QKD: Add note on heartbeat

chapter-qkd/chapter.tex

@@ -734,6 +734,7 @@ requirement is feeding through a number of fibers for its various input and outp
 different from any server or other piece of IT equipment. In the following section, we will present a design that
 provides a combined power and multi-fiber passthrough that is sufficient for QKD applications before concluding with an
 analysis of post-quantum heartbeat signal security.
+% FIXME stuff on heartbeat
 
 \subsection{Multi-fiber passthrough with active secondary mesh}
 

main.bib

@@ -3512,6 +3512,14 @@
   file = {/home/jaseg/Zotero/storage/AM4Q8Y76/Mohan et al. - 1999 - Simple accurate expressions for planar spiral indu.pdf}
 }
 
+@online{molexMolexSilverFlexible,
+  title = {Molex {{Silver Flexible Circuit Solutions}}},
+  author = {{Molex}},
+  url = {https://my.avnet.com/wcm/connect/d5fa4b27-de81-4aac-9bcb-cff3844b9eb3/Silver-Flexible-Circuit-Solutions-Brochure-EN-Brochure.pdf?MOD=AJPERES&CVID=oMyo8ki},
+  urldate = {2025-05-07},
+  file = {/home/jaseg/Zotero/storage/SY87W3RX/Silver-Flexible-Circuit-Solutions-Brochure-EN-Brochure.pdf}
+}
+
 @inproceedings{monfaredLeakyOhmSecretBits2023,
   title = {{{LeakyOhm}}: {{Secret Bits Extraction}} Using {{Impedance Analysis}}},
   shorttitle = {{{LeakyOhm}}},
@@ -5653,6 +5661,26 @@
   file = {/home/jaseg/Zotero/storage/S93U8AF3/Wang et al. - 2020 - Topological optimization of hybrid quantum key dis.pdf}
 }
 
+@article{wangTwinfieldQuantumKey2022,
+  title = {Twin-Field Quantum Key Distribution over 830-Km Fibre},
+  author = {Wang, Shuang and Yin, Zhen-Qiang and He, De-Yong and Chen, Wei and Wang, Rui-Qiang and Ye, Peng and Zhou, Yao and Fan-Yuan, Guan-Jie and Wang, Fang-Xiang and Chen, Wei and Zhu, Yong-Gang and Morozov, Pavel V. and Divochiy, Alexander V. and Zhou, Zheng and Guo, Guang-Can and Han, Zheng-Fu},
+  date = {2022-02},
+  journaltitle = {Nature Photonics},
+  shortjournal = {Nat. Photon.},
+  volume = {16},
+  number = {2},
+  pages = {154--161},
+  publisher = {Nature Publishing Group},
+  issn = {1749-4893},
+  doi = {10.1038/s41566-021-00928-2},
+  url = {https://www.nature.com/articles/s41566-021-00928-2},
+  urldate = {2025-05-08},
+  abstract = {Quantum key distribution (QKD) provides a promising solution for sharing information-theoretic secure keys between remote peers with physics-based protocols. According to the law of quantum physics, the photons carrying signals cannot be amplified or relayed via classical optical techniques to maintain quantum security. As a result, the transmission loss of the channel limits its achievable distance, and this has been a huge barrier towards building large-scale quantum-secure networks. Here we present an experimental QKD system that could tolerate a channel loss beyond 140\,dB and obtain a secure distance of 833.8\,km, setting a new record for fibre-based QKD. Furthermore, the optimized four-phase twin-field protocol and high-quality set-up make its secure key rate more than two orders of magnitude greater than previous records over similar distances. Our results mark a breakthrough towards building reliable and efficient terrestrial quantum-secure networks over a scale of 1,000\,km.},
+  langid = {english},
+  keywords = {Quantum information,Single photons and quantum effects},
+  file = {/home/jaseg/Zotero/storage/FCHS9D49/Wang et al. - 2022 - Twin-field quantum key distribution over 830-km fi.pdf}
+}
+
 @article{wegmanNewHashFunctions1981,
   title = {New Hash Functions and Their Use in Authentication and Set Equality},
   author = {Wegman, Mark N. and Carter, J.Lawrence},