Faithful and efficient hyperentanglement purification for spatial-polarization-time-bin photon system

Abstract

We present a faithful and efficient hyperentanglement purification protocol (hyper-EPP) for nonlocal two-photon systems in spatial-polarization-time-bin hyperentangled Bell states. As the single-photon detectors can detect and herald the undesirable properties caused by the side leakage and the finite coupling strength, the parity-check gates and SWAP gates of our hyper-EPP in the spatial, the polarization, and the time-bin modes degrees of freedom (DoFs) work faithfully. The qubit-flip errors on photon systems in three DoFs can be corrected effectively with the faithful parity-check gates and the photon pairs can reuse to distill high-fidelity ones by introducing the faithful SWAP gates, which greatly increases the efficiency of our hyper-EPP. Further, the maximal hyperentanglement can be obtained in principle by operating the hyper-EPP multiple rounds.

Complete analysis of hyperentangled Bell state in three degrees of freedom using Kerr effect and self-assisted mechanism

“…As a counterintuitive phenomenon in the physical world, quantum entanglement is the core resource that enables quantum information technologies, such as quantum teleportation [1], quantum dense coding [2], entanglement swapping [3], quantum imaging [4], and other such tasks. A quantum system simultaneously entangled in more than one degree of freedom (DOF) is known as hyperentanglement [5], which has been widely exploited for high-capacity quantum computation and quantum communication [6][7][8][9][10][11][12]. One of the most important applications of hyperentanglement is that it can be used for the complete Bell state analysis (BSA) [13][14][15].…”

Compact entanglement concentration for three-electron-spin W states with error-detected parity-check gates

“…One trenchant method to prevent the degradation of entanglement is entanglement concentration protocol (ECP), which is used to distill maximally entangled states from partially entangled pure states, in particular the imperfect entangled source or decoherence of entanglement from the storage process. Another efficacious one is entanglement purification protocol (EPP), which is used to increase the fidelity of required maximally entangled state in mixed entangled state, including EPPs based on controlled-not gate (or parity check gate, PCG) [24][25][26][27][28][29][30][31][32][33][34][35], deterministic EPPs [36][37][38], measurementbased EPPs [39][40][41][42][43], and hyperentanglement-assisted EPPs [44][45][46], which is applied to get maximally entangled states with higher fidelity from the mixed entangled states.…”

Complete conversion of KLM entanglement to GHZ entanglement with error-detected quantum devices

“…uantum entanglement on account of quantum mechanics plays an important role in diverse quantum information technologies (QITs), such as distributed quantum computation, [1][2][3][4] quantum key distribution, 5,6) quantum state analysis, [7][8][9][10] quantum gates, [11][12][13] and quantum secure direct communication. [14][15][16][17] Moreover, in contrast to two-particle entanglement, multipartite entanglement demonstrates distinct properties not only to reflect the nonlocality and nonclassicality of quantum physics, 18) but also to carry out many useful quantum protocols where more than two parties tightly come together.…”