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Entangled Photons Maintained Under New York Streets

physics.aps.org

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Re: Entangled Photons Maintained Under New York Streets

#11

Post by dhosek »

ars wrote: post #6
golergka wrote: post #5

Earlier quoted context omitted.

> In addition, it is also forbidden to transfer an object for a distance of 4 cubits This gave me pause.

In a public area you can not transport objects, the intention being that the Sabbath is a day of rest, and you should stay home or at least near your home and not do work. Note: Jewish law very carefully defines "public area", and it would take several pages of text to fully explain it, so before objecting be aware you may be lacking background knowledge.

I’m guessing it’s the cubits that gave pause more than the restriction. I first became aware of eruvim thanks to an article in the L.A. Times which talked about a new eruv being constructed in Venice. The article talked about the restriction on carrying and how the eruv allowed congregants to bring their keys¹ with them while attending synagogue.

⸻

1. Doubtless someone reading this is thinking, well, they could just get an electronic lock and use that to protect their homes but most Orthodox rabbis would prohibit this as there is the possibility of a spark being created by the electronic system² which would violate the prohibition on making a fire on the Sabbath.

2. This question comes up in Surely You’re Joking Mr Feynman, where Richard Feynman, asked about this by rabbinical students, told them that electricity was not fire and that a condenser across the switch would eliminate any potential spark, but they were unsatisfied with his answer.

Re: Entangled Photons Maintained Under New York Streets

#12

Post by asplake »

ars wrote: post #7
idempotent_ wrote: post #2

Interesting, a sort of quantum eruv https://en.wikipedia.org/wiki/Eruv Does anyone have any additional context on the throughput numbers? It says 20k photons per second at 99% fidelity and 500k at 90%, but what is the actual bandwidth needed for reasonable usage / computation?

20k (10^4) photons/sec is a TINY amount. An ordinary flashlight emits something like 10^18 photons per second. Even a star in the night sky sends around 10^8 to your eye. That few photons is not going to have much bandwidth.

They’re measuring individual photons, right? I’m old enough to remember modems slower than that. No doubt they will get faster, but what if they were used only for (say) key exchange?

Re: Entangled Photons Maintained Under New York Streets

#13

Post by tapotatonumber9 »

golergka wrote: post #5
idempotent_ wrote: post #2

Interesting, a sort of quantum eruv https://en.wikipedia.org/wiki/Eruv Does anyone have any additional context on the throughput numbers? It says 20k photons per second at 99% fidelity and 500k at 90%, but what is the actual bandwidth needed for reasonable usage / computation?

> In addition, it is also forbidden to transfer an object for a distance of 4 cubits This gave me pause.

Not 4 qubits?

Re: Entangled Photons Maintained Under New York Streets

#15

Post by [deleted] »

dhosek wrote: post #11
ars wrote: post #6

Earlier quoted context omitted.

In a public area you can not transport objects, the intention being that the Sabbath is a day of rest, and you should stay home or at least near your home and not do work. Note: Jewish law very carefully defines "public area", and it would take several pages of text to fully explain it, so before objecting be aware you may be lacking background knowledge.

I’m guessing it’s the cubits that gave pause more than the restriction. I first became aware of eruvim thanks to an article in the L.A. Times which talked about a new eruv being constructed in Venice. The article talked about the restriction on carrying and how the eruv allowed congregants to bring their keys¹ with them while attending synagogue. ⸻ 1. Doubtless someone reading this is thinking, well, they could just…

[deleted]

Re: Entangled Photons Maintained Under New York Streets

#18

Post by gradschoolfail »

dhosek wrote: post #11
ars wrote: post #6

Earlier quoted context omitted.

In a public area you can not transport objects, the intention being that the Sabbath is a day of rest, and you should stay home or at least near your home and not do work. Note: Jewish law very carefully defines "public area", and it would take several pages of text to fully explain it, so before objecting be aware you may be lacking background knowledge.

I’m guessing it’s the cubits that gave pause more than the restriction. I first became aware of eruvim thanks to an article in the L.A. Times which talked about a new eruv being constructed in Venice. The article talked about the restriction on carrying and how the eruv allowed congregants to bring their keys¹ with them while attending synagogue. ⸻ 1. Doubtless someone reading this is thinking, well, they could just…

Twice paused here

> bring their keys¹

Are these keys quantum??

Quantum-key bringing-about² is the main utility (afaik) of these underground quantum networks (pls don’t take this as an endorsement of the tech lol)

These networks have to work during Shabbat..

2 https://en.wikipedia.org/wiki/Quantum_key_distribution

Re: Entangled Photons Maintained Under New York Streets

#20

Post by ishtanbul »

bqmjjx0kac wrote: post #4
ishtanbul wrote: post #3

This is great but why can’t i get fiber internet in my bk apartment. Still struggling with spectrum coaxial pulling less than 5mbps today. No options on my block. Sheesh

Find a new apartment? Here's the FCC broadband map: https://broadbandmap.fcc.gov/home

that map is a great resource, thank you
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