Source-linked AI summary
Quantifying photonic high-dimensional entanglement
Anthony Martin, Thiago Guerreiro, Alexey Tiranov, Sébastien Designolle, Florian Fröwis, Nicolas Brunner, Marcus Huber, Nicolas Gisin
TL;DR
Certifying how much entanglement a high-dimensional state contains is difficult when experimental data are sparse. This paper applies theoretical lower-bound methods to photonic temporal-mode pairs, certifying 2.09(7) ebits in time-bin encoding and 4.1(1) ebits in energy-time encoding.
Problem
Certifying the amount of entanglement in high-dimensional states is challenging: standard tomography requires many measurements, while alternatives may rely on extra assumptions such as high purity.
Source: p. 1Method
The authors use sparse experimental data and theoretical methods to lower-bound entanglement of formation, with an SDP solution representing a valid density matrix compatible with the data.
Source: pp. 1–3Results
The time-bin experiment certifies 2.09(7) ebits, and the energy-time experiment certifies 4.1(1) ebits of entanglement of formation.
Source: pp. 3–5Takeaways & Limitations
The results demonstrate the potential of temporal entanglement as a platform for creating and certifying quantum states with a large amount of entanglement.
Source: p. 1Certifying higher entanglement by adding temporal modes and measuring more off-diagonal elements would require interferometer path differences up to 70 cm, which is impractical in this configuration.
Source: p. 3
Abstract
from arXiv · showhide
High-dimensional entanglement offers promising perspectives in quantum information science. In practice, however, the main challenge is to devise efficient methods to characterize high-dimensional entanglement, based on the available experimental data which is usually rather limited. Here we report the characterization and certification of high-dimensional entanglement in photon pairs, encoded in temporal modes. Building upon recently developed theoretical methods, we certify an entanglement of formation of 2.09(7) ebits in a time-bin implementation, and 4.1(1) ebits in an energy-time implementation. These results are based on very limited sets of local measurements, which illustrates the practical relevance of these methods.