Quantum Bridge's Friendly Neighborhood Quantum Networks
With great repeaters comes great responsibility.
I apologize for writing an article with an estimated 42-minute read time, but I am obligated to begin by regurgitating Spider-Man’s entire backstory.
Nah, just kidding.
You’ve seen the movies. You may have seen the cartoons. You may have even read some of the comic books. I’m sure you’ve got it.
What you may not have, however, is the story of Quantum Bridge’s repeater technology. It is uncanny how well it aligns with Spider-Man’s web shooter technology. If you’ll indulge me, I’m going to walk you through it.
Graph States
A single stream of Spider-Man’s web fluid consists of multiple, interwoven micro-strands. If you’d like to pause for a moment and read up on Kevlar and carbon nanotubes, you won’t hurt my feelings. The executive summary, though, is that this structure gives the stream its strength.
Instead of shooting out multiple strands of fluid simultaneously, Quantum Bridge uses quantum dots to fire off multiple photons simultaneously. The photons are then “interwoven,” in a sense, by entangling them into a graph state.2 As we’re about to read, the graph state strengthens this approach.
Photon Loss
Like a frayed rope, multiple micro-strands can break without snapping apart the entire stream. Depending on the needs of the storyline, one strand might be enough to allow Spider-Man to save the day. Then again, that’s why the micro-strands are so numerous; the stream is intended to not fail.
This is the strength of the graph state. Just like Spiderman losing micro-strands, Quantum Bridge can lose photons during transmission and it’s okay.3 There are lots of them. This solves a problem with memory-based repeaters, because these photons can’t be copied. The graph state is intended to not fail.
Multi-Party Entanglement
Spider-Man isn’t limited to shooting a narrow stream, so I’ve got two analogies for you here. First, he can cast a web with which can catch multiple baddies simultaneously. Second, he can use both wrists and cast streams in different directions. The latter has allowed him to stop trains, hold boats together, and other ticket-selling heroics.
A graph state isn’t limited to one target either. Quantum Bridge can use its all-photonic repeaters to send entangled photons to multiple destinations, catching multiple parties in its quantum network. I guess we’re going to have to call the Quantum Internet the World Wide Quantum Web (WWQW)?
Scalability
At one end of the spectrum, Spider-Man might shoot a little bit of web into a baddie’s eyes to temporarily blind him. At the other end of the spectrum, Spider-Man has, on occasion, constructed a massive Thor-like web hammer to smack around multiple baddies simultaneously. His web shooters are remarkably efficient.
Memory-less quantum repeaters are relatively efficient, as well. There are no interactions between photons and atoms, and there is no need to implement error correction with atoms. This makes the Quantum Bridge approach an easier approach to build out large-scale quantum networks.
News Coverage
This is admittedly not about the technology anymore, but we all know that Spider-Man gets outstanding news coverage. It helps that he takes exclusive photos of himself in action and then submits them as photojournalist Peter Parker — SPOILER ALERT — to the Daily Bugle newspaper.
The 2015 paper about Quantum Bridge’s technology is open access in Nature Communications and was highlighted by IEEE Spectrum. A 2019 proof of concept was published in Nature Communications and was also highlighted by IEEE Spectrum and the US government Quantum Workshop report.
Conclusion
Stan Lee, creator of Spider-Man and many other Marvel characters, famously made them flawed. He believed that having challenges would make them more relatable. Among other issues, Peter Parker felt guilt over the death of his uncle, he faced financial struggles, and he felt isolated by the need to protect his secret identity.
Building memory-based quantum repeaters has its challenges as well. Photons and atoms need to interact, error correction needs to be applied, and quantum information cannot be copied. Quantum Bridge’s all-photonic approach has its challenges, but it eliminates all of those as if helped by Tony Stark and Happy Hogan.
Removing memories makes quantum networking simpler and more scalable. While that might not be the only path forward, Quantum Bridge believes it’s the easiest. For information about Quantum Bridge and the market for this tech, check out the IQT Research report, “Entangled Networks: Enabling Technologies & Future Markets.”
https://www.deviantart.com/joinspider/art/Spider-Man-Red-Background-893964500
The concept is similar to the measurement-based quantum computing approaches of Xanadu, which uses cluster states, and PsiQuantum, which uses small graph states. Cluster states are more symmetric, whereas graph states are more general.
Fun fact: Graph states are not just useful for quantum communication (this article) and quantum computing (footnote #2), but also for quantum sensing.