as shown in Ref. [44], it is possible to choose appropriate superposition in |r c2 so that the two-atom state |r c1 r c2 has a zero C-six vdWI coefficient, thus experiences an exact zero vdWI, but the interactions of the states |r c1 r t and |r c2 r t are still normally significant. In this case, there will be no phase accumulation for the states |r c1 r c2 0 and |r c1 r c2 1 for the input states |000 and |001 , respectively, while the necessary blockade interaction between the control and target qubits can still arise during pulses 2-4, thus the Deutsch gate can still be realized.…”

Section: Remove Phase Accumulation Formentioning

confidence: 99%

“…As shown in Ref. [44], strong microwave fields should be used to protect the superposition state |r c2 against vdWI-induced decay.…”

Section: Remove Phase Accumulation Formentioning

confidence: 99%

Deutsch, Toffoli, and cnot Gates via Rydberg Blockade of Neutral Atoms

Shi

2018

Phys. Rev. Applied

Self Cite

View full text Add to dashboard Cite

Universal quantum gates and quantum error correction (QEC) lie in the heart of quantum information science. Large-scale quantum computing depends on a universal set of quantum gates, in which some gates may be easily carried out, while others are hard with a certain physical system. There is a unique three-qubit quantum gate called the Deutsch gate [D(θ)], from which alone a circuit can be constructed so that any feasible quantum computing is attainable. As far as we know, however, D(θ) has not been demonstrated. Here we design an easily realizable D(θ) by using Rydberg blockade of neutral atoms, where θ can be tuned to any value in [0, π] by adjusting the strengths of external control fields. Using similar protocols, we further show that both the Toffoli and CNOT gates can be achieved with only three laser pulses. The Toffoli gate, being universal for classical reversible computing, is also useful for QEC that plays an important role in quantum communication and fault-tolerant quantum computation. The possibility and briefness to realize these gates shed new light on the study of quantum information with neutral atoms.

show abstract

“…The second application of two-step modulation is to prepare desired superposition of two Rydberg states: |ψ = cos ϑ |62D 3/2 + sin ϑ |63P 1/2 , which is exploited for fast Rydberg quantum gate [55]. In the experiment [49], |ψ is achieved by several operation steps, including switching off and on the laser fields and the microwave field in sequence.…”

Section: Applications In Rydberg Systemsmentioning

confidence: 99%

Quantum state engineering by periodical two-step modulation in an atomic system

et al. 2018

View full text Add to dashboard Cite

By periodical two-step modulation, we demonstrate that the dynamics of multilevel system can still evolve even in multiple large detunings regime, and provide the effective Hamiltonian (of interest) for this system. We then illustrate this periodical modulation in quantum state engineering, including achieving direct transition from the ground state to the Rydberg state or the desired superposition of two Rydberg states without satisfying two-photon resonance condition, switching between Rydberg blockade regime and Rydberg antiblockade regime, stimulating distinct atomic transitions by the same laser field, and implementing selective transitions in the same multilevel system. Particularly, it is robust against perturbation of control parameters. Another advantage is that the waveform of laser field has simple square-wave form which is readily implemented in experiments. Thus, it offers us a novel method of quantum state engineering in quantum information processing.

show abstract

Annulled van der Waals interaction and fast Rydberg quantum gates

Cited by 31 publications

References 58 publications

Fast, Accurate, and Realizable Two-Qubit Entangling Gates by Quantum Interference in Detuned Rabi Cycles of Rydberg Atoms

Fast, Accurate, and Realizable Two-Qubit Entangling Gates by Quantum Interference in Detuned Rabi Cycles of Rydberg Atoms

Deutsch, Toffoli, and cnot Gates via Rydberg Blockade of Neutral Atoms

Quantum state engineering by periodical two-step modulation in an atomic system

Contact Info

Product

Resources

About