Measurement‐Based Hyperentanglement Distillation for Lossy and Distortion Photon State

Abstract

The information content of a photon system can be extended by hyperentanglement, but the quality of hyperentanglement will be decreased by the complicated transmission loss and channel noise in quantum information processing. Here, an efficient measurement-based hyperentanglement distillation protocol (MB-HDP) is presented for depressing the effects of complicated transmission loss and channel noise on hyperentanglement. In the MB-HDP, the nonlocal lossy and distortion photon states are coupled to local hyperentangled Greenberger-Horne-Zeilinger (GHZ) states using parity measurement and qubit amplification device, and the decoherence caused by bit-flip (phase-flip) error, diverse transmission coefficients and transmission loss can be depressed by the successful measurement results, which can increase the quality of nonlocal hyperentangled photon state. This MB-HDP broadens the application scope of hyperentanglement distillation to nonlocal lossy and distortion photon state with a lower degree of entanglement. In addition, the MB-HDP can further improve the quality of nonlocal hyperentangled photon state by coupling multiple copies of lossy and distortion hyperentangled photon state with local hyperentangled GHZ states. This work demonstrates the ability of measurement-based method for ensuring the quality of nonlocal hyperentanglement, which can improve the integrity and capacity of long-distance quantum information processing.

Purification for Hybrid Entanglement between Discrete‐ and Continuous‐Variable States

“…It plays a vital role in quantum communication and computation fields, such as quantum teleportation, [1][2][3] quantum key distribution, [4][5][6][7][8][9] quantum secret sharing, [10][11][12][13] quantum secure direct communication, [14][15][16][17][18][19][20][21][22] quantum repeater, [23,24] distributed quantum computing, [25] quantum machine learning, [26] and some other important branches. [27][28][29][30][31][32][33][34][35][36] Practical quantum applications commonly operate across diverse physical systems. In general, the quantum applications can be historically divided into two primary categories: continuousvariable (CV) and discrete-variable (DV) systems.…”

Universal Highly Effective Entanglement Purification with Single‐Copy Hyperentangled State

“…Entanglement purification is a useful way to share high-quality entangled state among remote users, which can distill high-fidelity entangled states from a set of mixed states with less entanglement. [28][29][30][31][32][33][34][35][36][37][38][39][40] Bennett et al [28] first proposed the entanglement purification protocols (EPPs) using bilateral synchronous quantum controlled-not (CNOT) gate operations and classical communication, including recurrence protocol and hashing (breeding) protocol. Hashing protocol and breeding protocol are effective for purifying ensembles of mixed entangled states with high fidelity in the asymptotic limit, which involve local gates performed on pairs of mixed entangled states and measurements to extract information about the entangled states.…”