Implementing a Two‐Photon Three‐Degrees‐of‐Freedom Hyper‐Parallel Controlled Phase Flip Gate Through Cavity‐Assisted Interactions

Abstract

Hyper-parallel quantum information processing is a promising and beneficial research field. Herein, a method to implement a hyper-parallel controlled-phase-flip (hyper-CPF) gate for frequency-, spatial-, and time-bin-encoded qubits by coupling flying photons to trapped nitrogen vacancy (NV) defect centers is presented. The scheme, which differs from their conventional parallel counterparts, is specifically advantageous in decreasing against the dissipate noise, increasing the quantum channel capacity, and reducing the quantum resource overhead. The gate qubits with frequency, spatial, and time-bin degrees of freedom (DOF) are immune to quantum decoherence in optical fibers, whereas the polarization photons are easily disturbed by the ambient noise.

Measurement-device-independent quantum key distribution of multiple degrees of freedom of a single photon

“…The key step of our multiple-DOF MDI-QKD protocol is the HBSA. Such HBSA protocol was also used in realizing the high-capacity quantum secure direct communication [72] and constructing the two-photon three DOFs hyper-parallel controlled phase-flip gate [73]. However, the complete HBSA protocol adopted in our MDI-QKD protocol requires the cross-Kerr nonlinearity technique, which is still a challenge under current experimental condition.…”

High-Fidelity Photonic Three-Degree-of-Freedom Hyperparallel Controlled-Phase-Flip Gate

“…Hyperparallel quantum gates have attracted much attention in recent years due to their excellent properties. Up to now, some interesting protocols for implementing hyperparallel quantum gates have been proposed via photon-matter platforms [31][32][33][34][35][36], and the inevitable incomplete and imperfect photon-matter interactions are usually not taken into account.…”

“…In 2019, Lu et al [42] demonstrated a frequency-bin based CNOT gate. And in 2020, Wei et al [36] presented a hyperparallel CPF gate utilizing the frequency DOF together with the spatial-mode and time-bin DOFs of a two-photon system. Frequency-based entanglements were employed by Zeng and Zhu [43] to complete hyper-Bell analysis.…”

“…In 2011, Chen et al [56] introduced the interaction between the polarized single photon and the NV center confined in the WGM microtoroidal resonator (MTR). Utilizing the photon-NV interactions, where the realistic NV-cavity parameters are not taken into consideration, some interesting works on (hyperparallel) quantum gate have been presented [30,35,36,[57][58][59]. It is worthy to relax the necessary for high-Q cavity system, and to further improve the fidelity of the schemes in realistic environment by preventing the imperfect and incomplete photon-NV interactions.…”

Robust-fidelity hyperparallel controlled-phase-flip gate through microcavities

“…For example, different from polarization photons, the frequency, spatial, and time-bin photons are immune to the decoherence effects and the bit-flip errors in optical fibers. Moreover, hyperentangled states can be used to complete some tasks which are impossible to achieve with the single DOF, such as entanglement witness, 14) linear-optical Bell-state analysis, 15) and one-way quantum com-and hyper-Toffoli gates [25][26][27][28] have been proposed.…”