Counterfactual Measurements and the Quantum Zeno Effect

Onofrio L. Russo, Oktay H. Gokce

Tianyi Xing, Anqi Huang, Yizhi Wang +10 more

ABSTRACT The quantum Zeno effect, which inhibits quantum state evolution via repeated weak measurements, significantly enhances the efficiency of interaction‐free measurement (IFM). This fundamental mechanism facilitates high‐efficiency counterfactual quantum communication, enabling information delivery without particle transmission through the channel. However, the transmission time of the counterfactual communication requires minutes for bit and suffers the bit error when transmitting an image. Applying the quantum Zeno effect, we experimentally demonstrate high‐efficiency weak‐trace‐free counterfactual communication on a quantum photonic chip, achieving a transmission probability of 74.2 1.6% for bit 0 and 85.1 1.3% for bit 1. Furthermore, we successfully transmit our group's logo – Quanta – through counterfactual communication, and reduce the time cost from minutes to seconds for bit, with zero bit errors after information processing. Our study provides a promising approach for secure and efficient communication using integrated silicon quantum photonics.

Kazuki Koshino, Akira Shimizu

Chao Liu, Jinhong Liu, Junxiang Zhang +1 more

We present an interaction-free measurement with quantum Zeno effect and a high efficiency η = 74.6% ± 0.15%. As a proof-of-principle demonstration, this measurement can be used to implement a quantum counterfactual-like communication protocol. Instead of a single photon state, we use a coherent light as the input source and show that the output agrees with the proposed quantum counterfactual communication protocol according to Salih et al. Although the counterfactuality is not achieved due to the presence of a few photons in the public channel, we show that the signal light is nearly absent in the public channel, which exhibits a proof-of-principle quantum counterfactual-like property of communication.

Fakhar Zaman, Youngmin Jeong, Hyundong Shin

The Bell-state analysis to distinguish between the four maximally entangled Bell states requires the joint measurement on entangled particles. However, spatially separated parties cannot perform the joint measurement. In this paper, we present a counterfactual Bell-state analysis based on the chained quantum Zeno effect. This counterfactual analysis not only enables us to perform a complete Bell-state analysis, but also enables spatially separated parties to distinguish between the four Bell states without transmitting any physical particle over the channel.

M. A. B. Whitaker